plastic thing behind cassete

[bigacorn]

Is the plastic thing above the sprocket (cassette) with the most teeth necessary?

I ask because my one always breaks and then rubs against the cassette.

The bike store said it was necessary. And keeps on putting really thin crap ones. (broke 3 so far)

i think i heard someone call it a pie plate before

[Kalgrm]

Assuming you have your derailleur adjusted properly, you don't need the pie plate.

[cynicism]

It's there to protect the LBS from warranty claims.

[/cynicism]

Cheers,
Graeme

[sogood]

It's also commonly called the "dork disc".

[justinfox]

If you want to remove it (because it's ugly) but don't want to run the risk of the chain ever getting caught between the back of your cassette and spokes, try locking out your big cog on your rear cassette. If you know how to tune a bike, it's very easy to do, all you need to do is adjust your limiting screw so that the chain never goes into the top (largest) cog on the rear cassette anymore.

[Kalgrm]

That's a bit extreme. If you know how to tune your RD, it's an easy job to stop it going beyond the big cog and still retain the use of it.

Cheers,
Graeme

[trailgumby]

Nathan Rennie does it, apparently. I guess the logic is that if you whack your rear DR on a rock you've got a bit of leewway before it takes your spokes out. Judging by what that guy does on a DH bike it's probably a lesson learned from experience.

[Mulger bill]

Less of an issue on a DH bike tho'. Stomper don't need no low gears

Shaun