Australian Cycling Forums - Bicycles Network Australia

I noticed last week that my rear gears were not moving to the smallest cog. It's not the adjustment screw as the derailleur will move far enough, it just seems the spring isn't pulling the derailleur to the last cog without some assistance. I do clean the bike about monthly and have put some oil on the derailleur but it is still reluctant. Any ideas?

The bike is a Giant flat bar running the usual flat bar shifters and Shimano Sora gears which have worked very well since I got the bike. The bike has done just under 20,000KM.

DS

Could be the cable is a tad gummed up, otherwise, the cable may need adjusting (loosening, or barrel on derailleur rotated clockwise a bit). Usually, your problems would be the opposite - the derailleur not shifting from high gear (small cog) to low gear (large cog) - when there has been a few miles and a bit of wear (cable stretch).

cheers

My money'd be on the last loop of housing being a little mucky. Doesn't take much...
Try the barrel adjuster first and if you get no joy, try shifting a few up the stack (on the stand of course), undoing the cable and cranking. If it drops neatly onto the small without hesitation then it's almost certainly cable gunk.

Of course being 20k kms old, the mech might be just a touch flogged out too.

Mulger bill wrote:My money'd be on the last loop of housing being a little mucky. Doesn't take much...
Try the barrel adjuster first and if you get no joy, try shifting a few up the stack (on the stand of course), undoing the cable and cranking. If it drops neatly onto the small without hesitation then it's almost certainly cable gunk.

Of course being 20k kms old, the mech might be just a touch flogged out too.

I am going to bet against our mate Bill, and put sixpence on a frayed cable at the shifter end.

After a clean yesterday it was shifting better today but I don't often get to the smallest cog.

It shifts well in the middle of the cassette and I have been fine tuning the barrel adjuster so I don't think it is that.

As for the suggestions that it could be a frayed cable at the shifter or gunk in the last part of the outer cable, there's real potential there. I did buy a new cable so maybe I'll fit it. Never done this on a modern bike (ie: indexed gears) before but I have the instruction sheet for the shifters and it looks pretty easy. Could take the opportunity to replace the outers as well.

Thanks for all the advice. Certainly a fair bit to go on.

DS

If the bike has done 20,000km def go for new inners and outers for the cables. I wouldn't event consider trying one or the other. The derailleur spring could be worn out after that length of service, when you remove the cable push the derailleur against the spring and see how well it snaps back, a new cable will help but may not solve the problem, I was surprised when I replaced my oldest derailleur with a new how much better the shifting was.

Fair point, I have pushed the derailleur around and it snaps back ok but not so well when it gets right down to the smallest cog. I'm thinking I'll wait until the end of the year when I have some leave and replace the inner and outer cables and pull the derailleur off and give it one hell of a clean and lube. Might change the hanger too it looks very slightly bent although I haven't hit the derailleur since I replaced the hanger a while ago.

DS

My 1996 daily rider is still using the original rear shimano derailleur, which would have done roughly 200,000km. Its gone through a lower pulley but nothing else.

When the bike stops shifting well, the first thing I do is change the cable and cable housing.

Its cheap, its easy and it works.

Start with the basics first.

stanzarallyman wrote:Its cheap, its easy and it works.

and dont wait for your christmas leave. Do it between entree and main course tonight.