Is my chain too long?

[scoostraw]

I'm hoping you guys can help me.

I picked up a road bike for someone and was going thru it just to make sure everything was ok with it. It won't up-shift from the lowest gear on the rear derailleur. When it's in first gear the bogey wheel is right down on the sprocket - and I think that's what's preventing it from shifting. The derailleur has no B-screw adjustment. Can I correct it by shortening the chain?

Thanks!

[nfmisso]

pictures needed. more information about the derailleurs and bike needed.

probably not a good idea to shorten the chain.

[scoostraw]

Thanks Nigel,

Here are photos of the rear derailleur and drive train:

http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/derailleur_6.jpg

http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/derailleur.jpg

http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/derailleur_2.jpg

http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/derailleur_5.jpg

http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/derailleur_3.jpg

http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/derailleur_4.jpg

I eliminated the shifter cable as a cause by disconnecting it. It just doesn't want to come off the large cog by itself. A nudge by hand and it is fine - the spring in the derailleur will then pull it all the way onto the smallest cog.

If you have any thoughts I would appreciate it.

Thanks.

[nfmisso]

Based on this:
http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/derailleur_4.jpg

it is time to replace the derailleur; because it's internal springs are no longer working properly. You could try rebuilding it, but the replacement springs would probably cost more than a new derailleur if you could find the right spring(s).

[scoostraw]

If I don't rebuild it, can you point me in the right direction regarding an inexpensive modern replacement? This bike has 5 speeds on the hub. - Ken

[nfmisso]

Any 5/6/7 speed Shimano derailleur will work for you.

This one for example:
http://www.amazon.com/Shimano-Tourney-TX55-Derailleur-Speed/dp/B003ZMH69S/

My commuter has a TX51; recently replaced in their line by the TX55; works well.

You should also replace the chain at the same time; follow the instructions that come with the derailleur to set the chain length.

[scoostraw]

(07-20-2011, 11:07 PM)nfmisso Wrote:  Any 5/6/7 speed Shimano derailleur will work for you.

This one for example:
http://www.amazon.com/Shimano-Tourney-TX55-Derailleur-Speed/dp/B003ZMH69S/

My commuter has a TX51; recently replaced in their line by the TX55; works well.

You should also replace the chain at the same time; follow the instructions that come with the derailleur to set the chain length.

Nigel,

You were 100% correct. My LBS sold me a Shimano RD-TY18 GS derailleur for $10. It bolted right up and works perfectly. Here is my "after" photo:

http://i600.photobucket.com/albums/tt86/scoostraw/inlet%20hosting/shimano_derailleur.jpg

What is the main difference between this one and the one you mentioned?

Thanks again.

[nfmisso]

The RD-TY18 was discontinued several years ago - but other than that, there aren't any significant differences.