Front derailleur beginner's problem

blueangel

Just got my bike back from servicing, and am finding that often when I click from the big ring to the smaller ring the chain does not make it all the way across, so that I am pedalling without engaging the chain. It's a Shimano 105 set up with a 10-speed cassette at the rear. Shifting to high gear is no problem, but when the above mis-shift occurs pushing on the down-shift lever has no effect.

I am completely unskilled with regard to bike maintainence, so before I start messing around with the derailleur limit screws and wrecking the whole deal, I thought I'd ask for advice. Does this seem like a problem that would be corrected by loosening the low gear limiting screw? Is it likely to be a problem with the setting of the down-shift lever? Should I just resign myself to the loss of riding-time involved in taking the bike back to the LBS?

Many thanks for your words of wisdom.

PHcp

There should be no reason to touch any of the adjusting screws once it has been set up once. All other adjustment should be with the cable. It is possible that yours hasn’t been set up properly, though it’s unlikely.
Before doing anything else you need to determine if whether it’s the mech or cable. The easiest way to do this is to remove the cable and move the mech by hand. Only if you can’t move it to the right position should you make adjustments. The Park Tool website gives clear instructions
http://www.parktool.com/repair/readhowto.asp?id=75

mea00csf

If you've only just got it back from serviceing and you're local to the shop, take the bike back in and tell them it's not shifting properly. Surely you put it in for a service to get the bike working as good as new, and payed money for that so they should put it right, it'll prob only be a 5 minute job for them.

stevec205gti

PHcp wrote:

There should be no reason to touch any of the adjusting screws once it has been set up once. All other adjustment should be with the cable. It is possible that yours hasn’t been set up properly, though it’s unlikely.
Before doing anything else you need to determine if whether it’s the mech or cable. The easiest way to do this is to remove the cable and move the mech by hand. Only if you can’t move it to the right position should you make adjustments. The Park Tool website gives clear instructions
http://www.parktool.com/repair/readhowto.asp?id=75

Or you could just see if the cable goes slack when you change to the little ring - if it's slack the front mech isn't moving far enough (and can be usually be made to shift over far enough by adjusting the screw) whereas if the cable remains tight then it's that that's preventing the gear change (in this case the cable needs adjusting either by the small adjusters in the cable run, or be slackening off the cable) - you shouldn't need to remove the cable straight away.

The Shimano website has very good guides to setting up their equipment and a quick look may help you get to grips with what is going on a bit better

Pagem

mea00csf wrote:

If you've only just got it back from serviceing and you're local to the shop, take the bike back in and tell them it's not shifting properly. Surely you put it in for a service to get the bike working as good as new, and payed money for that so they should put it right, it'll prob only be a 5 minute job for them.

agreed. you payed for this service and it's technically incomplete.

blueangel

Thanks for the links and the input everyone. It does look like a problem with cable tension rather than the limit screw adjustment. I know the LBS will sort it out, but I was hoping I could save time (possibly a disastrous miscalculation) and that I could improve my understanding, maintainence and appreciation of the bike by having a go and getting stuck in.

Having said all of which the shop can fit me in tomorrow and it's my half day.

Best wishes,

blueangel