Mountain Biking - Rear derailuer

Hello everyone...

I'm basically a newb when it comes to bike parts and I'm in need of a new rear derailuer for my Trek 4300. I would like to get a deore but not sure what model or if it would work on my bike. If any of you could help me on what derailuer to purchase that would be great. I would like to upgrade from Alivio.

Here is a link to the 4300 http://www2.trekbikes.com/bikes/bike.php?bikeid=1018600&f=18

I think you can use 9 speed derailleurs with an 8 speed set up. Just be sure to get a long cage, non rapid rise version.

Can somone give me a link to somewhere to buy the correct model.

Can somone give me a link to somewhere to buy the correct model.


http://www.universalcycles.com/shopping/product_details.php?id=9869&category=72

Hello everyone...

I'm basically a newb when it comes to bike parts and I'm in need of a new rear derailuer for my Trek 4300. I would like to get a deore but not sure what model or if it would work on my bike. If any of you could help me on what derailuer to purchase that would be great. I would like to upgrade from Alivio.

There's absolutely nothing wrong with that. However, unless your rear derailleur is broke, why do you need to upgrade? Check out Sheldon Brown's page. The function of the device is very simple and having one that works well is mostly to do with how well-tuned it is. Of course, there are really crappy ones out there but I do not beleive the Alivio is one of them. One that is out of tune can easily give the false impression that the problem is due to the component's inferiority.

Lower end mechs use lower quality materials so they tend to wear out faster and not shift as crisp. You can definitely feel the difference between alivio and XTR... no doubt about that. I can feel a difference between even XTR and X.0. It isn't all marketing hype, it's just mostly marketing hype :)

This one would work: http://www.performancebike.com/shop/profile.cfm?SKU=21141&subcategory_ID=5111

whats the diff. between rapid-rise, and the "non"-rapid rise one?

http://www.universalcycles.com/shopping/product_details.php?id=9869&category=72

Ahhhh!!!!! $36!!!! I can get XT for that price!!!!

Deore
http://www.jensonusa.com/store/product/RD703A02-Shimano+Deore+Rear+Derailleur+M510.aspx

http://www.jensonusa.com/store/product/RD507A00-Shimano+Deore+M510+Rear+Derailleur+Oe.asp

LX
http://www.jensonusa.com/store/product/RD604A01-Shimano+Lx+Rd-M580+Rear+Derailleur.aspx

XT
http://www.jensonusa.com/store/product/RD707A04-Shimano+Xt+M750+Series+Rear+Derailleur.aspx

whats the diff. between rapid-rise, and the "non"-rapid rise one?

Standard derailleurs will rest under the smallest cog when the cable is disconnected and rapid rise rest under the largest cog.

Lower end mechs use lower quality materials so they tend to wear out faster and not shift as crisp. You can definitely feel the difference between alivio and XTR... no doubt about that. I can feel a difference between even XTR and X.0. It isn't all marketing hype, it's just mostly marketing hype :)

This one would work: http://www.performancebike.com/shop/profile.cfm?SKU=21141&subcategory_ID=5111

The rear mech fitted to most bikes- will work well enough to change gear. Unfortunately the cheaper ones will wear out quicker. Get a bit of play- or too much play, and it stops changing crisply. Alivio is not the best Derailler around but until it starts causing a problem, there is no need to replace or upgrade it.

I personally use XT and don't have many problems with it- However- I do replace the rear derailler about every 12 months. A couple of years ago I got an XTR rear derailler on sell out and it is great- After 12 months use- it had no play and no slop in it and on checking it- it will be doing a 3rd year. Haven't noticed a better gear change but the life of it is great.

I put an XT on one of my 4300's and an LX on another. And to be honest i can't tell any difference in performance from the original Alivio. But if your Alivio is broken, just as well put on a long cage XT and be happy with it. They aren't that expensive.

I'm not sure what my problem is. My Deore shifts cleanly through all gears, but my chain slips into 7 from 8 no matter how I adjust it. The derailleur and sprocket are both stock, and yes I know how to adjust the screws that limit the range of the derailleur. I don't see any wear on either part, the only thing I can think of is maybe the spring in the Deore is wearing out and is unable to keep tight on that gear. Any suggestions?

Sounds like the cable might be a bit too tight.

Bent hanger (on frame) or bent rear mech are both likely. The pulleys on the rear mech should be vertical - if they are not, then something is wrong.
Check that, cable tension, limits again, and make sure the cable is clamped on the correct side of the clamp bolt. Clamping it on the wrong side will cause the mech to pull differently.