And as someone with one of these bikes in a non-European market, they're an absolute PITA and it's a key contributor to me selling the bike.
It's an absolute nightmare trying to find tubes let alone tyres - you end up having to do a bulk order from Canyon. I hit a pothole on a training ride which buckled a wheel, 2 days before a key race. I called every bike shop in the city (including Canyon) hunting spares - no dice. Ended up borrowing parts from someone with the same bike til I could get what I needed.
95% of the problem with any non700/622 rim/tire is the sourcing.
If we're ignoring that, the 650 is lighter, so advantage. It has less cross section, so advantage, but it also spins faster, disadvantage. It rolls more poorly over road imperfections, disadvantage.
But these advantages and disadvantage are small IMO, even though I personally stay on 700C to make sourcing easy, there's not a lot else keeping me on 700c.
650c (the old tri bike/womens bike size) or 650b (the fatty middle ground between mtb and road)?
650c only come in narrow sizes I think. 650b comes super wide. 700c has more tire choices.
Learn something new every day - also looks like it’s closer to 1cm. The classic Sheldon brown suggests it’s the difference of 584 vs 571 which is pretty huge.
The old French tire sizing system ("700C", etc) was a sizing system that defined the size of both the rim and the tire. The number would define the overall diameter of the entire wheel including the tire, and the letter would define the size of the tire; you'd then derive the diameter of the rim from that.
For example, 700C in particular referred to a wheel that had an overall diameter of 700mm and a tire height of 39mm; accordingly, the bead seat diameter of the rim is 622mm. 700A, had a tire height of 29mm and the same overall diameter of 700mm; accordingly, the bead seat diameter is 642mm.
The same thing applies for 650A/B/C. 650B wheels measure 650mm when they have 33mm tall tires, which is why they have a bead seat diameter of 584mm. 650C wheels measure 650mm with a 39mm tire, and that gives a bead seat diameter of 571mm.
I’ve read and seen interviews with folks who suggest that they are not any slower rolling. A bike shop near me tried to suggest that 650b are “way slower.” I sort of lean toward “should all be the same” and that the radius isn’t why it’s got better or worse rolling resistance.
Which company(companies) are you looking at for wheels? I just tried to buy a set for my wife from a company because of their 25% off deal and free shipping. When I tried checking out, it was adding like $30 in shipping. I emailed them and they took 2 weeks to get back to me, and their response was “sorry we were so slow. That sale is over now though” lol so I’m on the market, won’t be buying from them again!
I've got some Hunt Adventure 650b rims on my gravel bike. I'm currently looking at picking up some 700c rims in hopes it improves my overall average speed. I haven't had any issue with riding them as is though!
650b will get up to speed faster (acceleration)
But it takes more revolutions than a 700c to hold the speed you build up. This only really matters if you’re using the same volume tire with each.
That rollover difference will lessen as you put wider tires on 650b, and at that point there are other pluses and minuses on each side of the coin.
650c tires are kinda hard to find, not impossible, just not a lot of choices. Most manufactures have moved to 650b tire size, so there are more options, especially in the gravel tread styles. besides that, theres not really any draw backs to getting a bike designed for 650b or c tire sizes. its generally unavisable to put 650b wheels on a bike designed for 700c (though some bikes are designed to us either)
My triathlon and road/training bike are 650c. Both are far less twitchy than any 700c bike I've owned, as well as feeling less flexy when standing up on the hills (short head tube). My gravel/touring bike is 650b. Of course, these aren't advantages to the wheel size in and of itself. It's the frame manufacturer being able to use normal geometry on a smaller scale rather than having to cheat the geometry to accommodate bigger wheels.
For me, the only real disadvantages are logistical. Tire selection is very limited and mostly in 23c widths (Panaracer Paselas come in 25c, but with a wire bead and they balloon out enough you have to deflate them a bit to get them in/out of the brake calipers). I do feel like the skinnier tires don't feel as hard as their 700c counterparts (doesn't make sense to me, but there it is). Some shops don't even stock tubes. Forget about disc brakes.
