Plastic disc? Whats this for?

[SunBurnt]

I have a new Trek bike. There is a clear plastic disc (shaped almost like a CD-ROM disc ) located on my rear wheel that is clipped onto some spokes, and this disc is placed between the biggest (25 teeth) cog/sprocket and the centre of of the wheel where the spokes meet.

It doesn't appear to have much of a function to me, coz if I unclip the disc off the spokes, it moves freely, it's not as if it's there as a spacer or something.

So... what the heck is it for??

 

[MattLarson]

I have a new Trek bike. There is a clear plastic disc (shaped almost like a CD-ROM disc ) located on my rear wheel that is clipped onto some spokes, and this disc is placed between the biggest (25 teeth) cog/sprocket and the centre of of the wheel where the spokes meet.

It doesn't appear to have much of a function to me, coz if I unclip the disc off the spokes, it moves freely, it's not as if it's there as a spacer or something.

So... what the heck is it for??

It is there so if your chain slips off the large cog, it does not tear up the spokes (hopefully).

Matt

 

[SunBurnt]

It is there so if your chain slips off the large cog, it does not tear up the spokes (hopefully).

Matt

But I had never seen riders with that disc on their bikes.
Does yours have one installed?

 

[MattLarson]

But I had never seen riders with that disc on their bikes.
Does yours have one installed?

My first bike, a Trek 820, did. My Giant does not.

Matt

 

[meehs]

But I had never seen riders with that disc on their bikes.
Does yours have one installed?

Probably because almost everyone takes them off. It's a "cover your ass" measure by the manufacturers that's probably required by their lawyers.

 

[little_chicken]

did your bike also come with 2 little wheels on the side and a hockey card in the spokes ...

 

[boudreaux]

did your bike also come with 2 little wheels on the side and a hockey card in the spokes ...

oooohh, and yours has pink sparklie handlebar streamers too?

 

[little_chicken]

oooohh, and yours has pink sparklie handlebar streamers too?

yep .. and a banana seat, high handlebars and a stand .. sorry for the smart ass comment .. I was just in the mood ..

Cheers

 

[dazed&confused]

did your bike also come with 2 little wheels on the side and a hockey card in the spokes ...

In Texas the card is a football or baseball card. Only the year Dallas Stars won the Stanley Cup did hockey cards become an option...

 

[puma]

Probably because almost everyone takes them off. It's a "cover your ass" measure by the manufacturers that's probably required by their lawyers.

The cover is like reflectors that are put on spokes. You will usually see these things on the "less-elite" bikes, I assume you're Trek isn't the same model that the USPS boys use. Also, if the rear derailler is setup properly, then the chain should never fall off into the spokes.

 

[kenright]

You will usually see these things on the "less-elite" bikes, I assume you're Trek isn't the same model that the USPS boys use.

My local shop had a new 5.2 Madone and it had one on the rear wheel. I mean come on, if you're going to drop $3000 on a bike, you better know how to ride it and adjust it without dumping your RD into your wheel

Maybe I take some things for granted.... Like everyone has a right to have a driver's license ( JK )

 

[SpearSlinger1]

So... what the heck is it for??

On my bikes, it's for snapping off with a hammer and screwdriver.

 

[wyllisx2]

The one on my 8 year old's bike broke a clip & spun freely. It didn't bother him but it did me when we went out on 10 mile charity ride. The tick tick ticking drove me crazy for an hour & a half. After I removed it the 3 minutes of pleasure I had pounding it to itty bitty pieces with a hammer almost made up for the 1.5 hours.

 

[RC2]

It's a frizbee for those long rides with a friend and need a break/diversion.

 

[SunBurnt]

On my bikes, it's for snapping off with a hammer and screwdriver.

Is breaking it the only way to take out the disc?

 

[ATM]

The cover is like reflectors that are put on spokes. You will usually see these things on the "less-elite" bikes, I assume you're Trek isn't the same model that the USPS boys use. Also, if the rear derailler is setup properly, then the chain should never fall off into the spokes.

Are there any legal requirements to have reflectors on your spokes or elsewhere while riding on public roads?

 

[SunBurnt]

Are there any legal requirements to have reflectors on your spokes or elsewhere while riding on public roads?

Here, I don't think so.
But its you own life we are talking, so for safety sake, get something to tell drivers you're are on the road.

I bought myself a cateye 5 LED blinker for my rear. I turn it on even during the day.

 

[serenaslu]

Are there any legal requirements to have reflectors on your spokes or elsewhere while riding on public roads?

In the U.S. the laws vary in details from state to state (I suspect their are some screwy local ordinances as well). It seems almost universal that front and rear reflectors visible for a finite distance range (600-100 feet seems common) are required usually from 1/2 hour after sunset to 1/2 before sunrise, but some just say at night . Some states require either pedal reflectors or side reflectors at right angles as well.

Some have more specific requirements for what new bicycles must be equipped with from the dealer. (e.g. New York: Every new bicycle shall be equipped with reflective tires or, alternately, a reflex reflector mounted on the spokes of each wheel, said tires and reflectors to be of types approved by the commissioner. The reflex reflector mounted on the front wheel shall be colorless or amber, and the reflex reflector mounted on the rear wheel shall be colorless or red. )

Of course it doesn't say that the owner can't remove them before he even gets out the door.

Many states also require your to have a bell or other audible signal on all bikes at all times they are on public roads. I, however, probably see more safety flags (and that's not very often except for recumbents) than I do bells, these days.

 

[SpearSlinger1]

Is breaking it the only way to take out the disc?

It's more trouble, but on the ones I've really looked at you could get to by taking off the cassette. More trouble than I want to go through for something I'm just going to throw away.

 

[SunBurnt]

(e.g. New York: Every new bicycle shall be equipped with reflective tires or, alternately

REFLECTIVE TIRES!!!
Thats one I have never seen before.. any web links to that?