[Closed] So why don't they make road bike wheels bigger?

I thought it was to do with rolling over obstacles/stones and that? Not much of that on't road..

Should make them smaller then.

No. The advantage of big wheels is that they don't fall so far into a hole. On the road (hopefully) there are no holes, so wheel size doesn't matter.

In fact, as Moultons have shown for years, on roads small wheels are faster - they're lighter, stiffer and more aerodynamic. Assuming tyres are the same, wheel size doesn't matter.

They did didn't they?

[IMG] :original[/IMG]

That was before someone invented gearing 😉

I thought it was to do with rolling over obstacles/stones and that? Not much of that on't road..

You should try riding down my way...

😀

They would if they could but there comes a point where you just can't package a larger wheel under the rider without compromising geometry and other aspects of the machine.

In fact, as Moultons have shown for years, on roads small wheels are faster - they're lighter, stiffer and more aerodynamic.

Is that why Wiggins did so well on his Brompton?

Is that why Wiggins did so well on his Brompton?

He was constrianed by the UCI's daft rules - on a Moulton, he'd have been faster. Not a Brompton - that's a city bike.

there comes a point where you just can't package a larger wheel under the rider without compromising geometry and other aspects of the machine.

They used to.

My pub bike has 27" wheels, which are bigger than 700c.

Even though 700c road tyres are nominally 28" and as any fule kno 700c MTB tyres are 29"

[i]on a Moulton, he'd have been faster[/i]

Seriously? Why/how?

i thought it was something like small wheels accelerate faster large wheels maintain speed better

then theres strength to weight, big wheel needs stronger components thus lightweight = more expensive...

its all a comprimise

He was constrianed by the UCI's daft rules - on a Moulton, he'd have been faster

They would if they could but there comes a point where you just can't package a larger wheel under the rider without compromising geometry and other aspects of the machine.

Toe overlap anyone? Try riding a bike that's a size or two too small for you (hence inevitably designed for people with smaller feet too) and you'll see what I mean. Had to ride a friends 50cm ladies road bike the other day up and down the road to diagnose a problem. Firstly, I couldn't pedal anything but a complete straight line with clipping my toes on the front wheel!

Moultons were raced, back in the day, but never caught on for some reason

Still are, as are recumbents. All banned by the UCI, even though they're faster and safer. The road bike shape is based on a rose-tinted view of bicycles perpetrated by a bunch of suits who are more happy to see riders take drugs than allow any technological advance.

Really, it's only a small step away from making Wiggo ride a penny farthing.

Is that "larger wheels maintain momentum better" true but a bit of a red herring, as the extra momentum has come from the additional energy the rider has to input to get them to the same speed as a smaller lighter wheel?

Yes, the momentum is negligible, and not really a benefit - it makes the steering sluggish. The momentum it maintains is the momentum of the entire bike/rider system offroad, over rough terrain.

I still don't understand why 26" wheels are no good all of a sudden...

I still don't understand why 26" wheels are no good all of a sudden...

They never were, they were just what was available with ~2" tyres 30 years ago.

They've not gotten worse, someone just figured out that 29" was better.

Bit like suspension forks are better than rigid forks, but rigid forks haven't gotten any worse (plenty of people still use them). The difference is there aren't the same maintenance and cost issues with 29ers as suspension.

Smaller wheels are better on the road as they're more aerodynamic IIRC.

and they figured that out about 30 years ago, but couldn't get the tyres.

it's not that 26" wheels are suddenly 'no good', they're as good as they ever were.

but, lots of people are finding that they like 29" wheels more, without any significant disadvantages.

Seriously? Why/how?

smaller wheels are lighter, and more aerodynamic, and at tdf speeds that's hugely important.

and they figured that out about 30 years ago, but couldn't get the tyres.

I find that amazing that "they" whoever they were couldn't develop or fund the construction a larger carcass building drum and curing mold for a larger bike tyre. Wow

We have had on occasion private individuals with their own molds approaching us to build small production runs. I find it utterly unbelievable that this couldnt have been done 30 years ago. The fundamental construction process is very much the same as it was back then.

They've not gotten worse, someone just figured out that 29" was [s]better[/s]different.

FTFY

or, it was just much, much easier to go with 26" wheels, as the rims and tyres were (relatively) easily available, and there's not really all that much difference if we're being honest.

really, the difference between 26" and 29" is quite small, it feels like a few psi difference in the tyres.

it's not enough to justify making your own tyres, but is enough to justify trying to see if you like it/or not, or can even notice the difference/or not.

They've not gotten worse, someone just figured out that 29" was [s]betterdifferent[/s]lucrative.