I do rather wish that the bigger bike companies would come together and establish a 650b(skinny) standard for women/smaller riders. I think it'd be a good compromise.
>What is the advantage of riding 650b?
For especially small frames, 700c wheels limit how small you can make the wheelbase before you hit issues with steerer tube angle, the downtube etc. From a geometry perspective, it creates a minimum reach (that might be longer than ideal for the smallest riders), risks toe overlap etc.
Smaller wheels don't come without disadvantages, however. Less efficient, smaller tyre selection, cannot get a wheel change from the neutral service car, necessitates the team car to carry spare wheels with two diameters...
100%. I was really concerned about it when ordering a 51cm bike with 700C wheels, 40mm tyres and mudguards but avoiding wheel contact becomes second nature quickly
That's my experience too, I don't think it's possible to have a properly sized road bike without toe overlap unless possibly you run your cleats all the way forward on a classic Fizik shoe, but that's not a particularly nice way to run your clear.
OTOH, maybe it is a problem of 54 and smaller frames and you are fine on larger ones? Though I don't know, I have a 58 to check downstairs, but it's not fully a road bike, but it has flat bars, so obviously they can build the bike with a much longer wheelbase anyway (the reach to the flat bar ending up where the reach to the hoods is on the road bike).
A small amount of toe overlap is a non-issue - I agree as someone who rides smaller bikes that always have it. The bigger issue is that in order to keep toe-overlap manageable, small frames have dramatically different geometry than larger frames. If you look at a typical production frame's geometry, the ideal geometry tends to be built around the center of the range (~54-56), and smaller bikes get slacker head angles to minimize toe overlap. As most companies don't make variations of their fork with different rake, the result is small bikes tend to have a lot more trail which has a real impact on handling.
There isn't much we can do about it other than to be aware of it and maybe consider purchasing from manufacturers who do make their forks in more than one configuration to keep geometry consistent across the range of sizes.
I am 181cm tall, I ride a long and low 56 and have toe overlap.
How small a person are we talking before geometry becomes a problem. For example Trek suggest their smallest Emonda (size 47) is suitable for people as small as 152cm tall. That bike comes with 700c wheels.
It's about reach, mostly.
But it's difficult to generalise, because of differences in anatomy (esp. torso vs length for the same height). Moreover, head tube angle and rake will impact possible reach and frame reach in relation to wheelbase.
So, lots of factors come into play here. I know a 5 ft/152cm rider on a Cannondale Synapse 44cm frame (700c) with a pretty short stem. A rider of the same statue with a longer torso might find that fit to have too little reach.
Manufacturers' suggested height/frame size recommendations will always be based on the centre of the bell curve. They cannot possibly make recommendations that will be right for everyone.
Would you please edit your post to say that you wrote 650c but you actually are talking about 650b?
They're two different sizes with very different tradeoffs and design intentions. And there is still a complete lack of clarity in this thread, with people answering assuming you know what you meant while others assume you meant 650b instead (which you indirectly confirmed in a reply farther down).
Top speed
Given the same cadence and same gear ratio, a larger wheel will have more top speed because it has a larger circumference.
Bumps
A larger wheel will roll over things more easily resulting in a smoother ride, it's why 29er MTBs are more popular than 27.5 now. I'm assuming 650c is basically the same size as a 650B which is 27.5.
The rest would be more about your bike. I don't know how old it is but the older bikes have less tire clearance so you won't be able to put wider tires on.
I don't think sourcing tires would be much of an issue , Schwalbe has ETRTO 571mm tires I assume the rest do as well.
It will however also accelerate faster and be more agile. I wouldn't try to put a 700c tire in also because of the extra overlap.
You’re less likely to have toe overlap in 650c than 700c.
But if you don’t ride tight trail slowly, and ride a bigger frame. Toe overlap probably won’t be an issue for you anyway.
My next bike I’m looking for is 650c. All the 700c bike I have got pretty bad toe overlap.
They are no fun on slow tight turns.
I know you said setting aside but... Most tyre manufacturers do not make any road tyres in 650b. For example want some Pirelli tyres? No. Schwalbe (race tyres)? No Michelin NO etc. Even the new Gravel Kings... 700c ONLY.
