700c vs. 26 in. wheels--any real diff in speed?
 

Hi Commuters--

I am a sometimes bike commuter and an always bike errand runner.
Basically I drive a lot to work but make sure almost all other trips
(groceries, errands, etc) are by bike. I am working towards
commuting more. I am seriously looking at a mtn bike
with 26" wheels. I rode an old mtb for years but have
been riding road bikes since. I find them zippier but I think
this is mostly in my head. I want a fast bike bc. the distances
are kind of large (the ones I cover).

Thoughts or experiences on this issue/question?

Best,
KV

29" = 622etrto = 700c

Get the best of both worlds - if you get a 29er mtb and a 700c cyclocross bike with disc brakes then, dependent on tyre width, your wheels will be interchangeable.

Apart from that my experience of slicks on a 26" bike compared to a 700c road bike - the 26" mtb was quicker to accelerate but slightly harder work to keep at a high speed.

Depends on width, tread design, and weight. Speed will be the same for 700c and 26" wheels if the tires are the same width, tread design, and weight. Even 20" tires will roll the same as 28" wheels as long as the tires are about the same width and tread design.

On the road, long distances, possibly continuous headwinds I vote roadbike. Mine is a cyclocross frame with Midge Bar One drop bars. I think frame choice is more a consideration. I used to ride a mtb full suspension. I first got rid of the suspension fork, replaced it with my cyclocross fork. I was committed to a frame in the near future.

When I finally got it all and put it together, I was more than a little surprised at how much easier it was to cover my 22 mile roundtrip commute. I am riding as a singlespeed 48x11 that didn't exist on the mtb and faster now than ever. The tires and innertubes for my road/cyclocross bike are much lighter than the mtb counterparts.

Ergonomics of the current bike win handsdown for commuting over the road. I ride the entire trip in the drops or on the hoods. Headwinds don't affect me nearly as much as they did on the mtb.

The longer the distance, the more a roadbike becomes attractive.

I use all three......
The 700's will be easier to maintain speed on
but 20"s accelerate best of all, lots of pedaling to keep up
speed. 26's fall in the middle somewhere.........:)

With similarly equipped tires I have found no difference in 700c and 26" wheels, at least not anything I could notice.

the gearings for 20" don't force you to pedal real fast or hard. My folder has a 52T chainring and 11-34 rear cassette which is a nice range of gears to use.

I still prefer my 700c bikes though. Especially because of the range of tyres you can use and the ease of getting them.

I think the short answer is 'no'

On rough roads, the smoother ride of the larger diameter wheels is an end in itself, and I do think it improves speeds a bit as well.

It's also tougher to get lightweight road tires in 26".

Correct. On-road, anything between 16" and 29" is about the same for speed if you keep overall bike weight and tire style about the same. Aerodynamics, weight (of rider+bike+cargo combined), and tire style are much more important considerations than rim diameter.

For the riding that 90 percent of the people do 90 percent of the time, I can't fathom that tire size would make a lick of difference. Width and tread, on the other hand, can make a significant difference.

+++1 -- would just add 'EFFECTIVE gearing about the same' to the list (i.e. a 90 inch [or whatever] gear is a 90 inch gear/doesn't matter how you get there).
One further comment re. a post above: yes, all else being equal a larger diameter wheel rolls more easily over rough surfaces than a smaller diameter one, but (there's always a 'but') a wider tire does so as well as against a narrower one: e.g. given = tread design/quality etc., a 26x1.5, say, against a 700c x 32, rolling resistance will be a saw-off. The larger wheel will cope better with larger, sharp-edged irregularities, the wider tire with the constant flow of surface irregularities. Take your pick, based on your riding conditions.

I agree, all else being equal.

But tires and wheels aren't the whole story. In general (there are always exceptions, and I'm sure someone will be along to point them out), the mountain bikes are often beefier and heavier, and the geometry is different to achieve a more upright ride instead of the more efficient riding position that you find on a road bike. These factors also contribute to why your road bike feels "zippier". I regularly ride both my road bike and a hybrid that I use more for commuting and errands. Even though both have 700c wheels with comparable size tires, I average about 2 mph faster on the road bike because of the different configurations.

