Candlesticks

I needed to replace my rear derailleur last fall so I bought a new Shimano Alivio and I can't figure out why it's not shifting up to the top 3 low gear cogs (I think that's how you say it lol). Adjusting the screws and wire tension doesn't seem to do a whole lot. I probably bought the wrong derailleur for it? Or just plain fail at setting it up :P.

I've got a 06 Trek 4500.
Stock Derailleur was a Shimano Deore RD-M511 (9 speed).
New Derailleur is a Shimano RD-M410 (8 speed).

I also never understood why the stock was a 9 speed, when you count 8 cogs on the rear cassette. Anyways, I'm pretty new to this stuff so any advice would be helpful.

Bill Kapaun

https://www.parktool.com/blog/repair-...illeur-systems

Airburst

Firstly, with Shimano, up to 9-speed systems the derailleur doesn't care how many speeds you have on the rear, that's only determined by the shifter. No rear derailleur is a "9-speed".

As for the setup, Park Tools have a tutorial on just this here.

dsbrantjr

I'll bet dollars to donuts that you didn't have the shifter in the position which lets all of the shift cable out when you attached it to the derailleur.

Candlesticks

I can't remember what exactly I did since it was a few months back. But I'm sure that could be the problem. I remember it seemed like my shifter tightened up like it maxed out already.

aramis

yeah just start from scratch. Loosen cable, shift to smallest cog on shifter with cable disconnected. Set low limit, connect cable, set high limit, adjust b-screw, then adjust tension. There's a million nice tutorials on how to do it. I usually just get the shimano tech sheet and follow the order/cog selection they have and it gets it pretty spot on, usually just have to fiddle with the tension at the end to get the shifting perfect.

If you can manually push the rear derailleur up to the highest cogs without the cable connected then it's a shifter/cable issue usually. If you can't get there then it's a limit screw issue.

fietsbob

fitting a new RD, The stroke limit screws are adjusted by pushing the pulley to be under the last cog.

By hand.. adjust the screw so It stops directly under that cog

likewise so as to stop directly under the smallest cog,

Then hook up the cable and feed the chain through the pulleys..