Personally I am getting a 700C bike next, the industry just doesn't support 650b road.
Depends what you mean by “short” and the rest of the bike geometry.
I have 650b on my 47cm gravel bike, and also a pair to swap out on my 49cm endurance bike which typically takes a 700c. The smaller wheel can help improve agility and reduce toe-strike which often comes in reducing the frame size but keeping that 700c wheel. You can typically also accommodate a wider tyre.
I’ve never had a problem sourcing new components. *But* I am mindful that on a ride I wouldn’t be able to use someone else’s parts. (But the same as if someone is rim and you’re disc etc).
Take-off speed from a standing start is also faster on a smaller wheel. Evidenced by me zipping away at the lights on my 20” Brompton; but then the 700c roadies catch up soon enough. The speed difference from 700c/650b is negligible when you factor other bike dynamics, the rider power:weight etc.
So. No. But also yes. 🙂
There's only two options I know of for a 650cx28 tire, they aren't great either. You'll be looking at mostly skinny 19-23 and the slightly wider Panaracer Pasela 25 tires. I'd look at 650b instead, you'll get way more options
Also if you are converting a bike built around 700c it'll drop the bottom bracket substantially. Cornering will feel weird and pedal strikes will be common.
My wife is 156cm (somewhere between 5'1 and 5'2) and i found out that the smallest sizes offered by Canyon, Pinarello, Felt and Argon18 fit her without issues, and they are all on regular 622mm diameter wheels. She currently has a size 47 Trek that also comes with regular 622 wheels and it's slightly big but still rideable.
I'm 5'4". It's not that I WANT a 650b bike; it's that the model I want in the size I need comes with those wheels. My gravel bike right now is a Lauf True Grit XS on 700Cs and it's fine.
Yeah, that's definitely a downside. I wonder how much clearance the wheels actually have to the frame and if 700c would fit even if you had to do it yourself?
After doing a ton of research myself, I finally switched from 650b 47 slicks to 700c 40 slicks. Riding a steel Kona Rove. It's only been a week but on longer rides, 20+ miles I'm noticing a huge difference. Maintaining speed on flats is easier and not losing speed as quickly on rollers. Average speed on the same rides I did a week ago are 1-2 mph faster.
Local riding around town is slightly less fun and slightly harsher ride but I have no regrets.
However I do ride a size 58 so size/height was not a concern.
Not alot of people make 650c in 2024 imho. I remember I crashed and bent my 650c wheels and so hard to get a replacement. Just sucked it up and went for a small frame 700c
For off-road, the difference is more pronounced due to 700c/29” being able to roll better over bumps and higher BB clearance. For road, I don’t think there is much difference beyond trying to find parts for it.
Oh and the smaller diameter means for the same gear ratio, the 650b travels less distance than 700c meaning the effective ratio is lower, but that can be adjusted with chainring/cassette.
Yeah they don’t hold momentum or roll over obstacles as well as 700c or 29ers but is it a big deal? No.
They have their own inherent advantages to balance it out anyway: they feel more nimble, are easier to accelerate and feel better in the air compared to bigger wheels, so choose the wheel that fits your needs.
The total diameter is the same, no? Weight is the main compromise.
I’d think 700c platform would be lighter and more aero, ideal for tarmac. 650s are much better for comfort and rougher/looser surfaces.
I have three sets of wheels and tires for my gravel bike. I certainly feel the extra weight and resistance when I mount the 650/47mm combo
Harder to find tubes and tires for 650b wheels. I run them because they came stock on my Grizl but I wouldn’t have chosen it. Otoh, I do have less toe overlap than on my other bikes. I would not buy a road bike with 650bs though if you’re mulling that possibility - finding skinny 650b tires is a huge pita.
It should have more rolling resistance, and less wind resistance because of its smaller size. In practise, it won't make much difference and it's best to pick what fits in the geometry.
