help needed with gears problem

DLB

Hi

can anybody help with a problem with my gears - basically i can't use the gear which is the middle chainring (of a triple) and the largest sprocket . Whenever i do the chain jumps onto the smallest chainring and rubs against the front mech. This occurs sometimes at potentially dangerous times like when i have set of to go around a roundabout.

surely i should be able to use this combination of gears??? I've just had the said bike into the LBS (not the one i bought it from) and asked them to set the front mech as i thought this might help. however within 5 min of leaving the shop the 'jump' from middle to small occured. It seems to happen because the chain is bending in towards the back of the bike when in that comnbination.

Is it worth me getting in contact with Edinburgh bicycle company as the bike is still under warranty??

PS - i know i could get the same combination using the small chainring and a smaller sprocket but that would seem to require alot more changing of the chainring than i am used to

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Mystique

Not sure there's an easy fix for you - The general rule is only use the smallest gear at the back with the biggest ring at the front & vice-versa.

Even if you could get the gear to "stick", you'd be putting a lot of sideways pressure on the chain which would (a) weaken the chain & (b) make it harder to pedal.

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Unknown

Depending on how many sprockets you've got, you may want to avoid the largest sprocket with the middle chainring. However, I don't think there's a reason why it should jump to the small chainring, mine doesn't and neither does my partners on our 8 geared bikes with triple chainsets.

Before leaving the lbs you should always give the bike a test before leaving properly. Take it back to them and have them do it properly.

Dunedin

nicksun

DLB,
You should be able to use the gears you mention without the chain dropping off. I regularly use that combination with no probs whatsoever.

Is there a chance the BB is too long? I don't know about these things but there's plenty on here that do.

Hope you get it sorted out.

Nicksun.

P.S. Post in know how, you may get more answers.

DLB

the LBS said maybe the BB was a little bit long but then said it couldn't really be much shorter!!!

BTW it's an 8 speed cassette AND i've reposted in 'know how' to see if there are any other suggestion...

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DLB

Having just been out on the bike the chain has just jumped from the middle to small chainring while the rear mech was on the 4th largest sprocket and so i'm going to take it back to the shop i got it from tomorrow.

thanks for the help.

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Garybee

It could be that the front mech is set up poorly.

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gaterz1981

The high screw on the front mech adjusted too much/too tight?? I have a pain of a job getting my new rear cassette and chain to index.

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msb123

In those circs i would start again setting up the front mech. dicsonnect the cable, check limiter screws, re-attach cable (making sure that lever is set to smallest chaniring) and then adjust. It shouldn't jump in the combination you mention, but you will wear your chain out very quickly if you put sideways pressure on it.

nmcgann

That's a gear that should be usable - on my bike that has a triple I rarely use the little ring, but I do use the middle ring/biggest sprocket combination quite a bit.

It sounds like either a worn middle chainring (and/or chain) or a too-long BB. It's unlikely that the front mech is the problem (assuming it isn't touching the chain when it jumps).

Some experimentation is going to be needed to fix it - you need a savvy LBS that is prepared to have a good go at it.

Neil

msb123

a rough way to check chain alignment is to put the chain on the middle ring at the front and check how it sits on the 4th and 5th rings (middle 2) at the back. if there is a sharpish bend in the chain rather than a slight curve off the chainring then the BB axxle may be too long. unfortunately it's a bit hard to describe, but have a look.

DLB

SORTED...

...and how pleased am i!!!!!

Took the bike back to edinburgh bike co in leeds (2 hour round trip) and explained the problem. The guy there (james - nice helpful chap) tried first to set up the front mech again and then asked me to go on a ride to check it out. No luck - problem still there. So i return to shop and ask him to try it out and would you believe it the problem disappears. So he has a tinkle and asks me to try again. This time i rode for 10 mins trouble free and though i was going to pack up and go back home when the problem occurs. So i ask JAmes to go for another ride and this time he encounters the problem. Bike then transfered to workshop where we manage to get the chain to jump twice in about a minute. At which point James take the triple chainset off and hey presto we see the problem. Somehow the middle chainring had bent towards the smaller ring and this was causing the chain to jump up of the middle and onto the small ring. Upshot was that James replaced the chainset completely and put new pedals on and so my bike is now rideable. Yippeee!!

Many thanks for all the help and suggestions posted by members.

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Tony666

So glad it worked out well for you.

DLB

cheers Tony

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photojonny

They are good aren't they? [:)]

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DLB

yes mate, and so is my bike now it's fixed. [:)]

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