# Bit of plastic behind the cassette?



## SamN01 (15 Jul 2010)

I bought some new wheels and a cassette. My current wheel has a plastic disk behind the cassette. What is it for and do I need it? Do I need to buy one for the new wheels? Stupid question from a newbie I know but any answers appreciated.


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## HLaB (15 Jul 2010)

The plastic disc is there to stop a poorly adjusted mech shifting down past 1st gear and throwing the chain into the wheel. With a properly adjusted mech this will never happen so you don't really need it and a lot of folk tend to remove it.


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## SamN01 (15 Jul 2010)

Brill thanks!


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## crankyhorse (15 Jul 2010)

If the chain does go in to the wheel it can damage the bike and send you flying. 

I had that happen years back and I will not buy a bike without one. Especially since my next bike will be a C2W from Halfords


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## xpc316e (15 Jul 2010)

crankyhorse said:


> I had that happen years back and I will not buy a bike without one. Especially since my next bike will be a C2W from Halfords



I bought a new bike recently and the first thing I did to to it was to remove the plastic disc by attacking it with a pair of sidecutters. I know why it's there, but I make sure that the rear mech is properly adjusted so that it doesn't shift into the spokes. I don't wish to be condescending, but I regard a plastic disc (on a decent bike) as something as a 'badge of shame'.


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## SamN01 (16 Jul 2010)

The reason I asked is that I am also swapping the 105 11/25 cassette for a ultegra 11/25 cassette myself, is the rear mech likely to need any adjustment?


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## Sheffield_Tiger (16 Jul 2010)

The one that came on my bike can stay on my bike. It's hurthing nothing. I have enough to do without removing the cassette to get the disc off, and like my bike too much to deal with things by smashing them off


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## Chrisc (16 Jul 2010)

Snipped mine off with scissors.


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## Gixxerman (16 Jul 2010)

The bike snobs would call it a "pie plate" and ridicule you for still having it on your bike, and treat you like a social outcast and probably refer to you as a dork.
I personally can't see anything wrong with it and it does perform a valid function (albeit a mostly redundant one for correctly setup bikes).
I still have mine attached and couldn't care less what people think about it.


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## Rip Van (16 Jul 2010)

Gixxerman said:


> The bike snobs would call it a "pie plate" and ridicule you for still having it on your bike, and treat you like a social outcast and probably refer to you as a dork.
> I personally can't see anything wrong with it and it does perform a valid function (albeit a mostly redundant one for correctly setup bikes).
> I still have mine attached and couldn't care less what people think about it.



+1


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## Captain (16 Jul 2010)

I have it on mine because I don't see the point in taking it off. 
hell I could even paint it a funky colour to make it cool. 

Why do people take it off when it could save you a fall, chain, some paint etc..?


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## xpc316e (16 Jul 2010)

Captain said:


> Why do people take it off when it could save you a fall, chain, some paint etc..?



The last time I overshifted a chain into the spokes because of a poorly adjusted rear mech was about forty + years ago, so if I don't see a need for it - it need not be there. On a similar note I have three bikes; two of them do not have mudguards. I acknowledge that they can serve a really useful purpose, but if I do not intend to ride that bike in the wet, what need is there for them?


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## SamN01 (16 Jul 2010)

But will the mech need adjusting or not?


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## HLaB (16 Jul 2010)

SamN01 said:


> But will the mech need adjusting or not?



You are putting an identical cassette (just one which is a little lighter); if you never experienced the chain going into the wheel before you will not require new adjustment.


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## MJN (16 Jul 2010)

HLaB said:


> You are putting an identical cassette (just one which is a little lighter); if you never experienced the chain going into the wheel before you will not require new adjustment.



Wise words! 

To Sam, it will definitely be worth you checking and adjusting if required as a matter of course just in case there is a difference in theory and practice. Furthermore, given how straightforward it is to do there's little reason not to.

If you're unsure how to do it then I can appreciate that it may seem like a daunting task, however there are plenty of guides around, not to mention plenty of willing people on here!, to help you to do it.

Mathew


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## tiswas-steve (16 Jul 2010)

Helpppppppppp !! I really am in a pickle here, do I keep the " pie plate " on or off ?? ................. Ill leave it up to you guys on CC, first ten yups or nopes wins. I shall perform a sacrificial ripping off of the object at twilight if need be. My rep is at your mercy.


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## MJN (16 Jul 2010)

tiswas-steve said:


> Helpppppppppp !! I really am in a pickle here, do I keep the " pie plate " on or off ?? ................. Ill leave it up to you guys on CC, first ten yups or nopes wins. I shall perform a sacrificial ripping off of the object at twilight if need be. My rep is at your mercy.



C'mon Tiswas-Steve, don't follow the biggest herd of sheep - decide for yourself!

(if you insist, mine's a 'keep it on'... )

Mathew


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## Gerry Attrick (16 Jul 2010)

The vast majority of bikes don't have them. Does that help?


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## fossyant (16 Jul 2010)

SamN01 said:


> But will the mech need adjusting or not?



Unlikely....a slight tweek maybe of the cable adjuster.

All you need


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## g00se (16 Jul 2010)

OK, so for my vote and if it were me... take it off.


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## P.H (18 Jul 2010)

Gerry Attrick said:


> The vast majority of bikes don't have them. Does that help?