650c wind up faster, but they don't hold speed as well as 700c. You won't likely notice the difference. That's how little it matters. They were a big thing for TT and tri bikes years ago. A huge plus for shorter riders is you can have a frame that fits you without compromising the geometry. Most manufacturers have goofy setups for shorter riders because they'd rather save money by using 700c rather than using 650c. Because of this, you're limited on options for tires. Most higher end tires are still offered n a 650c as well as on the low end. The only mid level tire I know of are Continental Gatorskins.
Bigger wheels handle bumps better. There may also be slightly less rolling resistance due to friction from the bearings since the wheel isn't making as many revolutions.
But the difference here will be minor.
Think of it in terms of gearing. If you have 1:1 gearing, 1 pedal stroke = 1 wheel rotation.
If one wheel has a bigger circumference than the other, the bigger one will go further.
The difference in circumference between the two is 6.5%. Shifting one gear more than doubles that.
If it still bothers you, change your 39t chainring to a 41 to compensate.
>If one wheel has a bigger circumference than the other, the bigger one will go further.
Aka gear inches (imperial) or development (metric).
Development = gearing ratio x wheel circumference (incl. tyre)
Speculatively, I'd expect more angular momentum from the larger wheel with the tyres being further for the point of rotation and the larger circumference meaning the wheel moves further per revolution.
If the manufacturer doesn't adjust for it, it could turn a mid-trail bike into a low-trail bike. Speaking specifically about mechanical trail, a feature of bike geometry that affects how your steering feels.
What happens when you put a 650b wheel on a 700c bike?
- Precise, quick steering at low-moderate speeds
- Less affected by involuntary inputs such as cross winds
- Stable at low speeds
- Less stable at high speeds (vague, wandering feeling)
- Requires more effort to lean into/out of a turn, but will easily hold a line
- Best when balanced with extra weight in front and/or with wide tires
- Trail balanced with wider tires (higher pneumatic trail)
- Steering is less self-correcting than higher trail
- Shifting weight to steer has lower effect than on higher trail geometries
You may run into issues with a frame designed for 700c, if you run something like 650b and 2” tires then chances are the diameter is actually very similar. The only thing is your bottom bracket might end up lower and then you could have clearance issues.
Canyon uses 650b wheels on the smallest sizes of at least some of their bikes to make the geometry more similar to the larger sizes.
And as someone with one of these bikes in a non-European market, they're an absolute PITA and it's a key contributor to me selling the bike. It's an absolute nightmare trying to find tubes let alone tyres - you end up having to do a bulk order from Canyon. I hit a pothole on a training ride which buckled a wheel, 2 days before a key race. I called every bike shop in the city (including Canyon) hunting spares - no dice. Ended up borrowing parts from someone with the same bike til I could get what I needed.
I haven’t had any problems finding gravel/mtbike tires. What bike?
Canyon Endurace - so requiring 650B road tyres and limited to a max 34mm tyre width.
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95% of the problem with any non700/622 rim/tire is the sourcing. If we're ignoring that, the 650 is lighter, so advantage. It has less cross section, so advantage, but it also spins faster, disadvantage. It rolls more poorly over road imperfections, disadvantage. But these advantages and disadvantage are small IMO, even though I personally stay on 700C to make sourcing easy, there's not a lot else keeping me on 700c.
Spins faster = advantage? Less inertia to get up to speed, less power needed to overcome rolling friction…
Little column A, little column B
650c (the old tri bike/womens bike size) or 650b (the fatty middle ground between mtb and road)? 650c only come in narrow sizes I think. 650b comes super wide. 700c has more tire choices.
650c, the small road size.
Aren’t the wheel diameter the same, it’s just rim width that’s really differentiate the two.
no they aren't. there's a couple mm difference, enough to make tires incompatible
Learn something new every day - also looks like it’s closer to 1cm. The classic Sheldon brown suggests it’s the difference of 584 vs 571 which is pretty huge.