Double edit 🙂

Moultons are not faster than 700C road bikes. Thats a nonsence. The faster a wheel rotates the more resistance you have to fight against - windage of the spokes, friction of the bearings. The fact is that for a given gearing a larger wheel will be faster. Forget inertia's and accelaration - we're talking road bikes here not motorbikes, so it is negligable.

Recumbants are faster due to them being more aerodynamic and aerodynamic drag is by far the overriding thing you're fighting against.

Well, yes, and that too. Obviously.

+1 stu1972

Oh, back to the OT - wouldn't there be a fair amount of wasted energy with the Moulton flexing with the long unsupported seat-post?

Moultons are not faster than 700C road bikes. Thats a nonsence. The faster a wheel rotates the more resistance you have to fight against - windage of the spokes, friction of the bearings. The fact is that for a given gearing a larger wheel will be faster. Forget inertia's and accelaration - we're talking road bikes here not motorbikes, so it is negligable.

Nope, sorry.

Wind resistance from the spokes is less with small wheels. The top speed of a spoke is at the top of the wheel, where it's going twice as fast as the bike. Smaller spokes have a smaller cross-section, so lower air resistance.

Bearing friction isn't purely a function of speed, it's also a function of loading and other factors, so wheel size isn't a big issue - and bearing resistance is such a tiny component of drag anyway.

However, with a large wheel the cross-section of the tyre is quite a bit bigger - up to twice as big. Same with the trailing rim. Same with the fork blades.

So, all in all, small wheels on their own even if you keep the rest of the geometry unchanged are quite a bit more aerodynamic.

Moultons were deemed to give an advantage in road racing because the rider could get a better draft from the rider in front therefore giving an advantage over standard wheel bikes.

Oh, back to the OT - wouldn't there be a fair amount of wasted energy with the Moulton flexing with the long unsupported seat-post?

Might be unsupported, but it's pretty beefy. There's also energy being absorbed by the full suspension, but that's more than made up for by the reduction in rolling resistance suspension gives.

Moultons were deemed to give an advantage in road racing because the rider could get a better draft from the rider in front therefore giving an advantage over standard wheel bikes.

That too, but it's far from the only reason.

My "That too, obviously" is in reference to stu1972.

Not wobbliscott, who is, I'm afraid, incorrect- Moltons are commonly known to be faster than traditional road bikes.

Can you substantiate the moultons are faster?

My 36" unicycle hums along like a massive flywheel and feels effortless to keep going but it lacks gears (not gone for a geared hub) off road it is even better over the bumps.

Bikes with 36" wheels exist but they are more for fun, a wheel that big is heavy and not very nimble as it wants to run straight so having a lighter geared wheel is far more efficient than going bigger which has far more drawbacks

Can you substantiate the moultons are faster?

Bicycling Science has quite a bit of detail, as do some other technical books, or the RAAM results are quite interesting as well I think.

Ah, Bicycling Science; a fascinating book, remember reading that years ago.

Interesting that though Moultons may have been 'scientifically' faster they were never taken up by those really interested in going fast.

They were legal for time trials in Britain in the days when their popularity was at its height, but weren't commonly used, and certainly not by the fastest guys. And you couldn't accuse people like Alf Engers of being hidebound by convention 😀

One reason could be that testers at that time were obsessed with weight (with Engers setting the trend for 'drillium') rather than aerodynamics, and I don't recall Moultons as being notably light.

The early developers of MTB didn't need to invent 29 inch wheels as they weren't yet bored of 26 inch wheels

Time trailing and road racing are both dominated by aerodynamics. Add in inertia for road racing as well. Rolling resistance barely figures for fit cyclists. I'll look up a great fact about this in bicycle science about this if anyone cares

I find that amazing that "they" whoever they were couldn't develop or fund the construction a larger carcass building drum and curing mold for a larger bike tyre. Wow

really?

[img] [/img]

[url= http://sonic.net/~ckelly/Seekay/mtbwelcome.htm ]pinched from here[/url]
not sure they were 'investment' type guys. (no offence intended repack 😀 )

not sure they were 'investment' type guys.

Tom Ritchey and Gary Fisher certainly did have the manufacturing capacity by the mid 90s.

Tom Ritchey and Gary Fisher certainly did have the manufacturing capacity by the mid 90s.

GF came out with the first almost-successful 29ers around 2000. They're definatley the first I remember seeing and thinking they were actual serious bikes not some bizzare prototype idea. Bianchi and Klein made 29er XC race bikes as far back as '91, so it's not like it's a new and untried idea.

Personally I think the reason it took so long was suspension forks. All the development through the 90's was on forks, which would have made any development of 29er forks doubly expensive given the small market for them at the time.

Yeah, that's right about Fisher, but that's a full 20 years after Ritchey was advertising his frames and rigid forks in the early 80s. What stopped them putting out 29ers in the mid 80s? Nothing, as far as I can see, other than that they didn't see an overriding benefit to the type of riding being done.

