Good Directions on how to set up a rear deraileur

doobie919

Is it fairly easy for someone not very mechanically inclined. I just ordered a new rear deraileur, and would rather not pay to have it installed since funds are kind of tight now.

What needs to be done to set it up?

softlad

practically, there are only three things to consider..

correct cable tension - so that the lever does not over-shift/under-shift the chain
outer limit screw - so the chain does not fall off the top of the cassette
inner limit screw - so the chain does not fall off the bottom of the cassette

go and experiment..

doobie919

If I hadn't have messed up the pulley on my deraileur i have right now, i'd be out figuring it out. But that part is out of the question now. Can't wait to tinker around my the deraileur till I get it right.

Is it an easy task to master?

alfablue

Yes, it is easy.

Best look at Park Tools web site.

Also Shimano technical documents are helpful (if it's Shimano).

Basically, screw mech on to hanger with allen key
Fit chain
Set limit screws
Put shifter in highest gear (so least pull on cable)
Attach cable taking out slack
Tweak cable adjuster to get the tension right for sweet running and shifting

It is a five minute job if experienced, obviously you may be learning on the job, but as long as you follow the instructions by Park Tools carefully, you shouldn't go wrong. Famous last words...

doobie919

Thanks for the replies everyone, can't wait to get my deraileur to see just how un-mechanically inclined I really am.

bill57

That's three separate posts this evening about a rear mech - which is a fairly uncomplicated device. People could get bored with you very quickly.

Lagavulin

You may also find this video of use. It - along with Park website- was of assistance after I pranged my rear mech.

doobie919

bill57 wrote:

That's three separate posts this evening about a rear mech - which is a fairly uncomplicated device. People could get bored with you very quickly.

Well damn sorry. Didn't realise I was going to OFFEND anyone, and it's the internet anyways. I'm a inquisative young boy whose new to riding, need I say more. I know jack shit about derailleurs, so i'm asking the only people I know who are into cycles, which are you guys here at bike radar.

alfablue

not offended Doobie

doobie919

All's good then.:)

bill57

People will answer your question. You just need patience.

giant_man

This should be all you need:

http://bicycletutor.com/adjust-rear-derailleur/

Don't worry about comments on this thread about being patient. We all need to learn these things and that is precisely what this forum is about. You don't need bill57 to undermine your confidence. Just take the advice and follow it slowly and thoroughly and you'll be fine.

redddraggon

I don't know how successful you will be getting a 7900 derailler working with (what I guess is) "old" 9/10-speed shifters.

I've seen 7900 shifters work with a 7800 mech, so perhaps the reverse will work. But I think it's not meant to work :?

John.T

The 7900 and 7800 cable pull ratios are different so you may have trouble there. You will need to use the correct shifters.

alwaysOTB

The 7900 rear is the same cable pull as 7800. Fronts not meant to work, and neither are the brakes. I think you'll have problems is you've got 9 speed shifters - dont know if you have or not?

doobie919

Shit I didn't even think about shifters.

I've got 8 speed shifters.

Wll I not be able to run my new deraileur till I get the right shifters?

rockmount

:roll: :roll: :roll: Doh !!!

doobie919 wrote:

shoot I didn't even think about shifters.

I've got 8 speed shifters.

Wll I not be able to run my new deraileur till I get the right shifters?

...No

doobie919

I've decided to cancel my order for my parts and go with a cheaper deraileur that is already compatible with the system I have, I don't need top of the line anyways.

Mettan

Uhmm......re-setup mine tonight - didn't reliase (until now) how important cable tension is - traditionally thought the barrel adjuster would sort all - but no - found tonight, that literally allowing the cable to slacken or tighten (with nut/spanner pliers) by as little as 1-2mm either way "under the nut" will make the chain hugely over or under-shift - live and learn.