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Show HN: Web page that parses and explains the label on a bike tire (fahrrad-tools.de)
631 points by moasda on Jan 30, 2022 | hide | past | favorite | 179 comments
History: Last year I had to replace the tire on my bike, and I was surprised how difficult it was to find a suitable new tire. There were a lot of numbers written on the casing, so I googled what they meant. In the end I was successful, but I didn't want to do the same work again for the next bike after I've forgotten the details. So I wrote this website.

Technically, the web page is kept very simple, no frameworks, no templates, no website builder. It uses HTML5, CSS and JavaScript, and it privides a responsive layout for mobile usage.

I'm happy to receive feedback. If you have tried the label of your bike tire, and it doesn't work, please post it as well. Thanks!




This is handy, but the good news is that if you're dealing with anything made in the last 30-40 years, it's all but guaranteed to have the ETRTO measurements marked on it somewhere.

Practically speaking there are two rim diameters you'll likely come across on all but old, "unusual" or high end bikes:

559mm: the ubiquitous "26 inch" mountain bike tire. Has largely fallen out of favor on high end mountain bikes, but there are zillions of bikes with 559mm wheels and frames sized for them out there. On high end mountain bikes, largely displaced by 29" or 27.5" setups.

622mm: "700c" road rims or "29 inch" mountain bike rims. Nearly universal on modern road bikes. If you have something else on a new road bike, you probably already know it.

Other sizes you might find in the wild:

630mm: The largely obsolete "27 inch" road rims. uncommon on new bikes, but you'll still find plenty of them on older bikes. Not even the slightest bit interchangeable with 622mm. Usually, you can't even switch to 622mm rims on frame built for 630mm because the brakes won't reach 4mm closer to the axle. Easily mistaken for 622mm if you aren't paying attention.

584mm is the "27.5 inch" mountain bike standard that splits the difference between 26" and 29". If you have this, you probably know already.

Once you've got the rim diameter right, the tire width is pretty straightforward: if it looks right, it is right. It'll be pretty obvious that a "29 inch" mountain bike tire doesn't go on a road rim, even if the diameter on both is 622mm. If you have needs under which that doesn't apply, you're probably already aware of them.

You can put hooked tires on straight sided rims safely (I have), but likely not the other way even if you could find dedicated straight sided tires.

Tubulars are a while 'nother animal, about which I know nothing :-)

ETRTO made it much, much simpler to get the rim size right when all of the various standards had different names to different people.


A couple of additions:

On non-disc road bikes, the tire size is limited by not only the width of the rims, but also by what the brake calipers can accommodate. For example, newer Shimano rim-brake calipers can accommodate tires up to 28mm in width, whereas older versions only up to 25mm in width. With disc bikes, the tire size is limited by what the wheel and frame can accommodate.

Gravel bike tires are all over the place, with companies making frames that can accommodate 700c, 29", and/or 27.5" wheels. And thus tire variations can be quite overwhelming.


Frame clearance can get you too. Cantilever brakes will allow you to fit a lot of tire, but you'll likely rub the frame long before you rub the brakes.


another "interesting" thing to consider is that some 700C gravel or cyclocross frames, designed for disc only, can take either 700C wheelsets or 650B. Because you no longer need to consider the vertical distance between the rim and the top of your fork, other than the general width between forks and rear stays for tire clearance.

650B is becoming increasingly popular for gravel.

There are a number of 650B tires that have intentionally higher than normal sidewall heights, so the total wheel+tire diameter is actually not that different from something like a 622x23 (aka 700C) skinny road bike tire on a traditional pavement only road bike.

https://off.road.cc/content/buying/13-of-the-best-650b-grave...

https://granfondo-cycling.com/650b-vs-700c/

If you have a disc only frame with wide tire clearance there exists the possibility of swapping between wheelsets that are either 650B or 700C depending on what type of riding you have planned in the near future.


My all road bike was built with 650b wheels since I didn't want skinny tires. The issue is that with this wheel size the bottom bracket is about 15…30 mm lower compared to 700c so you'll have to be careful with crank length due to the increased risk of pedal strike. Most of these bikes have a bottom bracket drop of 70 mm or more, while a frame designed for 650b specifically will have 54…60 mm. I don't know why the industry doesn't build frames with 65 mm BB drop since it would be in between, but I'm inclined to believe they prioritize 700c with 40…50 mm tires. But then one wouldn't be able to use anorher wheelset with skinny 25 mm tires for road, so you'll probably need a road bike. While designing for single wheel size only, the industry also ignores the needs of shorter people and most women.


My cross bike will take up to a 38mm 700c tire but I can size up to 45mm 650b with no changes! Small miracle of dropping rim brakes.


Schwalbe offers a good general overview:

https://www.schwalbe.com/en/groessenbezeichnung

The content is English, more interesting stuff under "Technology/FAQ". The German version looks different but features the same information:

https://www.schwalbe.com/technik-faq/ # german


No one really makes 26” mountain bikes anymore everything is 27.5 or 29 not just “high-end” bikes. Unless you’re talking about 26” bikes that kind of look like mountain bikes but aren’t really mountain bikes at all.


26" is still a thing in the market towards the lower end of the price range for something like a hardtail XC bike under $1200, that has some real capability.

But I do get what you're saying about things that are more like bicycle-shaped-objects sold at Walmart.


As an owner of a Walmart bike, this stings. I have a blast every time I ride that thing. I don’t ride enough to warrant a more expensive bike and this one has t limited me yet. Is all of high end biking this snobby?


I'll answer from the perspective of wrenching on bikes, which I did on a volunteer basis for a couple of years around 2006.

Walmart bikes are typically made with fairly low quality components. They're a total pain to put in correct adjustment, and they rarely stay correctly adjusted for long. It's also incredibly rare that they're put together right and adjusted properly from the store.

That said, I don't begrudge anybody for what they ride. If you're happy, I'm happy. If you find yourself riding more and visiting your LBS more in the future to get little annoyances taken care of, that's when it's time to spend more money on a slightly higher quality bike.

And if your LBS is a bunch of dicks about your Walmart bike, by all means go find a different shop. Good shops will educate you without talking down to you and let you make the right choice for your needs. If it puts a smile on your face when you throw a leg over it, it's a good bike for you!


