Is my groupset not compatible?

Sounds like someone put in a short bottom bracket or changed the cranks
to ones that needed a wider BB. Can you put up some photos of the
problem? That's always helpful.

Andy M-S said:

Sounds like someone put in a short bottom bracket or changed the

cranks

Quoted message said:

to ones that needed a wider BB. Can you put up some photos of the
problem? That's always helpful.

Uh, that's one possible cause, I suppose, but I think its a lot more
likely that the front derailleur's high limit screw just needs to be
screwed down a bit.

Check out parktool.com, they've got a nice illustrated guide to
adjusting your front derailleur.

(Azz) said:

Hi, I'm fairly new to bike repair.
When the chain in on the outer flywheel,

by "flywheel" to you mean "chainwheel"? it helps to use a common
language.

Quoted message said:

the pedal will collide violently with the front mech. Despite
numerous adjustments, I am not able to use the outer flywheel at
all. This was the condition I got when i bought the bike (not new),
and there's no way for me to return it.

muddy fox bikes go back a long way in the U.K. - early 1980's if I
remember correctly from "Cycling Plus" magazine. There is a problem
today with using modern front derailleurs on older cranksets. When
front indexing was invented the makers found that the front derailleur
cage needed to be wider and "3-dimensional" - meaning that the outer
part of the derailleur near the crankset was not flat.

The wider cage reduces the need to trim the derailleur, but makes it
necessary to push the derailleur farther outwards when shifting in
order to engage the inner side of the cage and shift the chain.

The 3-dimensional cage (on the derailleurs I'm familiar with) was
typically an "outer lip" which pushed on a very small part of the
chain causing faster shifts. However, it was common that this "lip"
would score the backside of some older crank arms.

If this is the problem you are having, then you either need a retro
front derailleur (most campy derailleurs, simplex, huret, non indexed
suntour), or you need a more modern crankset. On a modern crankset
the crank arm is farther from the chainwheel.

There is a small possibility that your front derailleur is simply
mis-aligned and not parallel to the crank arm. If that's the problem
you need to loosen the band on the downtube and rotate it until the
outer cage is parallel to your crank arm. This should be checked.

Good luck,

- Don Gillies
San Diego, CA

(Azz) said:

Hi, I'm fairly new to bike repair. When the chain in on the outer
flywheel, the pedal will collide violently with the front
mech. Despite numerous adjustments, I am not able to use the outer
flywheel at all. This was the condition I got when i bought the bike
(not new), and there's no way for me to return it.

What have I got to do to get this Muddy Fox going? Can somebody
please tell me how or any links would be appreciated.

I commend your wisdom in trying to learn to do this yourself.

Terminology lesson: it's not a flywheel, it's a chainring. There are
probably three of them, called the "big ring," the "middle ring," and
the "granny."

Let me introduce you to the basic encyleopedic resource of the
Internet: www.sheldonbrown.com

You don't say what adjustments you've made already. The first thing I
would look at is whether the front derailleur travel limit screw is
correctly set. See the link below for how to do this.

http://www.sheldonbrown.com/derailer-adjustment.html

Hope this helps! Also, a good book on bike maintenance and repair, if
you don't have one, will shorten your learning curve.