Ultegra rear derailleur problem

[Swordtail]

I just got a brand new Giant TCR 0, to replace my 20 year old Giant. I'm having problems with the Ultegra rear derailleur. On the small front cog, when changing from the largest rear cog to the second largest, the chain isn't quite going far enough and is riding up on the large cog. This is on a stand, maybe it wouldn't with my weight on it?

I've set the High and Low screws and have been fiddling with the barrel adjuster on the cable. It seems if I get the large cog end working, the small cog end isn't quite right. Is it possible something needs doing with the "B" adjuster screw? Or should I give in and take it back for the shop to look at (always prefer to opportunity to learn something!)

Cheers!

 

[ianrauk]

check out this excellent vid as to how to adjust your rear gears.
It explains the whole process inc. the high and low screws.

 

[RecordAceFromNew]

If the limit screws put the mech at the right places on the extreme cogs, and if the cable tension is ok, then the other possible cause is the cable is wrongly clamped, see pic at step 2) here.

 

[youngoldbloke]

If the bike is brand new you should expect the gears to be set up properly. After all this is a £1K bike, not a BSO. I would take it back to the shop

 

[Swordtail]

Thanks for this, the video was pretty good. I followed it which has helped a bit. It still seems very hit and miss going between the smallest and second smallest cog. I'd have expected Ultegra components to be more solid on gear changes. It'll do for now and I'll get the bike shop to look when it has it's one month check up. I agree, I did not expect a 1k bike of this quality to have problems, but I guess anything new sometimes isn't perfect from the outset.

 

[MattHB]

Things stretch, springs bed in. Even a 3k bike has a free first service for those very reasons don't worry about it.