I wouldn't say that everything has to be snobby - but there is a WORLD of difference between a $250 walmart "mountain bike" and something like a basic hardtail mountain bike you might be able to buy for $950-1200. I realize that maybe not everyone can afford that.

If a person has sufficient finances to allow for the purchase of a better bike, they will have a much more enjoyable overall experience of cycling on something like this, which although towards the lower end of the "real" bike spectrum, is still worlds better than a department store bike.

https://www.trekbikes.com/us/en_US/bikes/mountain-bikes/trai...

One of the reasons for the disdain towards walmart bikes among the cycling community is that many people have seen issues with them that are fundamental to safety - brakes that aren't set up right or don't work properly, wobbly wheels with loose spokes being sold as fit to be ridden, and so on. On the one hand you have questions about whether it's a good quality bike and will be enjoyable to ride, on the other hand there are often real and valid fundamental concerns about safety.


Short answer: yes. Long answer: absolutely, yes.

I owned a Walmart bike when I was 16-17. Rode it into the ground and had a blast. I did zero maintenance on it for two years (not ideal) and it serves the purpose. Bought a much nicer entry level Trek in my mid-20s and hardly rode it. It wasn’t until much later that I bought a bike that I rode more. It just happened that I could afford more and decided to spend more, but it absolutely wasn’t necessary. In fact, a guy I ride with in summer works at a LBS and still rides his trusty 1990s MTB (mid level). Oh, still regularly beats on most other riders too on it.

Nowadays Walmart is actually quite involved in the biking community and used to sell moderately high end bikes, though they may be out of the game now. Most people looked down on these bikes for some reason even though the entire group set was equivalent to a major brand high end bike. But it was sold by Walmart so how bad could it be? I suspect you don’t own one of these but the point is the same - as with many other hobbies, snobbery is very much thriving in cycling. Hell, I’m guilty of it to an extent too.


The Walmart thing is a bit interesting. A couple of the Walmart heirs are avid mountain bikers. They pretty much single handedly created Bentonville AR as a mountain biking destination.


I'll be the one guy: Don't feel badly about your ability to enjoy an inexpensive bike. I've ridden both high-end and low-end bikes. The high-end bike is definitely a better experience over long distances. On the other hand, I actually prefer my cheap beater (a Retrospec, a little above department store quality but not that much) when exercising on shared use paths, because it keeps me a bit slower around joggers and such.

While there is definitely a difference, it really doesn't matter if you get where you're going and enjoy the trip.


One and only issue is the rim width. There must be some limits how fat tire you can put on a narrow rim and vice versa?

But usually everything goes. On a backcountry tour 23-622 on front and 47-622 on back works best, because you dont want the bike to be front-heavy.


Yes, but like I said, if it isn't obviously wrong, it's probably close enough to work. I've put 35-559 and 54-559 on the same generic mountain bike rims. They both worked.

My road bike has 25-622 in the front and 28-622 in the back because a little more padding under my ass is pretty welcome at the end of a long day. I'll note that if you run radically different widths (and by extension heights), you'll likely find that you need to change the saddle angle to keep your weight on the parts of your body the can support it comfortably.


I can't imagine that the speed gain from a narrow non-driving wheel with less weight on it is worth the added danger on descents. Your front tire will wash out way before the rear starts to slide with that much different in traction.


You need fat on back because heavy load is there. Otherwise both would be skinny.

Situation is different nowadays when there are also easy rolling fat tires. In olden times 47-622 was always just very knoppy.

I soloed the Alaska Hiway with this arangement in 1987.

In olden times you also had to be very careful with the back axle. Until Shimano improved the design.


Apropos: Mericans would then say I have "700c" or "28 inch" in front and "29 inch" in back.


> 559mm "26 inch"

> 584mm "27.5 inch"

> 622mm "29 inch"

> 630mm "27 inch"

I've done no actual unit conversions myself, but just reading this, I'm highly confused. Quotes sorted by mm. Why is 27 not between 26 and 27.5?


The mm widths refer to exact rim diameter while the inch measurements refer to rim+tire diameter and are not exact.


This nails it. The nominal sizes are mostly (for some insane reason) based on the outside diameter of the wheel and tire. 27" road tires would have a 30mm tire size, whereas 27.5" mountain bike tires are probably running close to 60mm these days (haven't been keeping track of what's in vogue).

ETRTO is based on the bead seat diameter, which is what matters when you're buying a tire.


Not to forget: 29" wheels have the same rim diameter as 28" wheels used in road bikes (622mm). Obviously.

(The reason: mountain bikes use lager tires than road bikes, so the complete wheel is larger )


actual "27" is very old standard you might see such as if you discover an unused road bike from the early 1980s deep in somebody's garage. It's quite rare these days.

27.5 is used for mountain bikes so the rim profile and tire widths are a completely different thing than old "27"


As regards to tubulars and glue-on tyres: Only modification needed to tour on Spandex-worthy 622 mm racing rim was to screw a bigger hole for the valve, ie from Presta to Schrader.


In addition to your comments I would recommend that people upgrading or shopping for tires for a road/city bike familiarize themselves with bead types and tire weights.

Something like a "cheap" 700C 28mm tire with a wire bead can be quite a lot heavier than a folding bead (kevlar) more expensive road tire such as one that costs $55-70 per tire. Additionally there is a big difference in the quality of the compound used in the rubber for a cheap tire vs an expensive road tire. There are also specialty city oriented tougher tires like the gatorskip series that sacrifice some grip and cornering ability for purported resistance to punctures, also at the expense of being heavier.

If you ride regularly and have something like a flat bar road bike, and change the tires from 28mm cheap/wire bead to folding bead, you will IMMEDIATELY notice the difference in pedaling effort and cruising speed , subjectively measured by your own effort on a flat/level road, average effort, no wind.

You can feel this in the tire weight if you take the old wire bead tire off your bike and hold it one hand, and hold the unfolded new folding bead tire in your other hand.

As an example of a really good quality, folding bead, clincher type road bike tire: https://www.amazon.com/Continental-Grand-Prix-5000-Performan...

If you're using tubes there are also a number of benefits to be found from using the proper size/diameter range of tube, correct valve stem length of tube for your rim, and quality material tube. A good quality tube will cost a few dollars more than a cheap generic one. Using the example above of a 28mm road tire the appropriate size range of tube should be marked on its box from 25-32mm.