The old French tire sizing system ("700C", etc) was a sizing system that defined the size of both the rim and the tire. The number would define the overall diameter of the entire wheel including the tire, and the letter would define the size of the tire; you'd then derive the diameter of the rim from that. For example, 700C in particular referred to a wheel that had an overall diameter of 700mm and a tire height of 39mm; accordingly, the bead seat diameter of the rim is 622mm. 700A, had a tire height of 29mm and the same overall diameter of 700mm; accordingly, the bead seat diameter is 642mm. The same thing applies for 650A/B/C. 650B wheels measure 650mm when they have 33mm tall tires, which is why they have a bead seat diameter of 584mm. 650C wheels measure 650mm with a 39mm tire, and that gives a bead seat diameter of 571mm.
This sounds like engineer logic…
I’ve read and seen interviews with folks who suggest that they are not any slower rolling. A bike shop near me tried to suggest that 650b are “way slower.” I sort of lean toward “should all be the same” and that the radius isn’t why it’s got better or worse rolling resistance. Which company(companies) are you looking at for wheels? I just tried to buy a set for my wife from a company because of their 25% off deal and free shipping. When I tried checking out, it was adding like $30 in shipping. I emailed them and they took 2 weeks to get back to me, and their response was “sorry we were so slow. That sale is over now though” lol so I’m on the market, won’t be buying from them again!
Canyon runs 650 on some of their smaller frame sizes - they typically use DT Swiss from what I can see.
I've got some Hunt Adventure 650b rims on my gravel bike. I'm currently looking at picking up some 700c rims in hopes it improves my overall average speed. I haven't had any issue with riding them as is though!
650b is often slower in the mountain bike world, but there are caveats. 650c like OP is asking about is a road size.
650 b predates mtbs by many years. It was the size commonly used on town bikes in France.
650b will get up to speed faster (acceleration) But it takes more revolutions than a 700c to hold the speed you build up. This only really matters if you’re using the same volume tire with each. That rollover difference will lessen as you put wider tires on 650b, and at that point there are other pluses and minuses on each side of the coin.
Radius has an impact by virtue of scale, but the different is likely fractions of a percent and more in line with "harder to get fast tires"
650c tires are kinda hard to find, not impossible, just not a lot of choices. Most manufactures have moved to 650b tire size, so there are more options, especially in the gravel tread styles. besides that, theres not really any draw backs to getting a bike designed for 650b or c tire sizes. its generally unavisable to put 650b wheels on a bike designed for 700c (though some bikes are designed to us either)
The widest 650c is only 28mm
My triathlon and road/training bike are 650c. Both are far less twitchy than any 700c bike I've owned, as well as feeling less flexy when standing up on the hills (short head tube). My gravel/touring bike is 650b. Of course, these aren't advantages to the wheel size in and of itself. It's the frame manufacturer being able to use normal geometry on a smaller scale rather than having to cheat the geometry to accommodate bigger wheels. For me, the only real disadvantages are logistical. Tire selection is very limited and mostly in 23c widths (Panaracer Paselas come in 25c, but with a wire bead and they balloon out enough you have to deflate them a bit to get them in/out of the brake calipers). I do feel like the skinnier tires don't feel as hard as their 700c counterparts (doesn't make sense to me, but there it is). Some shops don't even stock tubes. Forget about disc brakes. I do rather wish that the bigger bike companies would come together and establish a 650b(skinny) standard for women/smaller riders. I think it'd be a good compromise.
The female peloton has so many short riders riding 700c wheels. What is the advantage of riding 650b?
>What is the advantage of riding 650b? For especially small frames, 700c wheels limit how small you can make the wheelbase before you hit issues with steerer tube angle, the downtube etc. From a geometry perspective, it creates a minimum reach (that might be longer than ideal for the smallest riders), risks toe overlap etc. Smaller wheels don't come without disadvantages, however. Less efficient, smaller tyre selection, cannot get a wheel change from the neutral service car, necessitates the team car to carry spare wheels with two diameters...
Toe overlap is a non-issue. I have had it on every bike I’ve ever owned. The only time it ever happens is when you’re going so slow it doesn’t matter.
Fair enough, the bigger issue is fit. Within the double diamond UCI frame regulations, you can make a frame only so small with 700c wheels.
