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chain rubbing on front mech

 
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undapressure
I am sure there is an easy fix for this (aside from taking it to the LBS). My chain is rubbing on the sides of the front mech whenever it is in the top or bottom 2 sprockets on the back cassette. How can I stop this?

Also, my rear mech used to change easily with the shifters, now you have to give it a harder push to change it but the gears are indexed fine and shifting well when they do. Any ideas what this could be?

Thanks

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nicklouseLives Here
sounds like service time.

yes the chain will rub in some gears combos, you dont say which.

stiff changes is a sign of dirty/rusty/ unlubed cables.

"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools Question SheldonBrown
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undapressure
Its only running the granny ring and a 36t middle on the front with a bash guard. Only use the middle ring though and its this one where it is rubbing on the front mech when in the top and bottom 2 gears on the back

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nicklouseLives Here
undapressure wrote:
Its only running the granny ring and a 36t middle on the front with a bash guard. Only use the middle ring though and its this one where it is rubbing on the front mech when in the top and bottom 2 gears on the back

so which does in rub in when in the granny?

and which does it rub in when in the 36T big ring?

sorry that is a s clear as mub.

"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools Question SheldonBrown
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undapressure
Sorry. Although I have the granny ring on, I never use it. When it is on the 36t big ring on the front, it rubs on the top 3 (largest) on the back and bottom 2 (lowest).

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ChrisMidsUK
Save me starting a new topic on the same subject, I'll ask advice here.

Not long ago I had problems with the gear shifters (sram x7) on my stumpy fsr comp 09, I'd been told by some riders back in early may that it's a common problem with these shifters 'sticking' and everything they had said about that turned out to be right.

This problem has gone on for many months, don't ask me why but one day I started twisting the things near the shifter itself (I think they could be barrel adjusters or something like that?)
This actually worked at first but the sticking shifter problem soon returned and I ended up in a mess after twisting too much, now the gears were not dropping in right, chain was now rubbing on the Shimano M660 SLX front derailluer.

After consulting the park tools site http://www.parktool.com/repair/readhowto.asp?id=75
I tried to make adjustments myself but I'm never going to win any 'newcomer mechanic of the year' awards so I had no choice than to sling in down the LBS.

I decided to buy some sram x9 shifters, got them for £60 for the pair so was quite chuffed, the aim was to kill 2 birds with 1 stone, get the problems sorted and get those troublesome shifters off.

I was pleased with the new shifters but the chain was rubbing right from leaving the store, I should have gone back straight away but thought perhaps it needs time to settle down, similar to the fact the brakes need to 'bed in'.
I am aware that there are certain combinations of gears to be avoided that cause 'extreme crossover' situations but I always thought (perhaps wrongly) that the middle ring up front is the one ring that this shouldn't happen on, the bike store replied to an email I sent informing me that this 'can happen' but this was the middle ring up front and the largest 4 cogs on the rear casette causing me the grief.

I thought this a little strange as the 2 outer ring up front had no chain rub problems whatsover (aside from extreme crossovers)
I examined the bike further and noticed the Derailleur Height was not how it should be, according to park tools on the link above that states,

''The gap between the teeth of the outer chainring and lower edge of the outer cage plate should be 1-2mm, about the thickness of a penny.''

The gap is now actually 5mm and I'm sure it wasn't like that before, I email the LBS back to explain this but have heard nothing back after a week.

I'm very dissapointed because it looks like this 5mm height is what's causing the problem, when the chain is on the middle ring up front and any of the largest cogs to the rear, the chain is rubbing on a part inside the front derailleur that is curved.

Can someone please let me know if they think the derailleur need lowering? I dare not do it myself but I may have to find another bike store as I'm unhappy with paying for a full service, on top of the fee to have shifters put on, only to get my bike back in not so tip top condition.

Sorry for the long post, just wanted to give some background on how I got from A to B. Cheers.

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nicklouseLives Here
undapressure wrote:
Sorry. Although I have the granny ring on, I never use it. When it is on the 36t big ring on the front, it rubs on the top 3 (largest) on the back and bottom 2 (lowest).


yep it happens set it not to rub on the small cogs. and it will rub on the big cogs.

"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools Question SheldonBrown
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undapressure
nicklouse wrote:
undapressure wrote:
Sorry. Although I have the granny ring on, I never use it. When it is on the 36t big ring on the front, it rubs on the top 3 (largest) on the back and bottom 2 (lowest).


yep it happens set it not to rub on the small cogs. and it will rub on the big cogs.


Is there any way around it or do I just put up with the grinding noise?

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richg1979
just have to put up with it im afrid unlees you ditch your granny ring if you dont use it and remove front mech.

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