Sora rear mech

[rich p]

My wife's bike's jockey wheel bounces on the sprocket when in the largest cog and smallest chain ring. The rear mech is Sora and the sprocket has 32 teeth. The B(?) screw is fully tightened. Is this a compatibility problem? A mate reckoned that the Sora road mech should be replaced with an mtb one.

 

[llllllll]

Could be, according to this:

http://www.wiggle.co.uk/p/Cycle/7/Shimano_Sora_3400_Rear_Derailleur/5360033549/

the sprocket range is 11-27. Don't know if this would cause the symptoms you're describing though.

 

[Gerry Attrick]

Have you tried adjusting the B tension screw?

 

[RedBike]

I thought that shimano road mechs were limited to a 27 tooth max cassette. I suppose you could always use a longer screw but the chances are if you set it to clear a 32tooth sprocket it will be miles above the smaller ones.

Worth fetling a bit before replacing the mech to see if you can get it to work.

 

[Smokin Joe]

Have you tried adjusting the B tension screw?

The clue was when he said the B screw was fully tightened

 

[Gerry Attrick]

Oh boy....I knew I should have read the OP properly. Thing is, I've been led astray by Tom Woods tonight.

 

[fossyant]

New Mech, or smaller sprockets...heh heh !!!

 

[TheDoctor]

I can vouch than an Acera mech will work nicely with a 32 sprocket - got one on the Ribble bike...
Sora and 32T - no chance. Even 28 is pushing your luck a little.

 

[PatrickPending]

as above.... I think you need a long cage mech

 

[rich p]

Thanks all. New mech it is!

 

[vernon]

I can vouch than an Acera mech will work nicely with a 32 sprocket - got one on the Ribble bike...
Sora and 32T - no chance. Even 28 is pushing your luck a little.

Sora long cage mechs work fine with a 28 tooth sprocket. The original poster needs to get a mountain bike rear mech to cope with 32 teeth. I use an Alivio mech on my Dawes galaxy and have had 100% reliable and adjustment free use from it over the past three years and around 10,000 miles.

 

[rich p]

Someone has suggested to me that a long cage Tiagra rear mech would work with a 32 tooth cog. Is this the case or do I need the mtb one?
Thanks

 

[peanut]

has this just suddenly started to happen ?and its been all right previously
or have you just fitted this seup recently?

If its been ok up until now I would suggest you check that the spring in the rear mech isn't weak or broken.
Take the rear wheel out and check the return spring strength of the rear mech .
Also check that you have the correct chain length . A picture would be useful

 

[vernon]

Someone has suggested to me that a long cage Tiagra rear mech would work with a 32 tooth cog. Is this the case or do I need the mtb one?
Thanks

The maximum sprocket size for Tiagra rear mechs and indeed, all the other Simano road bike mechs, is 27 teeth though you might get away with 28 teeth as I did using a Sora mech. The Campagnolo rear mechs have a 29 tooth limit.

I'd go down the mountain bike route. My Alivio mech is giving great service on my Glalaxy but is limited to 8 speeds. Deore is probable the best bet, long cage if you are using a triple chain ring.

 

[rich p]

has this just suddenly started to happen ?and its been all right previously
or have you just fitted this seup recently?

If its been ok up until now I would suggest you check that the spring in the rear mech isn't weak or broken.
Take the rear wheel out and check the return spring strength of the rear mech .
Also check that you have the correct chain length . A picture would be useful

It's a new bike built by someone who has used us as guinea pigs to a certain extent. He has made a few mistakes but is happy to sort the problems out. I want to be fore-armed before I take it to him though, hence the questions.