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That plastic thing behind the cassette

RenegadeRick

98th percentile on my SAT & all I got was this tin
I busted a spoke and I'm gonna have to remove the cassette to replace it. Should I keep the guard behind the cassette?

I had looked up some advice on this guard previously, and based on that, I removed this part. Now sometimes my chain drops off into the wheel.

What are your opininions on this part? Should I put it back on when I replace the spoke? Simply adjust the rear deraileur limits properly instead?

Thanks!
 

binary visions

The voice of reason
Jun 13, 2002
22,100
1,150
NC
In theory, your rear derailleur should be adjusted such that you will not jump your chain off the cassette. Even if you have the plastic guard on there, your derailleur should be set up properly.

In practice, that part isn't hurting anything and protects your spokes if something bizarre happens and the chain jumps. It can accumulate mud, so if you're finding a lot of mud in there behind your cassette, you can pull it off. I usually pull mine off just because they're ugly :p
 

binary visions

The voice of reason
Jun 13, 2002
22,100
1,150
NC
RenegadeRick said:
What sort of things could cause this? It doesn't happen at home while I am working on the bike. It only happens while I ride it.
Make sure your limit screws are set right and that everything is aligned properly - that is, your dropouts are straight, your derailleur hanger is straight, and your derailleur cage isn't bent. Could be an issue with your cassette, too, so check your biggest cog and make sure nothing is bent or broken.
 

Vulcan

Chimp
Oct 24, 2004
66
0
I've had those dumb gaurds removed on just about ever bike I have owned. Never had a problem.
 

El Caballo

Chimp
Nov 21, 2004
61
0
East Bay, West Coast
I leave it in there. People make fun of me sometimes, but I make fun of them later when they have to replace half the drive side spokes because the chain got sucked behind the cassette.

It's only happened to me once, but that was enough to make me never want to deal with it again.
 

Spunger

Git yer dumb questions here
Feb 19, 2003
2,257
0
805
I took this off my bro's store bought bike. It was annoying me :)

But.....don't break it or tear it off. Take the cassette off and get it off the right way. You may mess something else up by just tearing into it.
 

b-Rad

Chimp
Feb 7, 2005
6
0
Take it off. It just creates a lot of unwanted noise/rattle.

*it will break off eventually anyhow.
 

Wumpus

makes avatars better
Dec 25, 2003
8,161
153
Six Shooter Junction
RenegadeRick said:
What sort of things could cause this? It doesn't happen at home while I am working on the bike. It only happens while I ride it.
One of the biggest causes of it jumping behind the cassette is shifting under load. :nope: I haven't had it happen in years because if I have to shift on a hill I soft pedal one revolution of the cranks until it shifts then go.
 

mshred

Monkey
Aug 6, 2006
525
0
Posts: 26,935
i bought my bike brand new and it didnt have one. i asked my LBS if it was normal (cause my costco bike had one) and he said it was normal. if i wanted he could put one on.bah who needs them? they look ugly and they just get in the way. in my opinion:D
 

dhphoto

Monkey
Jun 1, 2006
116
0
Lynchburg VA
Toss that stupid piece of plastic...like most of these guys have said, its not worth a damn. I've only had my chain pop off the top cog due to an improperly set limit screw. And part of the problem also came from a crappy sram cassette, which has since been removed and replaced. But really, you're gonna have to replace spokes along the way at some point, so there's no way around that.
 

Boxxer

Monkey
Jul 18, 2005
856
2
Dirty South
Heres the bottom line:

If your bike is neglected and you cant tweak a rear derailleur by yourself, leave it on.

If youre cool take it off. I havent run one for 15 years on as many bikes and never had a problem. I DH, DJ, park and even ride road.

Its akin to the devision between lycra and baggy, between urban and street and between those who think they know and those who actually do.

Cheers!
 

el_gordo

Chimp
Jun 13, 2004
87
0
DC (Da Capital)
Isn't the spoke material a factor??? I.e. it needs to be there on Mavics with the aluminum spokes -- otherwise a jumped chain will cause serious damage. On the other hand, I had the chain get stuck between the cassette and spokes on a Bontrager with the disc removed. It knocked the paint off, but no serious damage.
 

novarider

Chimp
Aug 17, 2005
34
0
Northern VA
it supposedly there to stop the chain from jumping off and secondarily to keep mud and guck out of your cassette. whats it gonna hurt to leave on?
 

alaska

Chimp
Oct 19, 2006
16
0
yeah , chances are it will just keep getting more and more beat up..just be sure to set you're limit screws up right so the chain doesn't fall in there.