One other thought on rim type: If you are buying a $1700+ road bike new these days it most likely will come with a tube-using setup, but the rims will have the "new" square profile for bead lock that is also compatible for upgrade in the future to a tubeless tire setup with special rim strip and sealant. Older 700C clincher wheel sets generally are not compatible with the square profile bead lock required for tubeless. Newer 700C wheelsets should be compatible with conventional tube-using clincher beads as well as tubeless.

https://www.google.com/search?q=clincher+rim+tubeless+profil...

Terminology: To avoid confusion, tubeless and tubular are two different things. You're very unlikely to see tubular (glued directly to rim) tires in 2022 unless you're a professional, extremely serious about triathlons.


Correct tread pattern and pressure for conditions will make a significant difference in rolling resistance, far more than just about every other tire property (weight, suppleness, etc). Different conditions require different tread patterns and different tire pressures. As for weight, you’ll save maybe 100g of weight per tire, which is admittedly amplified due to rolling. Drop a single water bottle and you’ll be back on top. You won’t of course find many “performance” bikes with wire beaded tires.

Most paved paths are best paired with slicks/semi-slicks, even when wet (snow/ice is a separate discussion). Yet many hybrid/city bikes are equipped with a bit of tread depth. The tradeoff is durability and puncture resistance - slicks/semi-slicks can’t compete. And for people buying these types bikes, it is far more important that they reliably get from point A to point B without any flats or maintenance costs than saving a minute off their daily commute, so it is a fair trade off.

As for tubeless setups, I would hesitate to recommend those to anyone that needs this site (not that you’re suggesting that). If you don’t know what tire you need I would be willing to bet you have no idea how to fix a tubeless puncture, top up sealant, or remove/reinstall the tire.


Re: the weight of a water bottle, rotating weight is very different than static weight.

My experience with 28-32mm sizes tires on pavement in an urban environment has been that tires with tread on them actually have much less overall grip and cornering ability. This seems to correlate with data I've seen from third parties measuring the actual square mm area of a typical "contact patch" between tire and pavement. It seems counter intuitive, because on a car you want and need tires that aren't bald. But on a city/road bike, the best possible performance on pavement in the size range of 23-32mm with seems to be gained by having a treadless tire with a grippy compound.


That’s exactly my point :) Puncture resistance may be improved with more aggressive tread but handling and rolling resistance will definitely suffer. It’s all about the amount of contact patch on the ground. Same reason why on ice you want to run very shallow tread while on snow or mud you want a very aggressive tire. You can correlate this with slick car race tire vs a rally tire. One is great on road while the other wouldn’t get you far.

For a fun experiment, head out on a wet day and try to corner on both 28mm slicks and 33mm+ tires with a decent amount of tread (bonus points if you use a mud CX tread). Personal experience dictates that aggressive tread will treat you to a good dose of road rash while slicks will continue to grip far longer. I’ve far more experience with this than I should (one should be plenty).


As for the water bottle vs. rotating weight, I noted that as well. Which is why I compared dropping 100-200g of rotating weight (tires) to dropping a 500-750mL water bottle. It is a very rough comparison, I haven’t ever done the math to figure out how close they are, but I suspect it is close enough. Even 200g of rotating weight isn’t THAT significant when you consider the likelihood your pair of wheels weigh 2500g+ (assuming low end box wheels since we are discussing wire beads).


As with some other highly technical disciplines I think what we're seeing is the possibility of going down a rabbit-hole of optimizing for 1-2% extra efficiency in various subsystems/components...

For people who road cycle very seriously this will lead towards things like bikes that have a $6000-8000 all up cost with deep aero section wheels, expensive tires, ultra lightweight components to put the whole thing near a UCI-illegal weight, and so on.

It's probably easy to spend $1500 on a road bike combined aero bar-stem package that comes out of a single piece CF mold and has very marginally better aerodynamic performance in wind at >35km/h, but the returns are minuscule.

There is definitely a phenomenon of diminishing returns with increasing money spent above a certain point, that would be difficult to subjectively notice unless tested by a person that rides a very large amount like >10,000 km/year.


Let's also not forget the impact of visiting or not visiting a toilet before riding. The weight change dwarfs most of the differences between single component choices, possibly all the way up to most of the components combined.


Not to mention risks and extra time added for mid-ride bathroom stop! If you don’t coffee and poop before a ride, are you even a real cyclist?


Don’t underestimate middle aged men in lycra with too much money to burn. They’ll spend hours obsessing about individual components and won’t bat an eye when it comes to spending $15k or more (Canadian, a bit closer to $10k USD/EUR) on a brand new bike every couple years, $3-5k on the newest dimpled wheels from the big Z manufacturer, tires, and so forth, all in the name of besting their mates in the Saturday morning world classic coffee ride.

While I don’t strictly identify as above (I’ve more sense than to spend $1000/watt, or so I like to claim anyway), I do my fair share of purchasing the extra few watts. I’ve spent an embarrassing amount of time obsessing about what the optimal tire choice is for my next Cat 3 CX race. At least I’m realistic enough to know the hoards of 16-20 year olds with more handling skills and less fear will destroy my every day of the week. Joke is on them because they’ve real life coming to crush them :p

In all seriousness, I know fully well the 5-10W gain is marginal for me at best and will only get me so far. Genes, age and hours in saddle cannot be purchased. Being a late comer to the sport and not being blessed with the requisite body type, I can’t have any one of those three, but I can however throw more money at the hobby, unlike the younger ones can. And why not enjoy myself while doing so and ride around in style.

As for diminishing returns, don’t talk to bike enthusiasts about those. They’ll only be outdone by audiophiles


I'll just leave this here: https://www.youtube.com/watch?v=9epG_qaCimU.


> Don’t underestimate middle aged men in lycra with too much money to burn.

I think without middle aged men in lyrca spending $10k on bikes, most of the performance/road oriented bike shops in major metro areas would go bankrupt, because the profit margin on some of that stuff has to be insane. Particularly the accessories. Yes, I totally need a $95 carbon fiber bottle cage... Hook me up!


