Shimano 105 compact gear issue

1964johnr

New bike with 105. I do not seem to be able to set the barrel adjuster so that I can switch from the big ring to the little ring and use most of the gears without getting front mech chain rub. Also, I cycle my normal route on the flat for 20 miles on the big ring with no front mech chain rub problem. Then I switch to the little ring to go up hills and the front mech rub sets in. I can adjust the barrel as I ride to get rid of it, but when I switch back to the big ring the barrel needs more adjustment. Anyone any ideas how I can solve this issue. I would be happy if I could use six gears on the big ring and six gears on the small ring without the chain rub. I don't need the highest four gears on either ring.

NewTTer

Just take it back to where you purchased it from and tell them to set up the FD correctly. Fiddling with the barrel adjuster isn't going to help, that will just ensure sufficient cable tension to operate the FD. Its the limit screws that have the biggest impact. And the correct positioning of the FD in the first place.

dj58

Are you getting chain rub after using the trimming function of the STI shifter?, if so then as NewTTer says take it back to the shop for them to check over the setup.

paul2718

Are you using the 'trim' mechanism? You can make a part shift on the front which won't move the chain between rings, but which will allow you to use a wider range of gears without rub.

But it is quite likely your front mechanism needs adjusting. It's not that hard, look up the instructions on the Shimano 'techdocs' web site (which seems to be broken right now). Or take it back to the shop and have them reset things.

You should be able to get pretty much every gear without rub, although obviously the extremes are not recommended for extensive use.

Paul

1964johnr

Thanks for the replies. I don't think it has been set up correctly because the trim function doesn't seem to operate. Unfortunately it was a mail order purchase from Ribble so can't take it back to the shop. You all seem to be saying it's the front mech set up so I think I will read up on that and see if I can cure the problem by adjusting the limit screws and perhaps altering cable tension. If not i gues it's £15 at the LBS for them to sort it out. I'm pleased with the Ribble Gran Fondo apart from this issue. Light, resposive, looks good and their bike builder allowed me to be precise on choice of wheels, handlebars width, stem length, gearing etc.

paul2718

http://cycle.shimano-eu.com/media/techd ... 696762.pdf is the document you want. It's quite straightforward. Just don't force the lever.

Paul

Mad_Malx

Make sure the position (up down) and alignment of the derailleur is correct, then the stops and cable tension.

Also - on a new bike make sure the chainrings, BB and crank are all tight - if not there might be some play.

fat_cat

Have a look at you tube a quick search on there should set you off in the right direction. Certainly worked for me.

BrandonA

I wonder if the new cables have stretched and need a re-tweak. When I've bought new bikes the shops have expected this to happen and offer free check up within a 6 week period of purchase. I'd take it back to where you bought it and get them to re-adjust.