I bet the vast majority of bikes do have them


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## youngoldbloke (18 Jul 2010)

You can always set up your rear mech limit screw so that you can only change down to the last but one large cog. Hey presto! This leaves a safety margin without the need for embarrassing plastic discs.


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## ian turner (18 Jul 2010)

Keep it.
There's no benefit in removing it.
It's hardly the equivalent of stabilizers.
There's no embarassment unless you hang out with the cycling equivalent of the post closing
supermarket boy racer crowd.


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## tiswas-steve (19 Jul 2010)

Just letting you guys know, on Sunday I let rip with a pair of scissors on the mentioned bit of plastic ........... strange ......... bike looks just that bit more butch now.


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## Gixxerman (20 Jul 2010)

Couldn't really give a stuff either way.


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## Willo (20 Jul 2010)

My Allez is still sporting its plastic disc....if Schlek's chain can come off, mine might do at some point as I'm attacking nothing other than my own heart going up the wye downs in the granny ring :-)


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## dodgy (20 Jul 2010)

Just an opinion. 

If you have to hack off the disk because you lack the tools, I would hazard that you should keep the disk on.


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## Dan B (20 Jul 2010)

P.H said:


> I bet the vast majority of bikes do have them



How about if we limit the survey to bikes that have been ridden more than 40 miles in any given six month period?

I mean, really, it's like wearing elbow pads to go roller skating


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## Gixxerman (21 Jul 2010)

coruskate said:


> How about if we limit the survey to bikes that have been ridden more than 40 miles in any given six month period?


My bike still has it fitted.<br>I have had the bike for just over a year and I have done getting on for 3000 miles in that time, including a 100 miler.
So be very careful with your generalisations.


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## Ticktockmy (21 Jul 2010)

SamN01 said:


> I bought some new wheels and a cassette. My current wheel has a plastic disk behind the cassette. What is it for and do I need it? Do I need to buy one for the new wheels? Stupid question from a newbie I know but any answers appreciated.



I have removed mine, not because I see anything wrong with it being there, mind they can look unsightly after a while. When I am touring, as a quick fix if I break spokes on that side, I carry a few spokes which I have cut the head off, and have put a kink in place of the head, thus is a quick get rid of the broken spoke and slot the new temporary spoke in its place, saving the hassle of having to remove the Cassette, take about the same time as to repair a puncture. If the disk was left in place then it would be hard to replace the spoke. So that my two penny worth, and a tip for those new to touring.


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## battered (21 Jul 2010)

Ah, the infamous dork disc. It generates nearly as much noise as a helmet debate. Not bad for 50grams of plastic.

I have one on my MTB, it came with it and I won't be removing the cassette to take it off. MTB cassettes get filled up with gunge anyway and shifting can be unreliable. I haven't seen any MTB wheel at the end of its life without evidence of a chain dumping. I don't bother with the roady, I keep it clean and well adjusted and hope for the best. If it had come with one, no doubt it would still be on it. I have better things to do on my bike than worry about what I look like on it, or what other people think. I'll look up the road, not in reflections in shop windows. ;-)

If Schleck's chain can come off (was his bike not adjusted properly?) and the lack of a chain guard cost him a stage, then I won't be taking my dork disc/pie plate off the MTB.


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## Gixxerman (21 Jul 2010)

battered said:


> I have better things to do on my bike than worry about what I look like on it, or what other people think. I'll look up the road, not in reflections in shop windows. ;-)


Hear Hear! The voice of reason speaks.


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## Rob3rt (21 Jul 2010)

My bike didnt come with one!


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## Dan B (21 Jul 2010)

Gixxerman said:


> My bike still has it fitted.<br>I have had the bike for just over a year and I have done getting on for 3000 miles in that time, including a 100 miler.


So? Are you the vast majority? I'm sorry if you feel offended.


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## Gixxerman (21 Jul 2010)

coruskate said:


> So? Are you the vast majority?


Never said that I was. Just get fed up of the bike snobs.


coruskate said:


> I'm sorry if you feel offended.


Not in the slightest. I couldn't give a stuff what other people think.


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## colinr (21 Jul 2010)

> My bike didnt come with one!



Yeah, but your bike didn't come with brakes


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## Rob3rt (21 Jul 2010)

Was talking about my CAAD9 Colin


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## ian turner (21 Jul 2010)

Gixxerman said:


> Just get fed up of the bike snobs.


Not so much snobs as immature in the same bracket as those who refer to the "granny ring" and no doubt
a selection of other such comments (bells possibly).
If they're worried about being laughed at then they shouldn't wear anything that wasn't purchased from
JD Sports street wear selection


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## colinr (21 Jul 2010)

I believe the OP asked what it's for and if it's needed, not for a lecture on fashion.
We got to nine pages of arguing about this last time, give or take the occasional drift off topic.


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## youngoldbloke (21 Jul 2010)

colinr said:


> I believe the OP asked what it's for and if it's needed, not for a lecture on fashion.
> We got to nine pages of arguing about this last time, give or take the occasional drift off topic.



Absolutely 
No need to read further than post no.2.


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## xpc316e (21 Jul 2010)

youngoldbloke said:


> Absolutely
> No need to read further than post no.2.



But we all did!


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## MJN (21 Jul 2010)

I didn't...


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## Rip Van (21 Jul 2010)

MJN said:


> I didn't...



+1


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