> I think without middle aged men in lyrca spending $10k on bikes, most of the performance/road oriented bike shops in major metro areas would go bankrupt, because the profit margin on some of that stuff has to be insane. Particularly the accessories. Yes, I totally need a $95 carbon fiber bottle cage... Hook me up!

The markup on higher-end parts and bikes is quite ridiculous. I've SRAM Red eTap on my road bike and cassette alone is over $500. Compare that to a Rival eTap cassette at $180 (two steps down) or Force eTap at $260 (one step down) and it is enough to make your head spin. Or if you want to stick to "old technology" and go with 11sp Force/Ultegra, you can get them for $130. I half-jokingly say that I'll sell the bike before any part wears out as it will be more cost effective to replace it.

My approach is to purchase lightly used high end bikes through private sales. Find a trusted source and let them take the initial hit. Covid put a bit of a dent in those plans due to lack of bikes everywhere, but at least there's still some deals to be had as you approach top range. You can forget any deals for bikes under $5000, you're likely to pay similar prices for used as for new.


Side note - loving the downvote! I can only guess a local Cat 5 legend got upset they didn't win their Tuesday night worlds even after spending $4k on Zipp 454s. That or didn't bother to read my whole post where I'm poking fun at myself for doing precisely this :p


As somebody that's now literally a middle aged man in lyrca sometimes - I find the whole phenomenon really amusing, but then again, I've also been riding since I was a lot younger, and poorer, and the best I could afford was an all-aluminum specialized allez with 9-speed 105 stuff on it.

Back in the day, I probably rode 4-5x more cumulative km per year than I do now. And at that time, I found middle aged men in lyrca with more money than common sense to be equally funny.


Have you taken a look at prices of a used Allez lately? Put a few IG/TikTok faces to it and it doubled the cost. Once upon a time it was a cost efficient way to race crits and not worry too much about cost of crashes. Now it is apparently a high end highly desired bike …

Edit: I’m also a ma… hang on, when does middle age start? I may still have a year to go technically! (But not in reality)


In 2005 I paid $1500 (USD) for an aluminum allez elite with the 9 speed 105 on it... Cheapest things on it were the FSA crankset and the fairly cheap 20 front/24 rear generic specialized house brand wheelset. Equivalent thing today would probably be a lot more. 10 speed tiagra is probably superior in every way to the groupset I had then, but a comparable bike now might be $2600? Or more.


Thanks a lot for the insights!


Thanks for putting this together! There are probably another half dozen vastly less common sizes that you might encounter in reality (e.g. kids' bikes, adult BMX, folding bikes, jogging strollers and bike trailers). I can see this being a huge help if you have one of those and you're trying to find a tire in a pinch.

I have a Brompton and a BOB trailer. I have no idea what size tires they take. The BOB must be a common size for a kid's bike because I blew a tire and had to replace it from Walmart while touring. Being able to type in the size and know wtf I need would be a huge help if you're calling around and the shop can't see the tire in question.


https://www.sheldonbrown.com/tire-sizing.html has (i think all?) of the edge cases you're going to encounter in any bike made after about 1925.


Sheldon Brown is the go to for everything like this.

There are no affiliate links, and he went way beyond the company he worked on, it's a pure act of love and is super comprehensive. It's just info to help you.


I would caution people reading that site to double-check anything they see there, or simply consult a much, much older version from archive.org.

Sheldon passed over a decade ago, and the site has been modified over time by a guy named John Allen. He fancies himself an expert of similar caliber, but has a tiny fraction of the hands-on experience Sheldon did.

He's made a number of edits/additions injecting his personal opinion. For example: about belt drives, of which he clearly has no personal experience.


Huh, I had a look at the belt drive thing - Allen added that in 2012(!) when belt drives were still relatively new - Gates went mainstream around 2009, and Center Track appeared 2010-2011. At the time many more belt drives would have been retrofitted onto old bikes instead of frames designed for them. He may not have had the experience then, but should have by now...that definitely needs an edit.

And wow, over a decade indeed, I can't believe its been so long :(

(FWIW my main bike has been belt drive & Rohloff geared, dynamo lights for 6 years now, the reduced maintenance is great, I can just step on my bike and go)


For anyone else stumbling across this, sheldonbrown.com has a wealth of high-quality information about bicycles, and it's rare that I don't look there first.


100%. If I’m doing my own maintenance (for just about anything) or want to build up some Franken-bike, I read up on my Sheldon “thank god that website is still around” Brown.


Semi-tangential, I took my fixie to Harris Cyclery for a tuneup before it closed. Boy, was I floored when the guy working at the counter told me that fixies weren't cool anymore. Sheldon was a big part of my journey to riding fixed gear. I learned everything I know about bikes from his site and he even answered questions personally by email.

I'm pretty sure when the guy said fixies weren't cool, I heard Sheldon spin in his grave a little.


Yeah the hipsters ride ill-fitting vintage steel racers now, some of the girls look so uncomfortable straining forward to reach the brake leaver. Fixed gear has gone back to being for a few enthusiasts and messengers and other bike weirdos like me. I’ve ridden one as a daily for years and years due to how awesome the virtually zero upkeep is, plus I personally find them safer, especially in winter.


Don’t worry, fixies are still cool among a select bunch of people. I’ve never cared for them, but plenty still do. There is also a budding fixie racing community outside of the track (including crit and CX), which is simply terrifying to me.


Thanks, this link definitely helps to cross-check if I got the mapping right.


Heh. Even in bicycle-rich countries like Germany and the Netherlands, these numbers are somehow still tricky. I guess it doesn't help that they are often hard to read and a lot of the numbers are actually redundant.

So yeah, useful! And my compliments for the neatness in your data privacy approach.

At one point I just took the old tyre into a bicycle repair shop and asked for the proper replacement, and the person who sold me one even managed to get the wrong one (they replaced it for the proper one afterwards of course). It used to be that most normal use bicycles all had the same tyre, and only racing bikes had those weird French style ones, but newer bicycles tend to have fatter tyres (which is not a bad development for sturdy day-to-day bicycles laden with groceries, an adult cyclist, and a child in front or behind the cyclist).


Thanks!


Huh. I thought the C in 700C indicated that the tire was a clincher as opposed to tubular but that seems to be wrong.

You tool says:

> Reifenhöhe C: ca. 39 mm (French designation)

but it says that for 700x19C as well as for 700x40C which seems odd?