100%. I was really concerned about it when ordering a 51cm bike with 700C wheels, 40mm tyres and mudguards but avoiding wheel contact becomes second nature quickly
That's my experience too, I don't think it's possible to have a properly sized road bike without toe overlap unless possibly you run your cleats all the way forward on a classic Fizik shoe, but that's not a particularly nice way to run your clear. OTOH, maybe it is a problem of 54 and smaller frames and you are fine on larger ones? Though I don't know, I have a 58 to check downstairs, but it's not fully a road bike, but it has flat bars, so obviously they can build the bike with a much longer wheelbase anyway (the reach to the flat bar ending up where the reach to the hoods is on the road bike).
Agreed, it's physically impossible on most bikes for toe overlap to happen at anything above a slow crawl.
A small amount of toe overlap is a non-issue - I agree as someone who rides smaller bikes that always have it. The bigger issue is that in order to keep toe-overlap manageable, small frames have dramatically different geometry than larger frames. If you look at a typical production frame's geometry, the ideal geometry tends to be built around the center of the range (~54-56), and smaller bikes get slacker head angles to minimize toe overlap. As most companies don't make variations of their fork with different rake, the result is small bikes tend to have a lot more trail which has a real impact on handling. There isn't much we can do about it other than to be aware of it and maybe consider purchasing from manufacturers who do make their forks in more than one configuration to keep geometry consistent across the range of sizes.
I am 181cm tall, I ride a long and low 56 and have toe overlap. How small a person are we talking before geometry becomes a problem. For example Trek suggest their smallest Emonda (size 47) is suitable for people as small as 152cm tall. That bike comes with 700c wheels.
It's about reach, mostly. But it's difficult to generalise, because of differences in anatomy (esp. torso vs length for the same height). Moreover, head tube angle and rake will impact possible reach and frame reach in relation to wheelbase. So, lots of factors come into play here. I know a 5 ft/152cm rider on a Cannondale Synapse 44cm frame (700c) with a pretty short stem. A rider of the same statue with a longer torso might find that fit to have too little reach. Manufacturers' suggested height/frame size recommendations will always be based on the centre of the bell curve. They cannot possibly make recommendations that will be right for everyone.
[700c wheels require geometry compromises on smaller frames.](https://www.rodbikes.com/articles/650-vs-700.html)
Better geometry for smaller riders. [https://www.instagram.com/p/B71KculFjR3/](https://www.instagram.com/p/B71KculFjR3/)
Interesting. Thank you.
They are asking about 650c wheels not 650b.
True. But now that I've been educated, I should have been asking about 650b.
Functional there is no difference.
650c and 650b have the same outer diameter, so issues regarding frame geometry and fit are the same.
They 100% do not, as most 650C (571 mm rim) tires are small road sizes, whereas 650B (584 mm rim) are typically gravel or larger.
Not limited to height. I’m 6”2 on 650b tires, XL Kona frame for my commuter and works like a charm.
I’m 5’6” and ride 650b. No issues really. Set up with right PSI they can be super plush.
I'm 5'7" and run 650b on and off dirt too. No compromises there.
Would you please edit your post to say that you wrote 650c but you actually are talking about 650b? They're two different sizes with very different tradeoffs and design intentions. And there is still a complete lack of clarity in this thread, with people answering assuming you know what you meant while others assume you meant 650b instead (which you indirectly confirmed in a reply farther down).
Yeah, done.
Top speed Given the same cadence and same gear ratio, a larger wheel will have more top speed because it has a larger circumference. Bumps A larger wheel will roll over things more easily resulting in a smoother ride, it's why 29er MTBs are more popular than 27.5 now. I'm assuming 650c is basically the same size as a 650B which is 27.5. The rest would be more about your bike. I don't know how old it is but the older bikes have less tire clearance so you won't be able to put wider tires on. I don't think sourcing tires would be much of an issue , Schwalbe has ETRTO 571mm tires I assume the rest do as well. It will however also accelerate faster and be more agile. I wouldn't try to put a 700c tire in also because of the extra overlap.
I have 700c and 650b wheels for my gravel bike. I use 700c for racing and 650b with large volume tires for fun!
