44 ms·

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 ma

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.

moasda 5y ago
Thanks a lot for the insights!
- mauvehaus 5y ago
  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.
timonoko 5y ago
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.
- timonoko 5y ago
  Apropos: Mericans would then say I have "700c" or "28 inch" in front and "29 inch" in back.
- mauvehaus 5y ago
  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.
- PascLeRasc 5y ago
  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.
  - timonoko 5y ago
    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.
droidno9 5y ago
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.
- mauvehaus 5y ago
  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.
  - walrus01 5y ago
    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-gravel-and-adventure-tyres-you-can-buy-tried-and-tested-in-the https://off.road.cc/content/buying/13-of-the-best-650b-grave... https://granfondo-cycling.com/650b-vs-700c/ 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.
    - sasawpg 5y ago
      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.
timonoko 5y ago
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.
hunter2_ 5y ago
> 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?
- pythonaut 5y ago
  The mm widths refer to exact rim diameter while the inch measurements refer to rim+tire diameter and are not exact.
  - mauvehaus 5y ago
    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.
- walrus01 5y ago
  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"
- zwog 5y ago
  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 )
walrus01 5y ago
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-Performance/dp/B07K8XN48B?th=1&psc=1 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+profile&client=firefox-b-1-d&sxsrf=APq-WBvilLnmnrXAoaNEtxqVTxEsj1n29g:1643587056721&source=lnms&tbm=isch&sa=X&ved=2ahUKEwje9bD11tr1AhXSKH0KHXMzCSsQ_AUoAnoECAEQBA&biw=1680&bih=940&dpr=2 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.
buzzard1 5y ago
mikeryan 5y ago
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.
- walrus01 5y ago
  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.
  - IgorPartola 5y ago
    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?
    - sasawpg 5y ago
      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.
ho_schi 5y ago
Schwalbe offers a good general overview: https://www.schwalbe.com/en/groessenbezeichnung 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/ https://www.schwalbe.com/technik-faq/ # german

moasda 5y ago

Thanks a lot for the insights!

mauvehaus 5y ago
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.

timonoko 5y ago

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.

timonoko 5y ago
Apropos: Mericans would then say I have "700c" or "28 inch" in front and "29 inch" in back.
mauvehaus 5y ago
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.
PascLeRasc 5y ago
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.
- timonoko 5y ago
  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.

droidno9 5y ago

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.

mauvehaus 5y ago
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.
- walrus01 5y ago
  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-gravel-and-adventure-tyres-you-can-buy-tried-and-tested-in-the https://off.road.cc/content/buying/13-of-the-best-650b-grave... https://granfondo-cycling.com/650b-vs-700c/ 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.
  - sasawpg 5y ago
    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.

timonoko 5y ago

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.

hunter2_ 5y ago

> 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?

pythonaut 5y ago
The mm widths refer to exact rim diameter while the inch measurements refer to rim+tire diameter and are not exact.
- mauvehaus 5y ago
  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.
walrus01 5y ago
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"
zwog 5y ago
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 )

walrus01 5y ago

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-Performance/dp/B07K8XN48B?th=1&psc=1 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+profile&client=firefox-b-1-d&sxsrf=APq-WBvilLnmnrXAoaNEtxqVTxEsj1n29g:1643587056721&source=lnms&tbm=isch&sa=X&ved=2ahUKEwje9bD11tr1AhXSKH0KHXMzCSsQ_AUoAnoECAEQBA&biw=1680&bih=940&dpr=2 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.

buzzard1 5y ago

mikeryan 5y ago

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.

walrus01 5y ago
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.
- IgorPartola 5y ago
  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?
  - sasawpg 5y ago
    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.

ho_schi 5y ago

Schwalbe offers a good general overview: https://www.schwalbe.com/en/groessenbezeichnung 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/ https://www.schwalbe.com/technik-faq/ # german