The wikipedia page for Bicycle wheel [1] says:

> The ISO 5775-2 standard defines designations for bicycle rims. It distinguishes between 1. Straight-side (SS) rims 2. Crochet-type (C) rims (...)

and also

> Road wheels may be designed for tubular or clincher tires, commonly referred to as "700C" tires.

but it doesn't explain the B in 650B.

Sheldon Brown [2] says (emphasis added)

> A second number or letter code would indicate the *width* of the tire. (26 x 1.75, 27 x 1 1/4...650B, 700C...)

The wikipedia page does mention both 650B and 650C and that the ISO diameter differs by a few mm. So if I understand right, these codes (650B and 700C) specify the full-wheel diameter (650/700) and the letter indicates how much of that diameter the tire needs to make up, i.e. a 650B rim is slightly smaller (571mm) than a 650C (584mm) and the tire needs to make up that differencxe to get to 650?

[EDITED] 700C rims are ISO diameter 622mm, which matches with 2x 39mm tire width: 622 + 78 = 700mm. So I guess the intended tire height at time of standard-invention was 39mm?

But in practice a 700x19C rim-tire combo will be smaller in diameter than a 700x40C so I guess they're not fully "700C" standard compliant?

[1] https://en.wikipedia.org/wiki/Bicycle_wheel#650B_gravel_bicy...

[2] https://www.sheldonbrown.com/tire-sizing.html


Pasted description below from Sheldon's page. The A/B/C designation is even more confusing when you consider 700C wheels/tires which these days range from the uncommon 19mm to well over 40mm.

In the French sizing system, tires are designated by a three-digit number, which may be followed by a letter. The number is the nominal outside diameter of the tire the rim was originally designed for. The absence of a letter indicated a narrow tire; "A", "B" and "C" indicated increasingly wider tires."A" was originally a tire about 30 mm wide, so the 650A rim is pretty large, 590 mm. If you add the top and bottom 30 mm tire thickness to 590, you wind up with the 650 mm tire diameter.

The 650C size was originally intended for a quite wide tire, about 40 mm wide. Top and bottom 40 mm tire plus the 571 mm rim size again bring you to a 650 mm outside diameter, even though the rim was smaller.


Interesting historic context!

My understanding is that in the current world the suffix doesn't really matter, since all 28" rims and tires are marketed seem to be marketed as 700c, and all 27.5" ones as 650b. The height of the tire pretty much correlates with the tire width, so one would rather look at the tire and rim width to determine whether they are compatible (wider rims should be used for wider tires).

And it's actually fun that 700c bikes are usally ridden with narrower and lower tires than 650b bikes (which was in the recent years mostly used for mountain bikes and tire width of >= 2.3"), despite this designation claiming the opposite.


In the mountain bike world, there's really only two modern standards - 650b (also called 27.5in) and 29er's. 26er's were a thing for the longest time, but really no one makes new bikes in that size anymore.

We're mostly riding on wider tires, 2.3 seems to be a rational minimum for real trail riding, and you'll often see widths of 2.6 and beyond (and fat bikes of course go way wider) on both 27.5 and 29in bikes.


Pinkbike has a good article on rim width [1]

[1] https://www.pinkbike.com/news/rim-widths-comparison-test-mou...


Actually 650b is used when the tire width is less than 50 mm (randonneur and gravel bikes) and 27.5" when the width is over 50 mm (mountain bikes). Jan Heine and Kirk Pacenti reintroduced this size.


Wow, thank you very much for the valuable information. I will check how to improve the page accordingly.


If you think decoding those numbers is tough, wait until you try fitting road (700c) tubeless tires. Buying is the easy part as in theory any 700c tubeless tire will fit provided you're within the appropriate width range, which is relatively generous (provided you respect hooked/hookless). In practice it is far more complicated and the experience can be a nightmare. Sometimes the wheel/tire manufacturers don't follow standards, other times they do but results leave something to be desired. You have Uniform Standard Tubeless, Tubeless Ready, Tubeless Easy, Tubeless Compatible, hooked, hookless, yet no real guarantees the tire and wheel will be compatible.

I fit Continental GP5000TL (depending on the generation and width, they are notoriously difficult to mount) to two different sets of wheels. One set of wheels gave me a hard time and it took 30-45m per tire, but they eventually went on. On the second set of wheels, one went on easy enough. The second took well over an hour and resulted in multiple blisters (and much cursing) even after using every known trick. Schwalbe Ones in comparison mounted in a minute with no struggle, and actually hold air better than the Contis which can supposedly be used without a sealant.


It is really pissing me off that "tubeless ready" wheels and "tubeless ready" tires have made it infinitely harder to just fit a tire with a good old tube inside.


Can you elaborate on this?

With the exception of hookless rims (which are not common yet, at least here), TL wheels will take a clincher tire and tube, and TL tires will take a tube. The potential incompatibility comes from TL tires and TL wheels, not at all related to tubes, and is because of lack of spec and manufacturing tolerances.


Sure, except now rim and tire manufacturers go to the opposite ends of manufacturing tolerances on their respective parts because no one wants some niche road tubeless setup popping off at 7 bar. The result is tires like the GP5k (not even TL version) where I've struggled to get even the first side over, on rims that are tubeless ready and, no coincidence, have a history of being difficult to fit tires on.

I want to be able to fix a flat outside, not call an Uber.


Ah fully understand, I thought you meant there is somehow incompatibility between tubes and TL wheels/tires.

I’ll echo your frustration 100%. I found Schwalbe Ones are much looser fitting and have no problem mounting them on two sets of rims I have that will barely take a GP5K.


normally when fitting a tire, you put the bead on one side in the "gutter" in the center of the rim where the diameter is narrower while you lever on the bead on the second side. leaving the first bead loose and un-seated while you pop on the second bead makes it pretty easy.

rims with thick rim tape designed to seal with tubeless tires have much less gutter, so it's a bit more difficult to squeeze the last bit of the tire onto the rim. they're compatible, just difficult to work with.


There are tire/wheel TL combos that are just not compatible, no matter what you try. Centering the tire is key, soapy water helps, you may need to warm up the tire, a tire jack may be needed in some cases .. but none of those will work 100% of the time, which is ridiculous.