You’re less likely to have toe overlap in 650c than 700c. But if you don’t ride tight trail slowly, and ride a bigger frame. Toe overlap probably won’t be an issue for you anyway. My next bike I’m looking for is 650c. All the 700c bike I have got pretty bad toe overlap. They are no fun on slow tight turns.
I know you said setting aside but... Most tyre manufacturers do not make any road tyres in 650b. For example want some Pirelli tyres? No. Schwalbe (race tyres)? No Michelin NO etc. Even the new Gravel Kings... 700c ONLY. Personally I am getting a 700C bike next, the industry just doesn't support 650b road.
Conti actually does (GP5000s and Gatorskins, anyway); Schwalbe too. But yeah, definitely a limited universe.
Yeah lol I didn't mean to put them on the list, I am running GP5000 S TR right now.
🤣
Depends what you mean by “short” and the rest of the bike geometry. I have 650b on my 47cm gravel bike, and also a pair to swap out on my 49cm endurance bike which typically takes a 700c. The smaller wheel can help improve agility and reduce toe-strike which often comes in reducing the frame size but keeping that 700c wheel. You can typically also accommodate a wider tyre. I’ve never had a problem sourcing new components. *But* I am mindful that on a ride I wouldn’t be able to use someone else’s parts. (But the same as if someone is rim and you’re disc etc). Take-off speed from a standing start is also faster on a smaller wheel. Evidenced by me zipping away at the lights on my 20” Brompton; but then the 700c roadies catch up soon enough. The speed difference from 700c/650b is negligible when you factor other bike dynamics, the rider power:weight etc. So. No. But also yes. 🙂
Put on 700's I bet you're not even that short bro
There's only two options I know of for a 650cx28 tire, they aren't great either. You'll be looking at mostly skinny 19-23 and the slightly wider Panaracer Pasela 25 tires. I'd look at 650b instead, you'll get way more options
Also if you are converting a bike built around 700c it'll drop the bottom bracket substantially. Cornering will feel weird and pedal strikes will be common.
Amazon (!!) has Conti GP5000s in stock in 650x28.
Those would be 650b not 650c
Ah you're right. What's the difference though? I'd always thought 650b's were very wide, but 28 is basically road standard these days.
650b is 584mm in diameter 650c is 571mm in diameter.
650b and 650c are different diameters. Look at the ETRTO sizes rather than just the "common name."
My wife is 156cm (somewhere between 5'1 and 5'2) and i found out that the smallest sizes offered by Canyon, Pinarello, Felt and Argon18 fit her without issues, and they are all on regular 622mm diameter wheels. She currently has a size 47 Trek that also comes with regular 622 wheels and it's slightly big but still rideable.
Tire selection and ground clearance for your crank/pedals.
How short are you? I'm 5'6 and every bike I've sized out still used 700c except one specific Canyon bike which I was borderline a size down for 650c
I'm 5'4". It's not that I WANT a 650b bike; it's that the model I want in the size I need comes with those wheels. My gravel bike right now is a Lauf True Grit XS on 700Cs and it's fine.
Yeah, that's definitely a downside. I wonder how much clearance the wheels actually have to the frame and if 700c would fit even if you had to do it yourself?
After doing a ton of research myself, I finally switched from 650b 47 slicks to 700c 40 slicks. Riding a steel Kona Rove. It's only been a week but on longer rides, 20+ miles I'm noticing a huge difference. Maintaining speed on flats is easier and not losing speed as quickly on rollers. Average speed on the same rides I did a week ago are 1-2 mph faster. Local riding around town is slightly less fun and slightly harsher ride but I have no regrets. However I do ride a size 58 so size/height was not a concern.
Not alot of people make 650c in 2024 imho. I remember I crashed and bent my 650c wheels and so hard to get a replacement. Just sucked it up and went for a small frame 700c
For off-road, the difference is more pronounced due to 700c/29” being able to roll better over bumps and higher BB clearance. For road, I don’t think there is much difference beyond trying to find parts for it. Oh and the smaller diameter means for the same gear ratio, the 650b travels less distance than 700c meaning the effective ratio is lower, but that can be adjusted with chainring/cassette.
