Hybrid and MTB frames - possibly dumb question

Is there any size difference, in general, between hybrid and MTB frames? I
mean, would it be possible to mount 700 wheels on an MTB frame, or would I
need to use one with a different form factor?

--
Q: How many right-to-lifers does it take to change a light bulb?
A: Two. One to screw it in and one to say that light started when the
screwing began.

"Eugenio Mastroviti" wrote:

Is there any size difference, in general, between hybrid and
MTB frames? I mean, would it be possible to mount 700
wheels on an MTB frame, or would I need to use one with
a different form factor?

In general a frame designed for 700c wheels will differ in its geometry
from one designed for 26" wheels, but the overall diameter of a 26" rim
with a 2" off-road tyre is quite close to that of a 700c rim with a narrow
racing tyre, and the substitution has been done. One of Cannondale's
black-on-black 'Bad Boy' models came with a pair of 26" wheels for off-road
use, and a pair of 700c for the road.

The major hurdle is providing braking. The Cannondale used disk brakes. Few
rim brakes have the necessary reach adjustment to cope with both wheel
diameters. Older forks tended to be about the right length to allow a
caliper brake to be used, but modern suspension-corrected forks would
require an impracticably long reach. I've seen adapters used to move the
effective position of the brake boss the necessary 3cm.

What is it that you're trying to achieve?

James Thomson

On Tue, 06 Jul 2004 22:51:34 +0200, James Thomson wrote:

What is it that you're trying to achieve?

Basically, an ultra-light commuter's bike based on a carbon MTB frame. It
doesn't necessarily make sense, and it's something I won't have the budget
for until at least December, but I was wondering if it's feasible at all.

Eugenio

--
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One who believes that the New Testament is a divinely inspired
book admirably suited to the spiritual needs of his neighbor.

in message , Eugenio
Mastroviti ') wrote:

Is there any size difference, in general, between hybrid and MTB
frames? I mean, would it be possible to mount 700 wheels on an MTB
frame, or would I need to use one with a different form factor?

It's not generally possible to mount 700c wheels on a frame designed for
26inch unless you are using hub or disk brakes because the rims are
slightly different diameter and thus the brake mountings will be in the
wrong place.

However you can get narrow slick tyres for 26inch wheels.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/
;; If God does not write LISP, God writes some code so similar to
;; LISP as to make no difference.

"Eugenio Mastroviti" wrote:

Basically, an ultra-light commuter's bike based on a carbon
MTB frame.

A Pace RC31 carbon fork might be an idea for the front end. They come with
a disk-mount, and optional clamp-on V-brake bosses that can be clamped
anywhere on the fork blade. Either way, that would take care of braking at
the front. A fixed gear at the back (with a White ENO hub if your frame has
vertical dropouts) would be ultra-light, and would deal with the rear brake
issue.

I'm inclined to think that 26" wheels would make more sense though. A side
effect of running narrow 26" slicks on a mountain bike is that the bottom
bracket height and steering trail are reduced, which tends to make sense
for road use. 700c wheels would have the opposite efect.

James Thomson

Eugenio Mastroviti wrote:

Basically, an ultra-light commuter's bike based on a carbon MTB frame. It
doesn't necessarily make sense, and it's something I won't have the budget
for until at least December, but I was wondering if it's feasible at all.

I'd stick with 26": you can get performance wheels built up in 26" and
pop something like Schwalbe Stelvios on and you'll have plenty of speed
potential. It's an old myth that you need 20mm 700c wheels to go fast.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

On Wed, 07 Jul 2004 09:32:33 +0100, Peter Clinch wrote:

I'd stick with 26": you can get performance wheels built up in 26" and
pop something like Schwalbe Stelvios on and you'll have plenty of speed
potential. It's an old myth that you need 20mm 700c wheels to go fast.

Thanks everybody for the advice - this makes things a lot easier.

Since you guys are in such a helpful mood, do you know of any ways to
explain to my better half that this kind of purchase could be construed,
in some ways, as more important for my life and well-being than changing
the curtains in the living room, the kitchen table and the garden lights
for the THIRD time this year?

Well, short of getting down on my knees and begging for mercy, I mean.

Eugenio

Eugenio Mastroviti wrote:

Since you guys are in such a helpful mood, do you know of any ways to
explain to my better half that this kind of purchase could be construed,
in some ways, as more important for my life and well-being than changing
the curtains in the living room, the kitchen table and the garden lights
for the THIRD time this year?

I'd personally go for "it is a bicycle, QED"

But there again my better half has just spent a small fortune on a very
nice bike herself, so Understands These Things... YMMV! ;-)

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

in message , Eugenio
Mastroviti ') wrote:

On Wed, 07 Jul 2004 09:32:33 +0100, Peter Clinch wrote:

I'd stick with 26": you can get performance wheels built up in 26"
and pop something like Schwalbe Stelvios on and you'll have plenty of
speed
potential. It's an old myth that you need 20mm 700c wheels to go
fast.

Thanks everybody for the advice - this makes things a lot easier.

Since you guys are in such a helpful mood, do you know of any ways to
explain to my better half that this kind of purchase could be
construed, in some ways, as more important for my life and well-being
than changing the curtains in the living room, the kitchen table and
the garden lights for the THIRD time this year?

What do you currently spend in a year - total - on commuting?

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

;; When your hammer is C++, everything begins to look like a thumb.

On Wed, 07 Jul 2004 11:05:01 +0000, Simon Brooke wrote:

Since you guys are in such a helpful mood, do you know of any ways to
explain to my better half that this kind of purchase could be
construed, in some ways, as more important for my life and well-being
than changing the curtains in the living room, the kitchen table and
the garden lights for the THIRD time this year?

What do you currently spend in a year - total - on commuting?

Ay, there's the rub. Next to nothing - I already have a mountain bike,
which I'd like to use only for MTB stuff at weekends. So the issue is, I'd
like a SECOND bike, optimised for urban commuting... ehm...

Sigh, I can see where this is going. Off to Ikea...