Did you try a tire bead jack? The Kool Stop one has worked wonders for me getting GPs on.


Did I break down and take it to the LBS for mounting? Also, absolutely not. Why pay someone $20 to mount the tire when I can spend an hour fighting it and end with nasty blisters?


I figured someone would ask - no, I didn't have one handy, all LBSs were sold out and online orders would have taken too long.

Did I learn from the experience? Absolutely not, still haven't bought the Kool Stop jack ...


I've heard quite a few people complain about GP5000TLs, but that's what I've been using for a while (on Prime carbon wheels) and haven't had too much trouble with them. With tubeless tyres, you really have to make use of the inner rim well (i.e. the middle bit) to give you the crucial extra mm or so. At least with tubeless tyres you can use tyre levers to get the last bit on and not worry about puncturing a tube. Schwalbe Ones are easier to fit in my experience, but they seem to have the durability of butterfly wings and even worse, they can get slippery in the wet when they're at high pressure (e.g. over 70psi).

I've seen videos of people easily fitting tyres using just their thumbs, but I refuse to believe that's possible.


It entirely depends on the rim. First generation GP5000TLs were impossible to fit on some rims, difficult to fit on most rims and reasonable on a few. Second generation (I think late 2020/early 2021) are a slightly looser and will fit on more rims. I can't speak about the latest gen. released late last year.

I personally love GP line of tires (used 4k/5k clincher and 5k TLs) as they have a good compromise of puncture protection, tread wear and rolling resistance. They generally rate at the top for just about any tire I'd use in a non-race scenario. I will not buy another pair though until I switch wheels as I have no desire to torture myself. I did not go as far as to bake the tires to loosen them, but I did let them sit out in the sun which made a bit of a difference.

The other factor to consider is roadside repairs. If you have a really hard time mounting the tire initially and you puncture severely enough to need a tube (sealant leaked and plug won't hold), you're likely calling for a ride back. I did find they loosen after 500-750km so you are more likely to be able to fix it roadside if needed. I sliced the sidewall on my almost new GP5k but thankfully the plug held. Irresponsibly I used it for another 500km+ until it would no longer hold pressure overnight, but I do not recommend that route!

As for using tire levers - buyer beware when it comes to carbon. I resorted to levers, but you do run a risk of permanently damaging your wheel. I have seen a picture of someone put one of the plastic with steel spine levers straight through their rim doing this. A tire bead jack is a far safer and far easier option (though I've yet to buy it).


Indeed, there's one bike in the family fleet, a Surly with tubeless-ready 650b's, that are a beast to mount. I can get them on and off, but I have strong hands -- jazz double bassist for 40 years. My spouse has no hope. If she flats on a ride, she has to make the Call of Shame. ;-) This isn't reasonable.

As I read somewhere else, Frank Schwinn and Frank Brilando wanted a bike to be serviceable by a 10 year old.


I did okay with gp5000 clincher for tubes, and just two cheap plastic tire levers and my own thumbs. But what you have described for the tubeless version is something I've seen very widely reported from a number of other sources as well.


Thanks for this, I remember going down a rabbit hole parsing the codes on my last set of tyres trying to figure out what to replace it with (I learned there's a standard, ETRTO [1]) and I'm glad something like this now exists! Great work. Do you have plans for it beyond what's there already?

[1] https://en.wikipedia.org/wiki/European_Tyre_and_Rim_Technica...


Thank you! Right now, I just implemented my knowledge from my personal notes when I had to replace my tire. Maybe I'll add some more tools after I learnt something new about bikes.


Thanks for sharing, this looks really useful. I have started biking again recently and the labels on the tire are super confusing. Do you have any plans to extend this(attempt OCR or something)?

I tried looking at the source a bit and it seems like your markup is pretty clean, if a bit unreadable after minification. I liked the classes "question" and "answer". It looks like you are planning on using affiliate links to monetize it?


Thank you for the feedback. OCR is a great idea, for me it seems to be quite difficult to implement and probably requires a mobile app.

The affiliate links are just a side effect to pay for the hosting.


You could use a simple client-side JS OCR library, like GOCR.js[0]. It may only work on good photos of relatively new tires with clearly printed text, and that's not always what bicycle tires look like when you're looking to replace it, so not sure how useful it'd be.

[0]: https://antimatter15.com/gocr.js/demo.html


I tried to to use GOCR packaged with Ubuntu on playlists, expecting it to work well since it's computer output. But it turned out not working so well. I also tried scaling the text but that didn't fix it.


Interesting approach, thank you. Sure, old tires might be hard to scan, but definitely worth to think about.


Can I ask why OCR, other than to learn something new. From a functionality standpoint you’ve hit the nail on the head. Some suggestions in this thread however start to take away from the appeal of the site. I suspect the target audience will much rather type out the dozen numbers/chars than they will attempt to mess around with taking a picture and having OCR take over. I’d be willing to bet the time to enter data is comparable and if there are any savings to be had from OCR (doubtful) it would be measured in seconds at best.

Identify the audience and build the product for it. A tech savvy audience (HN) would love to see OCR because we have nothing better to do than look for “latest cool gadgets”.


Good point, the page is designed for easy usage and beginners, rather than experts.


You could possibly do it server side. I would personally implement it as a Flask server that took an image, ran it through either Pytesseract (quick, got to manually preprocess, needs tesseract installed) or Easyocr (slower but works out the box) then send back the if and only if it was a valid tire-info-string to avoid people abusing it for other purposes.


Wow, thank you, I will check that.


There is a barcode scanner on https://schnelltesttest.de/

Their source code is here: https://github.com/zerforschung/schnelltesttest.de


Thanks for the tip, I will look into it.


I tried to buy bike inner tubes on Amazon and I just could not do it. I would do a search, go to a product page, and the thing I wanted simply was not on that product page. I wound up going to a local bike shop and was in and out in less time than I had spent trying to find them online.


Yeah, tubes are complicated by the fact that one tube size fits more than one tire size, plus there are two different kinds of valve stems, and some contemporary wheels need extra long stems.

One favor you can do yourself is to start patching your tubes if you're not already doing so.