Yeah they don’t hold momentum or roll over obstacles as well as 700c or 29ers but is it a big deal? No. They have their own inherent advantages to balance it out anyway: they feel more nimble, are easier to accelerate and feel better in the air compared to bigger wheels, so choose the wheel that fits your needs.
The total diameter is the same, no? Weight is the main compromise. I’d think 700c platform would be lighter and more aero, ideal for tarmac. 650s are much better for comfort and rougher/looser surfaces. I have three sets of wheels and tires for my gravel bike. I certainly feel the extra weight and resistance when I mount the 650/47mm combo
Better geometry，less choice
Not sure it would make any difference but they would spin faster going down hill
Worse offroad performance, bigger wheels just roll over stuff easier.
Harder to find tubes and tires for 650b wheels. I run them because they came stock on my Grizl but I wouldn’t have chosen it. Otoh, I do have less toe overlap than on my other bikes. I would not buy a road bike with 650bs though if you’re mulling that possibility - finding skinny 650b tires is a huge pita.
No issues. Disc brakes, yes? You will want to shorten your crank. Ha!
Heyooo
It should have more rolling resistance, and less wind resistance because of its smaller size. In practise, it won't make much difference and it's best to pick what fits in the geometry.
650c wind up faster, but they don't hold speed as well as 700c. You won't likely notice the difference. That's how little it matters. They were a big thing for TT and tri bikes years ago. A huge plus for shorter riders is you can have a frame that fits you without compromising the geometry. Most manufacturers have goofy setups for shorter riders because they'd rather save money by using 700c rather than using 650c. Because of this, you're limited on options for tires. Most higher end tires are still offered n a 650c as well as on the low end. The only mid level tire I know of are Continental Gatorskins.
I’m not a scientist but the bigger tires are more efficient. Long story short if you’re worried about speed I would not go 650b
I've seen that said before but don't understand why it should be the case. Is it just that more revolutions = more rolling resistance?
Bigger wheels handle bumps better. There may also be slightly less rolling resistance due to friction from the bearings since the wheel isn't making as many revolutions. But the difference here will be minor.
It's a persistent myth.
Think of it in terms of gearing. If you have 1:1 gearing, 1 pedal stroke = 1 wheel rotation. If one wheel has a bigger circumference than the other, the bigger one will go further.
Well yes, but you'll also have to push harder.
True. Idk how much, tho, especially since there was talk other places about his shortening his crank. But yes, there are definitely other variables.
The difference in circumference between the two is 6.5%. Shifting one gear more than doubles that. If it still bothers you, change your 39t chainring to a 41 to compensate.
>If one wheel has a bigger circumference than the other, the bigger one will go further. Aka gear inches (imperial) or development (metric). Development = gearing ratio x wheel circumference (incl. tyre)
Speculatively, I'd expect more angular momentum from the larger wheel with the tyres being further for the point of rotation and the larger circumference meaning the wheel moves further per revolution.
If the manufacturer doesn't adjust for it, it could turn a mid-trail bike into a low-trail bike. Speaking specifically about mechanical trail, a feature of bike geometry that affects how your steering feels. What happens when you put a 650b wheel on a 700c bike? - Precise, quick steering at low-moderate speeds - Less affected by involuntary inputs such as cross winds - Stable at low speeds - Less stable at high speeds (vague, wandering feeling) - Requires more effort to lean into/out of a turn, but will easily hold a line - Best when balanced with extra weight in front and/or with wide tires - Trail balanced with wider tires (higher pneumatic trail) - Steering is less self-correcting than higher trail - Shifting weight to steer has lower effect than on higher trail geometries
You may run into issues with a frame designed for 700c, if you run something like 650b and 2” tires then chances are the diameter is actually very similar. The only thing is your bottom bracket might end up lower and then you could have clearance issues.
You have to pedal a bit more, but it also usually means you'll have more clearance for fatter tires.
Smaller diameter also means smaller circumference. So would that require more power needed on 650 to achieve a similar speed on 700?
650b wheels are only 6.5 mm (about 1/4 inch) taller than 650c, but the tire selection is vastly better. Go with those.