Installing road wheels on MtB with direct-pull cantilever conversion brackets

Appreciating the pedaling efficiency of Rigida 27x1" clincher rims and tires I fabricated some adapter brackets to mount on my low-end
mountain bike frame originally set up with direct-pull cantilever brakes. Conversion is made by removing the 26" mountain bike wheels and brakes from their mounting posts. By installing the horseshoe style adapters on the existing mounting posts the brakes can be remounted on secondary posts located higher up the adapters. Simply install 27" road wheels with HP tire sizes up to 1 1/8" having similar index shifting gearing geometry and readjust the brakes. Naturally, 700C rims with similar tires will have even more clearance from the frame. CONS are 1) having excessive brake cable housing from the "raised" brake post height and 2) increased bike leaning when utilizing the welded-on kick-stand with the larger diameter road wheels. I would attach photos if I knew how. This setup works great for my riding needs where one bike is desired for efficiently riding around town for most of the year while still accommodating mountain bike wheels for one week of mountain bike camp each summer. I'm wondering if there is a market/need for this kind of bracket?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 23 Jan 2012 11:34:20 -0800 (PST), Gordon Babbitt

To answer your question, I doubt that there is much market for an adapter to use both 700C wheels and the normal 26" wheels on a MTB for two reasons:
1. You can get 1.3" wide, high pressure, 26" tires that roll about as well as the larger 700C 1-1/8" tires.
2. Generally bicycle people are divided into two groups - those who just ride and leave any tinkering to their local bike shop; and those who wouldn't think of letting the LBS near their darling. The first group wouldn't understand the difference between 700C and 26" tires and the second group probably would prefer to just buy another bike.
As for actual difference, I have an aluminum frame road bike with 700C tires and a steel frame touring bike with 26 x 1.3" tires. The tourer is heavier then the road bike, but even with that handicap it is still only about 1 KPH slower over 100K; or 100 Miles for that matter.
-- John B.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 1/23/2012 8:32 PM, John B. wrote:

Most wheel changes I have heard of is people with older 27x1-1/4" bikes that they wanted to fit 700c wheels on.

I think Continental makes a 26"/559 tire that is 1-1/8" wide. At least, they did. A few years back I looked around once for the narrowest tire that would fit on a 559 rim, and that was it.
Most people who want to run different sizes of wheels on one bike just get a frame that has disk brake bosses and that cures any brake-fit issue. Fitting narrow tires to a MTB still introduces gearing problems, however.
The gearing on a MTB is already higher compared to a road bicycle: the biggest chainring on a cheaper road bike is probably a 52-tooth, and the biggest chainring on a MTB is usually 48-tooth (if it is even that big). And since bicycle tires are bias-ply only, they have a round cross-section--so a narrower tire is also going to have a smaller outer diameter, too.
So the MTB is already geared wrong for road riding--and then if you go putting a skinny tire on it, the rear wheel gets smaller,,,,, and the effective gearing gets even worse.
You can get some fat smooth-tread tires in MTB sizes that would perhaps do better for longer riding, even though they feel heavier while accelerating and climbing hills. The Maxxis Hookworms are listed as being 2.5" wide, and the Schwalbe Big Apple tires come in a 2.3" width.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I looked in the 2010 catalog and the narrowest I could locate was a 26 x 1.3". there was a 20" x 1-1/8th though.

That is not always true. I use mountain bike gearing on my touring bike 44-32-22 with either a 11-34 or 12-32 cassette. works a treat if you are in hilly country.
Another problem that the O.P. didn't mention is that the rear hub/axle has a different spacing if changing between MTB and road wheels. It is not insurmountable but does require a bit of tinkering.

-- John B.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.