More seriously on the why 29 er now

I think that there is a law that a mountain bike intended for pedalling (a trail bike) can weigh upto 30lbs. This has been quite consistently the weight of my bikes since the 1980s. As the technology improves we get more for the 30lbs. Front suspension, then rear suspension and disc brakes and now we can do bigger wheels as well.

A 1980 FS with disc and 29 ers would have been a heavy horrible monster

the only people who care about wheel size are people who ride 26".

the only people who care about wheel size are people who ride 26".

The whole 29er thing has exploded over the last few years with the big mainstream brands getting involved. The reason for the original post was a thought about all the different sizes that are now offered & yet road wheels haven't been subject to any change. The last major technological advance in road bikes was the bluetooth shifting as far as I know.

That's because the road bike market is very fashion-led - people buy the bikes their heroes ride, and the pro bikes are essentially modern copies of 1930s racing bikes because the UCI stifles innovation.

Which is why letting the UCI anywhere near MTB racing is a bad move.

One or two women have told me that size isn't important, it's what you do with it that counts.

At the time I was confused but now I realise they must have been talking about wheel sizes.

Singlespeed_Shep - Member
the only people who care about wheel size are people who ride 26".

POSTED 27 MINUTES AGO # REPORT-POST

That's so true, 26 er riders are forever moaning about why 29" wheels are from the devil and should be banned.

Get over it.

That's so true, 26 er riders are forever moaning about why 29" wheels are from the devil and should be banned.

Bollocks. What I do object to is being told what is correct when no-one yet has come up with a cogent argument for adopting 29" wheels.

The only place the argument is coming from is the marketing department. They have to justify their existence and unfortunately the vast majority are too thick/gullible to stand up and say "where's the science???".

I'm perfectly willing to accept new technology or ideas as long as someone can give me a good reason to do so.

Bollocks. What I do object to is being told what is correct when no-one yet has come up with a cogent argument for adopting 29" wheels

Rolls better.

But really, don't listen to them. I ride a rigid bike and can happily ignore all the marketing bullshit around suspension.

smaller wheels are lighter, and more aerodynamic, and at tdf speeds that's hugely important

If small is good why are wider rims and tyres more aerodynamic (they offer less rolling resistance too) zipp/HED both state wider is faster and more aerodynamic.

I'm not aware of any research that shows that, and Bicycling Science and other studies disagree. What they might mean is that a few fat spokes are more aerodynamic than lots of thin ones.

I have a copy of that Richards mountain bike book from 1988. An ex girlfriend bought it for me back in 1997. I wasn't impressed as it was so out of date. Now it's pretty interesting

If Moultons are the way forward, why are we all on bigger wheeled bikes? We're all a bunch of idiots!

No. The advantage of big wheels is that they don't fall so far into a hole. On the road (hopefully) there are no holes, so wheel size doesn't matter.

So when everyone goes 29 braking bumps will just get bigger negating some of the usefulness?

As if an extra 3 inches circumference is going to stop your wheel falling into lots of holes.

If Moultons are the way forward, why are we all on bigger wheeled bikes? We're all a bunch of idiots!

Because the UCI doesn't like progress. They prefer pharmacological ways of going faster to technological ones.

If Moultons are the way forward, why are we all on bigger wheeled bikes?

[url= http://www.fudgescyclestore.com/index.php?p=174107 ]Have you seen the price of em[/url]!

MrSmith - Member

If small is good why are wider rims and tyres more aerodynamic (they offer less rolling resistance too) zipp/HED both state wider is faster and more aerodynamic.

dunno what zipp/hed are on about, but if want to make a thing with low drag, start off with a small thing

So when everyone goes 29 braking bumps will just get bigger negating some of the usefulness?

As if an extra 3 inches circumference is going to stop your wheel falling into lots of holes.

Nope just smooth them out, have you not been reading the reviews?

dunno what zipp/hed are on about, but if want to make a thing with low drag, start off with a small thing

If you don't know what they are on about that suggests you do not work in aerodynamics or are qualified to back up your theory that you need to 'start of with a small thing' for low drag? Or maybe you do and know different?
I'm not qualified innaerodynamics but I think I'll take what i have read about HE'D, Zipp and Paul Lew (lew then Reynolds wheels) say as valid. (that wider rims are more aero on a road bike.)

well, i'm convinced.

2 things that affect drag

The drag coefficient and frontal area, usually abbreviated to one function CdA as for an object you can't easily change either, i.e. there's no point quoting Cd for a car, as you can't shrink it.

So halving the wheel size would halve the area (like a moulton).

