Help replacing DA7800 RD cage

[kgreene10]

I have one DA 7800 RD with a good cage and another with a good body and want to make one good one overall. I have an appointment with the LBS to do the work in 10 days, but wouldn't mind knocking it out myself ahead of time.

If it's a relatively straightforward set of tasks, could someone in the know tell me about them? In particular, are there any tricks to working with the pre-wound spring?

Thanks.

[oldpotatoe]

I have one DA 7800 RD with a good cage and another with a good body and want to make one good one overall. I have an appointment with the LBS to do the work in 10 days, but wouldn't mind knocking it out myself ahead of time.

If it's a relatively straightforward set of tasks, could someone in the know tell me about them? In particular, are there any tricks to working with the pre-wound spring?

Thanks.

Just a allen bolt, 5mm I think. Inner cage/pulleys off, unscrew bolt holding cage onto body. When you reattach good cage, start bolt, then pull cage/rotate toward front of bike direction, winding spring, then tighten bolt. Takes about 10 minutes if the cage/pulley if off, surprised the LBS can't do it 'on the spot'.

[aosty]

If you have trouble reassembling, it can be handy to have a second person hold the cage against spring tension.

[Gummee]

If you have trouble reassembling, it can be handy to have a second person hold the cage against spring tension.

+1

It can be a PITA to get the spring loaded, hold the cage down, switch to a wrench, etc. Having another hand holding the cage helps.

M
former owner of an XTegra rear derailleur and builder of one good XTR derailleur out of 3 junked ones.

[kgreene10]

Thanks guys. When I wind the cage/spring toward the front of the bike, approximately how many degrees do I wind it? Are we talking 90 to 180 degrees, one 360 degree revolution, or multiple revolutions? It may be obvious once I get in there, which I haven't done yet, but I figured I should check.

[Ralph]

Park Tool describes how to do it with pics.