700c rims on frame designed for 26" . . . Possible? Practical?
 

While looking at upgrading rims for my hybrid MTB, the question came up as to if it is possible and/or practical to put 700c rims on a 26" MTB frame. I have lots of wheel clearance but the main questions are hub width and brake alignment.

Has anyone done it? Is it worth the trouble? Does it make a better road/touring bike?

There was a Cannondale a couple years back that had interchangeable 26" and 700C wheels. 26" wheels and fat tires come out about the same outside diameter as 700C wheels and narrow tires. The Cannondale had disk brakes, though.

I think it's do-able, but brake fitment is the real bugaboo. Without seeing your existing bike, I can't say how easy it would be to adapt different brakes.

If you're after a good road/touring bike, I think putting narrower, slick tires on your 26" wheels will get you 95% of the way there at far less cost and complication.

Depending of the fork and chainstay clearance it's possible and can work out very nicely. The only trick is getting the brakes to reach. But you're in luck, the folks at Mavic make an adapter expressly for this purpose.

I've seen folks do this conversion using the Mavic adapter, and it works out great.

Only disc brakes ..OD of tire would need to be the same..

I've thought about doing it on older MTBs with drilled steerer and seatstay bridges but haven't gone to the trouble of sourcing the brakes I'd need for it. Seems like fairly standard reach road calipers would work on the fork of my Mongoose. They'd have to be nutted and the bolt would have to be long enough to accommodate the 1 1/8" steerer.

That's about as much thought as I've put into it.

Oh, I do have a 700c rear wheel on my cheep-o Black Baron bike, but I haven't fit a brake to it.

http://farm4.static.flickr.com/3488/...631047d8_b.jpg
Black Baron Day 8 by Lester Of Puppets, on Flickr

This is all correct, and in addition, if you use hub brakes (disc brakes, for instance), you won't have the reach problem, at all.

In theory, there is no geometry difference going from a really fat 26"-tire wheel to a skinny 700C-tire wheel. Ride quality, of course, will differ greatly.

Good point. And I'd like to add if you're running really slim tires on a 26", like some 1.5" or smaller then you might want to go to 700c to get a little extra bottom bracket clearance. This would allow more pedalling into and out of turns without pedal strike.

My fixed gear conversion started life as a 26" Raleigh Technium mountain bike.

I built new 700c wheels for it which fit quite nicely. A standard reach 105 caliper turned out to be the perfect reach from the reflector hole in the fork crown to the rim's brakeing surface. I never installed a rear brake but that looks to be about the same distance too.

back in the late '80s early '90s some people used to do it to make cheap, but heavyish, cyclocross bikes. they mostly use midlevel sidepull type brakes to get the reach they needed.

Why? You could enlarge the hole in the rear face of the fork crown with a 5/16" drill and use a long recessed nut. They are available as long as 30 mm which should reach through about anything.

I changed a 559 ETRTO wheeled bike to a 584 ETRTO (650B). It is a tourer with canti/linear brake posts. I had to change the brakesets to ones that had more adjustability, and am now using Paul Components Moto-BMX linear brakes because of their extreme adjustability. For me, on that particular bicycle, it was an improvement, overall.

If you do this, remember that the frame-related riding characteristics may change with wheel size (unless you are going from big baloon low pressure to narrow racing tires.) Your bottom bracket height will be higher as will your axle heights, which increases your front end trail by a small amount, and the center of gravity will also be higher. On tourers that are made for 700c wheels, the angle of the rear triangle at the dropout will usually be greater than on a 26 in wheeled design to keep the bottom bracket at the same height.

That nice mountain bike just asked to be converted :) I like it!

Someone (Mavic, maybe?) makes a 26" to 7ooc canti boss converter.

Top

See above: http://www.mavic.com/en/product/whee...Brake-Adjuster

So glad I found this thread when I googled, "Raleigh Technium 700c brake." My situation exactly. Gonna buy a 105 brake now based on Retro Grouch's suggestion. Can't find the Mavic converter right now as their site is undergoing renovation.

You don't need the Mavic site for that, you can get it from several independent dealers.

How cool is that? Hope it works out for you.

Took me forever, but here's the before and after Raleigh Technium 26" mountain bike to 700c single-speed.

Being an Opinion request, I'd say No.

A 700C touring bike frame made as such, makes a better Touring bike
with a 700C wheelset.

but, in MN, its a long winter, the Bodge will be entertaining at least.