Front mech trim - e...
 

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[Closed] Front mech trim - end of tether.....

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Posts: 6
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Hi

Ive been bodging with my front mech for 12 months and its still not right. Theres one last roll of the dice which Id like to take advice on before one of us does the decent thing with a ritual disembowelling cutlass - which I hope isnt me

OK the facts:

Road set up, Shimano 105 double
Chain rubs on outside (ie away from bike) of cage in 2 highest gears ie the 2 small ones 🙂
Adjustment screws are all fine, and more movement has the chain off
Cage is aligned with chain properly
Its currently as good as its been after winding up the cable tension possibly a bit too tight, as in when I shift down at the front to the smaller ring its a bit sluggish to make the shift

The next step is to move the mech either up or down
Ive tried every other variable leaving this as my last shot

The question is which way first?
Any ideas well received, especially informed ones 🙂

I just cant work out where its rubbing and how it will change by moving it in this plane hence the question
But what I do know is that every step of the bodge pathway usually results in double the pain than leaving well alone!

Cheers!!


 
Posted : 04/06/2013 3:15 pm
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you know it has a micro?? shift to move the mech in/out slightly without actually moving the chain from 1 ring to the other, yeah?


 
Posted : 04/06/2013 3:17 pm
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Nuclear option of single ring + mtb cassette?


 
Posted : 04/06/2013 3:31 pm
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is the angle of the mech right? On my mountain bike I have to angle the mech slightly diagonally to stop it rubbing in big/small. Not much, just a mm or 2

kendo954 - Member

you know it has a micro?? shift to move the mech in/out slightly without actually moving the chain from 1 ring to the other, yeah?

can't do that on the big ring, can you?


 
Posted : 04/06/2013 4:03 pm
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My Campag has 5 trim settings.

That information is of absolutely no use to you though. 😀


 
Posted : 04/06/2013 4:08 pm
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Decided to drop it a couple of mm
Thinking some Belgian lager will help the project

Wish me luck


 
Posted : 04/06/2013 7:21 pm
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Retro - yes on both rings


 
Posted : 05/06/2013 6:09 am
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Is your chain line ok? Could always try a slightly wider bb if not


 
Posted : 05/06/2013 6:20 am
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iamsporticus - Member
Decided to drop it a couple of mm
Thinking some Belgian lager will help the project

good plan going down and some beer - couple of situations would give this a go and this one of them - did it work? must be a million or so 105 doubles that work ok
- incidentally I bought a road bike from a well known UK chain (E) and couldn't get the front mech right - despite it being a Trek that had to be set up by a shop etc etc - worked fine when I put it in correct position still annoyed 5 years later as had to travel to shop to pick up bike especially rather than get delivered


 
Posted : 05/06/2013 6:26 am
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Sounds like a chainline issue putting the chainset too far over, is your chainset + bb the right spec? Or is the outer plate of the cage bent in slightly? I've had a similar issue caused by a mis-shift, plate got a minor bend in it and took a while to notice why the adjustment was out.


 
Posted : 05/06/2013 7:05 am
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Iv had this problem recently with an xt front mech on 9 speed double + bash - bottom line - you need to move it up
If you look closely there is a step change in width - the mech is narrower at the top - on Shimano anyhow


 
Posted : 05/06/2013 7:32 am
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Angle adjustment of front mech can help in this instance.

Assuming you know about the trim function for both rings. Read the shimano instructions and start over from scratch.


 
Posted : 05/06/2013 8:12 am
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Chain rub is normal at the extremes of the cassette, you just need to trim the LH lever a little.


 
Posted : 05/06/2013 8:16 am
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sorry for the suspense 🙂

Despite looking OK-ish I dropped the mech 2mm leaving a "waffer thin" gap between outer ring as per Sheldon's recommended set up

It seems fine on my workstand but I havent had the chance to ride it properly yet
Fingers crossed


 
Posted : 05/06/2013 9:20 pm

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