While I commend anyone who takes the time to patch a tube, if you have kids/job/life/etc it is so much quicker and easier to just replace the tube. They can be bought for very little and fitted before you've even tracked down the hole on the old tube. If you are out on a longish ride, you probably want to be carrying full size spare tubes tucked in a pocket or bag anyway - patching at the roadside is not fun, and again takes far longer than just popping in new tube and getting on your way. Tubes with no air in them are very small/compact.

Over the past 20 years of riding a collection of ~10 bikes, I would be lucky if patching tubes would have saved me even 200 dollars. What your time is worth to you may be different, but for most working adults I don't think patching makes time-money-sense. Assuming you already have a pump, instead of ordering a patch kit to carry with you on rides or keep at home, just order one of whatever tube your bike needs (usually ~5-9 bucks), some tire levers (reusable, 5 bucks) and keep in drawer until day dawns you need it. The rare time I buy a new bike with a weird innertube I don't already have, I buy a couple of spares immediately with the bike.


That's fair, and you need a spare tube anyway because not all flats are repairable. I carry a spare tube and a patch kit, but typically patch the punctured tube at home. The patch kit is in case I get a second flat -- a vanishingly rare occurrence thanks to puncture resistant tires.

Each person has to satisfy their own sense of time and money, which I suspect is partially subjective for most of us. For instance I actually have spare time, and am not paid for working extra hours on my day job. Admittedly, being self sufficient for bike maintenance is part of "life" for me, and even when my kids needed more attentive care, I was always able to carve out 15 minutes to patch a tube.


> I carry a spare tube and a patch kit, but typically patch the punctured tube at home.

Paranoid me always carry two spare tubes, a patch kit and a puncture repair spray (it's supposed to inject a product that reinflates the tyre immediately, allowing me to keep riding and then go home without having to repair or remplace the tube, but since I've never had the opportunity to use it I can't tell if it's really effective).


Puncture resistant tires have really allowed me to be a bit more relaxed about flats. Also, fortunately I don't live in goat head country. Here in Wisconsin, a vital supply for fixing flats while on a ride is mosquito repellent.


> Here in Wisconsin, a vital supply for fixing flats while on a ride is mosquito repellent.

Where I am, in the south of France, as well. And they are of the really aggressive species!


You are right, for the first time it's confusing to find the right tube as they fit to several tire sizes.


Switched to tubeless last year, but prior to that I've patched a few as an emergency and tossed it when I get home. All of my patches held but I didn't trust a single one. $10/tube was cheap insurance against a potential disaster.

I do run latex on my gravel/cx bike and those go into the trash immediately as they're far more difficult to properly patch. Hurts a little more when you pay 2-3x the price though :(


is there a trick? when I first started riding I got a bunch of patch kits. I'm doing this in the shop so I have plenty of time to clean the area, rough it up. clamps to make sure the patch is firmly set, etc. after about..10 tries? I just gave up. I am religiously for wringing the last bit of functionality out of something before burying it...but it just wasn't worth it.


Are you using self-adhesive patches or something that uses a tube of glue? I never got on with anything other than Rema's patches.


Indeed, the answer is Rema. There may be some other brands that are as good, but Rema forms an actual chemical bond between the patch and the rubber of the tire. The vulcanizing fluid prepares the surface of the tube so it will bond to the patch. Better living through chemistry.

Everything else, check. Roughing up the patch area, waiting a few minutes for the vulcanizing fluid to dry, squeezing the patch for a few seconds after applying.

I've never had a problem with the little sandpaper that comes with the kit.


The sandpaper used in most kits is near useless. The sheetmetal "rasp" rougheners work much better to get the mold release broken up.


Amazon's search is completely useless if you're looking for specific things. It simply ignores what you typed and throws random sponsored products at you.


This is the sort of websites we need more of. It's simple, fast and useful, and not monetized at the users' expense.


Thank you :-)


The most useful link on HN of the year has already been posted. Those labels are baffling.


Thanks!


Nice site!

I'll also suggest an easy thing to add: You could add an explanation of folding tires vs wirebead tires. Often even tires with the same dimensions come with both formats. The difference and the benefits of each version (price vs weight and rolling resistance) are understandable for most people.


For anyone interested in tyre rolling resistance I can recommend:

https://www.bicyclerollingresistance.com/

It’s a wealth of standardised tests of tyres and tubes, if like that sort of thing.


Forgive me, but apparently this is the 'post-truth' age: What makes the person and their tests credible?


That’s a good question!

He’s published his test protocol[1] so I guess the tests could be repeated for verification.

I don’t think that’s happened yet though or much other peer review either.

The guy running the site launched it as a personal project in the absence of all independent test data except for manufacturer’s claims (and they all claim to be the best).

It’s also worth noting that the fastest tyres in test might not necessarily be fastest in use.

Eg stiffer mtb tyre might roll slower but give more support when going hard downhill.

He’s pretty up front about his test being quite specific and designed for repeatability.

1. https://www.bicyclerollingresistance.com/the-test


That helps me understand. Thank you!


Thank you, good idea, I will add an explanation.


Nice, well done. I'll bookmark that one!

Let us know how much you make with those Amazon ref links while being HN's #1


Thank you! So far, I haven't even earned a coffee, but it would be great if I could compensate the hosting costs in the long run. :-)


Great idea! I made a mess out of buying a new stem for a road bike and I can confirm that reading/guessing numbers from bikes parts is non trivial.

How are you going about monetizing this? Affiliate links?


I've never understood why bike manufacturers don't make it easier to look up parts by serial number. SRAM has done this right, you can search for parts based on s/n and it will give you exact specs (s/n is stamped onto the part). Their service manuals are also very well designed and free!


Thank you! Yes, there are affiliate links on the page to get some money for the hosting, but that's not the main goal of the page.


Very nice. As a long time cyclist with a fondness for bikes thrown together from odd parts, finding suitable tires that are affordable is always an issue. I've learned that the ETRTO number is the only thing I need to know. Virtually all modern tires provide that number.

There have only been some rare cases such as a 1963 Schwinn repack cruiser, where I needed to do a bit of research to match its oddball tire size. Then the Sheldon Brown website came to my aid.


Thanks!


Needs a note re tubeless setup, esp for mountain bikes. Fewer punctures, easier to repair in the field. Tubeless-ready tires should also have a note on the sidewall.


Thank you for the hint!


Valve length is important if you have deep section wheels, something missing from your tube FAQ. Most 40mm valves will not fit moderately aero wheels.


