Rear Derailleur

[jbludford]

I have a Cannondale 1987 Backlighting, with Suntour Accushift Derailleur. I just purchased the Shimano ST-A070 Road Shifter - 2 x 7-Speed. I’m having shifting problems with the middle gears on the rear derailleur, I like my 7 speeds and the Shimano cassette is in great shape. The high/low gears are in good shape. I would like to know what rear derailleur? I was told that the Tourney TX35 Rear derailleur (6/7 Speed) was what I need. I was also told that my chain could be the problem. I still think it is the derailleur.

[attachment=4087]
Thank you for any help you have

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I have a 50 Mile ride in may would love to solve the issue before then

[torquecyclerepairs]

(04-18-2013, 11:10 PM)jbludford Wrote:  I have a Cannondale 1987 Backlighting, with Suntour Accushift Derailleur. I just purchased the Shimano ST-A070 Road Shifter - 2 x 7-Speed. I’m having shifting problems with the middle gears on the rear derailleur, I like my 7 speeds and the Shimano cassette is in great shape. The high/low gears are in good shape. I would like to know what rear derailleur? I was told that the Tourney TX35 Rear derailleur (6/7 Speed) was what I need. I was also told that my chain could be the problem. I still think it is the derailleur.


Thank you for any help you have

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I have a 50 Mile ride in may would love to solve the issue before then

Have you got a pic of the rear mech?

[DaveM]

The Suntour rear derailleur would definitely be the prime suspect for the problem. You generally can't mix suntour and shimano on anything idexed.

I'm pretty sure you could use any shimano derailleur built to handle anything from 7 up to 9 speeds without an issue.

It may be worth it to spend an extra $10-20 and step up to a Tiagra or even 105 derailleur. BUT, if you need the type that has a hook that goes under the wheel's axle nut, Tourney may be the highest you can go.

Unless the cassette is pretty new, changing the chain may give you trouble. It's common to change cassette and chain at the same time. If the chain isn't "7 speed compatible" it could be an issue, but it sounds like you've have 7 for a while and just got new shifters?

[1FJEF]

My Bianchi 7spd cogs & derailleur with Accushift will not work properly with Shimano shifters. The spacing is different with the Suntour cogs, period. It's different from Shimano.
You have a Shimano/SRAM Cassette with the Accushift derailleur & Shimano shifters, I don't see why there wouldn't be a chance of that working. You should have replaced the chain with the cassette so I don't know what's left except a new rear derailleur.
I wonder if the cassette is worn from using it with the suntour shifters. Change chain & cassette at the same time.
Cheap chain, light duty rust resistant.
Better heavy duty chain.
Cassette.
Cheap RD with hanger.
Post a picture of the rear derailleur area.

[nfmisso]

I agree with Jeff - except on the cassette - I have had two bad experiences with Shimano freewheels/cassettes; and had excellent experience with DNP, Sunrace and SRAM. Both Shimano units had spacing issues.....
http://www.amazon.com/SRAM-PG730-Speed-Cassette-12-32T/dp/B000NNQJ5O/
http://www.amazon.com/SunRace-CSM63-7-Speed-Bicycle-Cassette/dp/B002G340LE/