Shifts up but not down - what gives?

mudcow007

my bikes has been developed an issue in that it shifts up fine, but not down like the dérailleur doesn't have enough pull in the spring to pull the cable - if that makes sense?!

bike is 4 months old so derailleur should still be ok

any ideas?

MrChuck

Drag in the cable?
If the wire has too much drag on the outer when too much crap gets in there it can be too much for the spring to overcome. Things like too tight a loop before the cable enters the mech can make it worse.
Easily checked by unhooking the cable from the mech- obviously you'll need to set your gears up from scratch if you do this though!

cooldad

Cables. And I think you mean it shifts down fine - down = lower gear/bigger cog. Up=higher gear, smaller cog.

FoldingJoe

When you say "issues", do you mean doesn't shift at all, or is just hesitant?

Seen as though your bike isn't that old it could just be cable stretch, so you may need to tighten the cable slightly.

phy2sll2

Have a look inside the shifter, you may find the cable has frayed and is getting stuck when you 'release' the tension on shifting up.

mudcow007

thanks for the replies i reckons i need about a 1/4 of a turn on the barrel adjuster

as it seems to be getting noisier by the day, so it must be cable

just threw me the way it was ok shifting up (going from say 5 sprocket to 7) but going down it wouldnt shift unless i shifted down again an it would clunk down

bails87

So it will easily shift onto a phsyically smaller (harder) cog, but not to a physically larger (easier) cog?

Sounds like the cable is sticking. Unhook the outers from the cable guides, see how freely they move along the inner cable. Replace/WD40 as necessary.

The Rookie

Unless it's rapid rise, cables usually cause an issue going to a up, the OP is having issues going down through the gears when the shifter would be pulling cable, indexing would be most likley, unless its an RR of course!

Simon

bails87

The Beginner wrote:

Unless it's rapid rise, cables usually cause an issue going to a up, the OP is having issues going down through the gears when the shifter would be pulling cable, indexing would be most likley, unless its an RR of course!

Simon

You're right, my brain was muddled!

In that case, I agree with you, a bit of cable stretch knocking the indexing out is most likely.

mudcow007

ok ok you both earned your cookies today



i have been playing around witht e barrel adjusters an i think ive sorted it

fanks