# Possibility of 700c wheels when 27 inch wheels are stock



## RalThunder (Jan 22, 2007)

Hello, I've been riding/commuting using my 70s Raleigh with a converted single speed rear wheel. I want to move to a rear wheel with a flip-flop hub. The question is do I go in for a new wheel set of 700c wheels or do I stick with the 27 inch wheels with a new rear wheel? I only have the front brake and that is an easy adjustment for the larger wheels. the frame should accommodate the larger wheels but I'm wondering if this will change the handling of the bike adversely. Thanks!

Dustin


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## ukiahb (Jan 26, 2003)

700c wheels are actually smaller than 27" wheels by 8mm in diameter, so the brake pads need to drop about 4mm and most old calipers have enough adjustment range to do that. I've done the swap on geared and fixed bikes, the only downside was that pedal strikes are slightly more likely, though you could get the 4mm of ride height back by running taller tires.


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## Richard (Feb 17, 2006)

ukiahb said:


> 700c wheels are actually smaller than 27" wheels by 8mm in diameter, so the brake pads need to drop about 4mm and most old calipers have enough adjustment range to do that. I've done the swap on geared and fixed bikes, the only downside was that pedal strikes are slightly more likely, though you could get the 4mm of ride height back by running taller tires.


I went with 700c's on my '70's Raleigh conversion simply because of the availablity of tires.

I used an NOS rear DiaCompe center pull we had laying around the shop as it has more reach than a front (compare 'em - the arms are longer.) There is also the new Tektro with I believe up to 70mm of reach.

As to pedal strikes, I'm running 700x28's and still have had a few. I attribute it more to the "touring bike" geometry of the old Supercourse and the low bottom bracket.


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## JCavilia (Sep 12, 2005)

*brake reach*

is the only serious issue. See if there's enough slot to lower the pads 4mm from where they are now. Sometimes you can get away with filing the slot a little longer (older components tend to have enough extra material). If not, you'd need to do some kind of a drop bolt, or get a new, longer reach brake. There are decent inexpensive ones widely available (those Tektros somebody mentioned work fine).

A lot of people have done this conversion. My fixie is a 70's vintage Rampar frame. The switch to 700c wheel was no problem. The 4mm difference in height will almost certainly be unnoticeable in terms of handling or pedal clearance. 

As I'm sure you're aware, you have a much bigger selection of rims and tires available if you switch to 700c.


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## RalThunder (Jan 22, 2007)

*27inch wheels*

I have noticed the lack of tire selection for the 27 inch wheels. Are 27 inch wheels used anymore? I mean, would a bigger wheel be better or give some sort of an advantage? I guess I'm not racing this bike and if I were it would be some sort of light cycle ocross and I doubt I'd be able to get cycle cross tires in 27 inches.

Dustin


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## JCavilia (Sep 12, 2005)

*Basically obslete*



RalThunder said:


> I have noticed the lack of tire selection for the 27 inch wheels. Are 27 inch wheels used anymore? I mean, would a bigger wheel be better or give some sort of an advantage? I guess I'm not racing this bike and if I were it would be some sort of light cycle ocross and I doubt I'd be able to get cycle cross tires in 27 inches.
> 
> Dustin


27" wheels really aren't used anymore on new bikes. There are still lots of old bikes around, so several manufacturers make tires, and a few make rims. Much more selection in 700C. 

When you ask about "bigger" wheels, keep in mind the difference is very slight. 8mm difference in diameter (i.e., a little more than the thickness of a pencil). You can't feel the difference, and it's hard to see it. They weren't made that way for any particular advantage -- it was just a different standard, a historical accident. BTW, there are a hell of a lot of different bike tire sizes, historically, and many are confusingly labeled. Sheldon's article is pretty interesting. http://www.sheldonbrown.com/tire-sizing.html


There are a few cross tires made in 27". I have some I use on my winter commuter when the slop is on the roads. But there are few choices.

Bottom line: If you're going to build new wheels (because you want a new hub), you're probably better off going to 700C, unless your old rims are in very good shape or you're very attached to them and want to re-use them.

Edit: One more point. If it's only the rear wheel you need to change (for the flip-flop hub), and you're economizing, there's no real reason you couldn't use a 700C on the back and a 27" on the front. You wouldn't be able to rotate the tires, and you may not even be able to find matching tires, but that's not really a functional problem. You wouldn't have to worry about brake reach then. It would be unorthodox, but it would work. I really don't think you'd notice the difference in wheel size.

On the other hand, if your old rims are still good, the cheapest solution may be to build a new rear wheel with the old rim. cost is hub, spokes, and labor (if you can't build it yourself). This is a highly theoretical point I'm making. If those are original rims from the 70's, they're probably pretty trashed, unless they spent most of their life hung up in somebody's garage.


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## RalThunder (Jan 22, 2007)

Thanks JC. That is a good point about just getting the rear wheel built and using the old 27 inch wheel for the front. That'd probably be just fine. I bet I could find someone who wants to get rid of an old 700c front wheel. Great idea! Good article on Sheldon's website. Man he's got the best stuff there!

Dustin


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## ukiahb (Jan 26, 2003)

27" in front and 700c in back does indeed work in practice, the difference is noticeable visually and looks a little funny, but the ride is fine, set this fixed conversion up that way....


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## Sixty Fiver (Jul 7, 2007)

I like my old 27's and managed to find some old stock 27 by 1 tyres (Panaracer Tri Sports) here and know that Harris Cyclery carries a good number of 27 inch tires including some 700:22 (27 by 7/8) Avocet racing tyres.


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