Asked a similar question a few months ago . . .

http://www.bikeforums.net/showthread...632&highlight=

Couldn't agree more -- in fact, I'd go so far as to say that these kinds of things are where any real differences in speed come from, as between bikes, rather than '26" or 700c' wheels. Geometry and ride position (affects both aerodynamics and pedalling efficiency), even chainstay length, overall weight (to a point), all of these things have marked effects.

What would the difference be? Other than rotational inertia, the only difference I can imagine is that the 700C wheels will put fewer RPM on the bearings, and thus possibly less total friction. But that would only be noticeable for really crappy wheels.

The larger questoin is what you want the bike to do. Are mountain bikes 'zippier'? Perhaps because of the smaller frames they feel more nimble, and they probably can accelerate pretty well. I wouldn't want to ride long distances on a mountain bike, though. Maybe an old-school touring bike would suit you well?

What about a touring bike? (particularly a sport tourer) Definitely designed to carry stuff, and you still get many of the features of the road bike.

I think the only advantage of a mountain bike is cheapness. If you aren't going to use it at all for off-roading then I would find a rigid one (ie no suspension) and change the tires to something slick, narrower, and higher pressure. Basically a DIY hybrid. In terms of a hybrid that already exists, what about something like the Kona Dew? Retails for $400, has 700c wheels but straight bars. Seems like a decent enough commuter.

I commute on a 48x19 fixed gear rush hour with 700x23c wheels and 26" mountain bike with 1.2" slicks. I always feel like the fixed gear bike is by far the faster of the two even with the relatively low gearing. The fg feels faster when i get up to speed on open bike paths. The fg is a lot easier to maintain speed. When i get the mountain bike up to speed, even in the highest gear (42x11), i feel like i really have to work to keep it there. The only time the mountain bike feels faster is when i get to bomb down the bridges in nyc...the funnest part of my commute.

However, i never attributed this difference to geometry, weight, and aerodynamics. I would like to put 650x23c wheels on my fixed gear bike to see the difference in speed at different velocities.

The funny thing is, a lot of this seems to be a revival of the types of bikes that were popular 15 or more years ago - relaxed geometry, flat or touring bar, bigger 700C tires, angled downtube and a raked fork, and often a steel frame. And if that is indeed what one wanted, there's an abundance of such bikes easily had for under $100. I'm commuting on one now.

I would disagree with this. Older steel frame mountain bikes make great tourers. They have long chainstays, relaxed geometry, strong frames and the 26" wheel is inherently stronger than a 700c or a 27" wheel. They usually have room for fenders and racks.

Fair comment, but -- again -- don't see where/how these felt differences could come from wheel diameter per se. The only way to even begin to know would be to run multiple timed/heart rate monitored tests over a fixed loop multiple times, with:

1. Equalized gearing at a set cadence
2. Tire quality/tread (if any) design equivalent; ditto wheel quality
3. Same kind of riding position set up on two bikes (or switch wheelsets on one bike), re. rider's aerodynamic and pedalling efficiency
4. Rigid or suspension fork on both

and see what happens. Whenever this has been done, formally or informally, the usual result seems to be that wheel diameter per se has very little, if any, real effect. Many, many other factors do, but that's not one of them. The 'Porsche effect' is real, of course (60 mph feels way faster in a Porsche than in a BMW 7series), but that's a different thing.

What I've seen in most bikes that come with 26" tires is that they have higher bottom brackets than sport road & touring bikes so if you want to sit as low on a 26" bike w/ a higher bottom bracket as you would on a sport/touring bikes while maintaining the same geometry between your seat & bottom bracket, you'll have to have the handlebars farther below the saddle on the 26" bike than the 700c bike. That's not OK for me as I want my seat about level w/ my handlebars.