Thank you very much for the helpful hint. I will extend the FAQ accordingly.


The first scenario in the FAQ sounds more like a pinch-flat to me. This happens when you ride up a curb or over a rock and the tire compresses, pinching the tube between the rim and the curb. Running higher tire pressures, using a product like CushCore, or as the author discovered running stiffer casings can all help reduce the incidence of pinch-flats.


A pinch flat (aka snake bite) will generally have two pinholes, making it relatively easy to identify.

With that said I have never had a flat on the outside of the casing without actually an obvious sidewall tear/puncture. Definitely possible, but I would say it is far less likely.


I'd also add an important point - never replace a punctured tube without thoroughly checking the inside of your tire for sharp objects. You'll likely only make this mistake once.


I've never really found a good way to check - visual check can miss things, running your hand around the inside works but you're liable to get something such in your hand! Wiping a around can work. But I've not come up with anything better? Maybe a tissue, or microfibre cloth will snag more easily and avoid missing something?


I take the chance and run my hand on the inside. Gloves should usually work well too, though I use fingerless on road.

For off-road riding (cross) I pinch flat almost exclusively so I don’t bother checking around. It is pretty obvious when you smack a root or rock.


I am often still wearing my biking gloves anyways, so I run my hand around inside, and then toss them in the wash when I get home.


Thank you for the hint.


What I would love is something that can give alternative tube sizes.

My bike uses 22x3 tubes, which are unusual and hard to come by. However, there have been reports of 20x4 bike tubes or 18x3 motorcycle tubes also fitting.

A website that recommends more widely available or cheaper “this will also fit” tubes would be amazing.


What are those numbers in reference to? And what size tire do you have? Tubes can stretch to around 3x the size of a tire. A lot of enduro riders carry a 26" tube for their 29er to save some hip pack space.


You are right, my tube page also doesn't list a fitting tube for that size right now.


Great work and thanks for NOT making this an app. The people that creat the standard should have done this.


Thanks!


I wish ETRTO was more common terminology for consumers. It tells you most of what you need to know with very little ambiguity.

It would also be great if tyre widths were in MM across the entire size range. Even in Europe, mountain bike tyres are sized in inches!


This is really great!! Definitely something that would have helped me back in the day before I realized how complicated / annoying getting proper tires was.

I won't need it for my own bike anymore, but definitely when I get a new (used) one next.


Thank you :-)


Thank you for that. Really.

Is there a way to decide which tube to use, having the measurements of the frame? (the round metal part on which the tyre goes on sorry if this is not the correct expression, I am no a native speaker of English)).


Thank you! If you know the diameter of the rim (the round metal part in your description), e.g. 600 mm, and you can assume a tire width, e.g. 40 mm, then you can search for "40-600" and find some tubes:

https://fahrrad-tools.de/tube.html?text=40-600


Thanks. This is especially the "assume a tire width" that is a problem - are there hard rules for which width is possible for X (X being something I measure)


I wonder why you focus on the tube first? Wouldn't it be easier to choose a tire for your rim first? Then you can also easily find the right tube.


Ah la la - sorry. I meant which tire of course.

My problem is that I have a rim that is there for good, and then I would like to see which tires are possible for that given rim (there are several choices of width and I do not understand what drives the minimal and maximal width - I can imagine the the brakes are a limiting factor for the maximum width, but maybe this maximum is smaller because [some measurement of something]).

Then comes the tube, thus the OP's useful page.


you're a very kind person to create such a tool. is there a way to make it work offline so one could use it without an internet connection? just a thought -- it seems like it'd be a useful standalone program.


Thank you for your feedback! Permanent offline use could be achieved through a mobile app, I will think about it.


Why would one need that? If one makes a long bike tour into areas without internet one is hopefully prepared well enough to remember the one size for one's bike.


I guess it's mostly about convenience and reliability.


Great work. I've replaced several tires and every time it's the same ambiguous lookups followed by crossed fingers as I install the thing. I'm sure I'll use this page in the future


Thanks!


I like putting 700x32 tires on my bike. Haven't issue attention to the other numbers. Are they mostly redundant? Guessing for a casual rider they don't have much of an impact?


A somewhat important factor is if the tire is slick/smooth, knobby or in-between. For casual riding you probably want something in the middle so that it's fine on most surfaces.


Slick/smooth unless you're doing mud/snow. The tread compound matters a lot more than the tread pattern, until you're into sloppy stuff, and then the tread starts to matter.


You're probably OK as 700x32 is a fairly common designation. The ETRTO for that tire is 32-622.


The ETRTO numbers are the most useful ones. If you just look on them, you're good to go.


Yeah, that 28" number is goofy. In Mountain bike terms, it's a 29er. For road usage, it's 700c. But the rest of the world, at least those who measure in mm, use 622.


Yes, the outer diameter is a bit more complicated. From this point of view, some bikes can use different tire sizes.


That's what I learned around 1984 from reading a book. 10 years before internet was a thing :) Have ignored all other numbers since then. Have not had any worse problem than some clerk might have given me a strange look when I bought tires referring to ETRTO numbers.


https://en.wikipedia.org/wiki/ISO_5775


There don't appear to be any newlines. Wasn't it hard to edit by hand that way? (Unless I am missing something)


Are you looking into the HTML code? It's minified by the deployment script.

That's not the way I edit HTML files. :-)


May I ask what you’re doing in your deployment script?


The deployment script minimizes the text files, creates gz files for nginx, and copies the files to the webserver host.


This is really cool, thank you for sharing!

It would be neat if the information and links could be localized.


Thank you! The web page is in English and German for now.


Nit: Send me to the US version of Amazon if I'm from the US.


Good idea, I will think about that.


The responses here validate the existence of the web page.


Make this use the camera so You can just use a photo of the tire :)

Rad!


Thank you for the hint!


I've also found http://biketiresize.com/ to be useful.


Nice website. Where did you source your data from?


Thank you! I used the official product specification from the manufacturers.


TIL that has nothing to do with pressure. Huh.


[deleted]


Beautiful website! No bullshit, high utility, zero tracking. As it should be!


Thanks!


Is there something like this for car tires?


Kind of similar: https://tiresize.com/calculator/

I've used it for buying my truck's tires in the past.




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