Mountain Bike Reviews Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 ·
Hey all, I tried posting this in the Shimano forum, but I figured I would turn up better help here. Tried searching, didn't come back with anything helpful.

Ok, here's the newb question: I've got a Deore LX RD-M571 rear derailleur and I've got a couple different problems with it, but that's not the point - I'm looking to just upgrade it. I've never changed out a rear derailleur so I don't know what to look for, or anything about the specs. I'm looking specifically at the Deore XT series, but I have no clue what really distinguishes one from another, i.e. Conventional or Low Normal Return Spring, Standard or Low Shadow Profile, Medium or Long Cage.

So I guess I'm just looking for a quick Rear Deraillers 101 so that I know which one I should finally pull the trigger on.

Thanks for any and all help!
 

·
^ That's what I do
Joined
·
747 Posts
What exactly is wrong with the derailleur you have now?

Now, to answer your question, the Shimano shadow derailleurs are designed to "hide" the pulley mechanism from hazards by positioning it behind the quick release or axle bolt. This makes it is less likely to be damaged during collisions or if you drop the bike on its side. Standard design derailleurs aren't positioned this way.
Article with picture of shadow vs. non-shadow derailleur

Short cage derailleurs have less chain capacity than long cage derailleurs. They can't handle as wide a range of gear ratios as a long cage. Here's a guide which explains it pretty well - http://www.beyondbikes.com/bb/tech/?section=rdr
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #3 ·
Man, I appreciate all of the literature Hopping! That answered just about everything. I was on google for at last and hour and a half trying to find something, I just couldn't put my thoughts into a descriptive word for google.

I just have on small question left now, what is the difference between Conventional - Low, Normal Return Spring.

Thanks again!
 

·
R.I.P. DogFriend
Joined
·
6,891 Posts
Low normal shifts in the opposite direction from conventional (high normal) derailleurs. If you have a conventional derailleur, it starts out on the ninth cog and as you shift (drawing the cable into the shifter), it moves toward first gear. Low normal is the opposite.

Some prefer to be able to grab a handful of gears in one direction over the other as you can do with rapidfire type shifters. With low normal, when you are going in the direction that you have to hit the trigger one tap at a time, it will be shifting from the smallest cog on the cassette to a larger one and you grab handfuls of gears (changes) going from big to small.
 

·
MTBR Member
Joined
·
3,008 Posts
You might be better off to just wait until the LX derailleur is not functional anymore. You are not going to notice a huge difference by just replacing the derailleur. Assuming you have deore shifters, you would be better off replacing those. Or even just get some quality teflon coated derailleur cable. I put some jagwire ripcord cables on my LX derailleur and noticed an improvement.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #7 ·
Thanks fisherman, I'm actually looking into some XT Rapidfire Plus shifters, too. As far as the rear derailleur, I couldn't tell you what exactly is wrong, as I'm not much of a bike-mechanic. It's only the rear, but if I try and shift up or down, chances are it won't budge, but if it does, it's like a circa 1992 bike where it lags and finally catches. I've given it my expert once-over and it looks like everything is running properly, nothing is wrong with the shifters themselves, they are just getting a little sticky, it's just the derailleur getting stuck or stalls. :confused:
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #9 ·
I checked up and down the cables, from the shifter to the derailleur, without taking the shifter of I looked it over and everything moves smooth. I'll look at it again and spray some degreaser in there. Hopefully it will help, the bike's drivetrain has held up incredibley well thus far. If nothing else I'll take it over to the LBS.
 
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top