Front mech problem

andyforse said:

Fitting a new front mech yesterday (Deore) and I left the recommended 2mm gap between the outer
cage and the big ring. Trouble is when trying to move the chain to the big ring the inner cage
catches on the teeth of the middle ring. So I had to lift the mech about another 4mm so it could
clear it.

It seems to work OK but I wondered if anyone else has had this problem or what might cause it.

Shimano front mechs intended for triple chainset use are generally optimized for a 10 tooth
difference betwixt the large and middle chainring. If you're going for a much smaller jump, as with
a (yuck!) half-step-plus granny setup, you'll get better results with a "double" type front mech.

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andyforse said:

Fitting a new front mech yesterday (Deore) and I left the recommended 2mm gap between the outer
cage and the big ring. Trouble is when trying to move the chain to the big ring the inner cage
catches on the teeth of the middle ring. So I had to lift the mech about another 4mm so it could
clear it.

It seems to work OK but I wondered if anyone else has had this problem or what might cause it.

Andy

I think the newer Deore FD is designed to work with a difference of 12T between the big ring and the
middle ring (ex. 44-32-22). Older cranksets often have 42-32-22 or 44-34-24. I had the same problem
after I replaced the FD. In my case, lifting the FD another 4mm didn't work very well. I had to
replace the big ring.

The chainrings are 22-32-42. Getting a 44 big ring just might be the answer. I think I'll wait till
it wears out or stops working first though.

Thank you both for the advise.

Andy

Quoted message said:

Shimano front mechs intended for triple>chainset use are generally opti ized for a 10 tooth
difference betwixt the large and middle chainring. If you're going for a much smaller jump, as with
a (yuck!) half-step-plus granny setup, you'll get better results with a "double" type front mech.

Quoted message said:

Sheldon "Decimalization" Brown

"Yuck"? And here I thought you were my friend :-3(

May you have the wind at your back. And a really low gear for the hills! Chris

Chris'Z Corner "The Website for the Common Bicyclist": geocities.comczcornerOpen ↗

andyforse <[email hidden]> wrote in message
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Quoted message said:

The chainrings are 22-32-42. Getting a 44 big ring just might be the answer. I think I'll wait
till it wears out or stops working first though.

Thank you both for the advise.

Andy

I'm running Deore front with 22-32-42. Lifted the cage to clear, angled it 'just so', and have zero
problems shifting, well, that aren't related to the (now) badly worn pivots on the mech (have to
overshift a little, but it worked fine for most of the year it lasted un-worn....).

Shaun aRe - Deore mech shortly to be replaced by an XT _conventional_ swing type which will
hopefully wear better than the awful top swing types........).

Those pivots do wear pretty quick don't they.

I'll get the XT myself next time, but I'm not sure if the conventional swing will work with the
Marin Rift Zone I'm riding. Whats the difference between the two?

Andy

Quoted message said:

I'm running Deore front with 22-32-42. Lifted the cage to clear,

angled it

Quoted message said:

'just so', and have zero problems shifting, well, that aren't

related to the

Quoted message said:

(now) badly worn pivots on the mech (have to overshift a little, but

it

Quoted message said:

worked fine for most of the year it lasted un-worn....).

Shaun aRe - Deore mech shortly to be replaced by an XT

_conventional_ swing

Quoted message said:

type which will hopefully wear better than the awful top swing types........).

andyforse <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Those pivots do wear pretty quick don't they.

Yup! 12 months average so far ;-(

Quoted message said:

I'll get the XT myself next time, but I'm not sure if the conventional swing will work with the
Marin Rift Zone I'm riding. Whats the difference between the two?

'AFAICR', the non-conventional ones were designed to bring the clamp band lower on the seat tube
to allow their use on certain full suss designs where a higher band wouldn't have a place to fit
(clamp band is below the mech cage on these). The conventional ones have the clamp band higher
than the cage.

The 'conventional' low end Shimano (Altus? - dunno!) front mech I am currently using just to keep
the chain in place on the single front ring on my FrankenBeater (commute bike) was still working
(although not fantastically) after about 8 years of constant use and abuse. The one that replaced it
(Deore top-swing) lasted less than 1 year before the pivots were so worn it wouldn't shift unless I
had all week to wait..........

Opinions I have solicited as to the comparative longevity of the two _types_ (not 'levels'😉 seem to
back up my experience(s). This is OK for me, as I have enough room on my (HT) seat tube to mount the
cage under the top tube, if I so desired. You probably aren't so lucky, if your bike is an FS Marin,
but I can't picture the bike's design clearly enough.

Shaun aRe