Wider rims reduce Cd by flattening the tyre sidewalls so it presents a more streamlined shape rather than narrow rims which pinch the tyre in again at the bead, you'd get a similar (well, even better) effect running 21mm tyres, but they're uncomfortable and a harder sell to the fatty sportive set.

The reason it makes chuff all difference on an MTB is we're doing half the speed and drag increases with the square of speed (assuming the reynolds number is high enough, which it will be). So things like rolling resistance of the tyre and it's ability to roll over stuff is more important.

A ride on an old Moulton with the correct tyres will quickly disabuse anyone of the notion that they are slow.

They do need a different technique to a larger wheel bike because of their suspension - that would probably come more naturally to the current full suspension generation than it did to mine. A lot of records were taken on the original Moultons before the UCI made them persona non grata. In fact I believe one record still stands.

They don't give the feedback of "fast" like a 700c wheel, but that is because we are conditioned to recognise road vibration transmitted directly into our joints from 120psi tyres as fast - you don't get that high frequency vibration with the Moulton - but look at average times or a speedo, and they are fast thanks to the suspension. The suspension lets the small wheel ride easily over obstacles just like a larger wheel so there is less resistance.

But taking the 26" wheel argument to its extreme - if a 26" mtb wheel is superior to a 29er, then logically a 20" wheel would be even better. We all know that's ridiculous or the trails would be infested with BMX type bikes. If bigger is better in the case of 20" v 26", then surely the same applies for 26" v 29"?

Edit: the last paragraph of the thisisnotaspoon's post says it best.

I theory the larger the rolling dimater the lower the rolling resistance. However Mr Moulton did rolling reistance tests (on a drum) and found the opposite. So air resistance was not the reason.

The suspension lets the small wheel ride easily over obstacles just like a larger wheel so there is less resistance.

So a 26” fs bike is faster than a 29” rigid with everything else being equal? That's not what 29er riders that I know say.

That's because suspension absorbs energy in it's smoothing action, whereas a larger wheel does not.

However I do wonder how much of this is psychosomatic.

Because the UCI doesn't like progress.

Regardless of the UCI and their many faults, I don't think sport necessarily has to be about technological progress at the expense of all else. Road bikes have moved forward in many ways; materials, gearing, aerodynamics, electronics etc. but ultimately the modern road bike is something that a pre war bike racer would recognise as the same machine. I like that direct connection.

I don't think it would be the same if come July we were treated to fairing covered recumbents hooning up the Champs-Elysees.

mangatank - Member

Tom Ritchey and Gary Fisher certainly did have the manufacturing capacity by the mid 90s.

Yup, but neither has yet developed a working time machine with which to deliver those tyres to the 1970s.

So a 26” fs bike is faster than a 29” rigid with everything else being equal? That's not what 29er riders that I know say.

Well, no, because a 29er FS would be even smoother.

But less aerodynamic.

In my experience of MTB rims before the late 90s, even 26ers were struggling to have the strength required to get rad and I certainly wasn't giving them nearly the abuse I would these days... 29ers would've crumpled and died if you just looked at them from a funny angle.

Besides that, the geometry of 29ers will forever be compromised by clearance around the junction of the chainstays and BB, not to mention toe clearance for the front wheel... (st)roll on.

As for the future of road bikes, say goodbye to the complexities of designing around larger wheels and say hello to a world of fun:

http://minivelo.co.uk/#1

Hipper that a hippy hippos hip:

I_Ache - Member
So a 26” fs bike is faster than a 29” rigid with everything else being equal? That's not what 29er riders that I know say.

I would expect to find that, all else being equal, and I ride a rigid 29er. However a skilled rider on a rigid bike has about 10" of suspension available if he/she stays out of the saddle, so that can make a nonsense of the comparison.

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Wider wheels on a road bike can produce lower overall wind resistance, but they're not more aerodynamic on their own.

More of the spoke is hidden behind the tyre and the wider tyre smooths the flow of air onto the downtube. There could be benefits around the interaction of the air with the forks and calipers too.

Isn't there an aesthetic balance between wheel and frame?

I always struggle to get past a medium on a 26 MTB because anything bigger looks like a gate.

Same for road bikes, rather than getting hung up on sizes shouldn't the wheel just be proportionate to the frame.

May give the factories a headache admittedly.

Perhaps. But most modern road bikes are hideous- take a blob of melted wax, cover it randomly in stickers. So let this wheel size disaster come, it makes but one more.

So really then I should be getting a mountain bike with bigger wheels, and a road bike with smaller wheels when for years ive been told just the opposite (throws cap on floor and stamps on it)

Isn't there an aesthetic balance between wheel and frame?

I always struggle to get past a medium on a 26 MTB because anything bigger looks like a gate.

I agree with this, I've always been between around a 21"ish frame so the biggest benefit to me is that 29" wheels make my bike look normal.