freedomrider1

Getting a new bike in a few days and it has a big plastic thing on the back wheel.This keeps the chain from going into the spokes. The bike i ride now has a clear smaller one,barely noticeable that i got to see work on a ride in October.My chain jumped the last gear and that plastic thing stopped it.What to do?

Bikey Mikey

There are cyclists who remove them--some that scoff at those who keep them on. I don't care what others think; I'm keeping it on. The plastic guard keeps the chain from going into the spokes, but, more importantly IMHO, it keeps a spoke from going into the chain. A spoke going into the chain could result in a very bad crash.

freedomrider1

Wow,did not think of that one. good call.

Bob Ross

I've long contended that if you don't know how to remove the "plastic thing" without destroying it, you should leave it on...but I realize that's a pretty snarky attitude.

More importantly, it sounds like you (OP) need to leave it on, at least until you've had a chance to take your bike to an experienced mechanic for a rear derailleur adjustment, because right now that plastic thing is doing its job.

Siu Blue Wind

My mountain bikes have them on (crash factor), my vintage does (age appropriate), the cruiser does (lazy), and my hybrids and road bike do not. I try my best to keep the roadie and the hybiuds tuned to a T and it's not like they are bouncing around like the mtbs are.

Bikey Mikey

Even tuned bikes can have a spoke break at the hub and get into the chain and gearing. It's a risk I'm not willing to take, but I won't say anything against or about a cyclist that does remove it--his/her choice and business. I'm just saying this so that the OP understands that even a well tuned bike can be at risk.

Siu Blue Wind

Your point is very valid!! I agree wholeheartedly. I'd rather have them on mine because to me, it would be much safer. I never took them off of my bikes, they didn't come with any. Plus I was thinking of chain falling into the spokes rather than the other way around. But yes, you are right.

freedomrider1

Brand new bike still at shop,he will remove at my request.

howsteepisit

How would a (broken?) spoke go into the chain and cause a crash? It will not lock the wheel or anything else, except at the worst, you could not pedal. Back in the day, I broke many a spoke, never caused a crash at all. to the OP, for now you should leave it on as protection against the chain dropping into the spokes due to an over-shift. This could be caused by two things primarily. Over time a rear deraillier may come out of adjustment as the high limit screw backs out, or much more likely, a minor spill or bike falling onto the drive side may slightly bend the hanger causing a maladjustment. Until sucj time as you are able to assess and adjust the deraillier, leave it alone.

Cleave

Hi, if you keep your rear derailleur properly adjusted then you don't need the spoke guard. I never thought about a broken rear spoke getting caught in the drivetrain and I suppose it happen could but in 40 years of racing and a few hundred thousand miles of riding, I've never had a broken rear spoke get caught and I've never seen that happen to anyone else. My hypothesis is that the probability of that kind of catastrophic failure is very very low.

Wil Davis

I understand your point, but I'm curious to know how many times you've come across the phenomenon, either personally or 2nd hand.
- Wil

Looigi

They are very good sensible things along with wheel reflectors in the spokes. I immediately remove both from any new bike.

Mr. Beanz

New bike, I'd leave it on thru the breakin period giving the cables a chance to settle and to avoid nulling the warranty. Even a well tuned machine by a well tuned mechanic at the time of purchase can go out of adjustment before the cables settle.

Bikey Mikey

I've never had a spoke go into wheel cassette/chain/derailleur, but I did have one break at the hub(old comfort) and who knows what would've occurred had the guard not been there.

There was a post I remember reading where the spoke broke off and went into the chain and destroyed the derailleur. I did a search and this is what I found(see below) but I know I've read it in a post more recent than what I found...or my recall is slipping. I'm not saying this is common...I would think that it is a very, very rare occurrence. More likely it would be the chain going into the spokes. I'm just saying that I see nothing wrong with someone leaving it on and I certainly, if it were my choice to remove the plastic ring, think anything less of the cyclist who kept it on--I certainly wouldn't say or criticize him or her for leaving of the guard on the wheel.

https://www.bikeforums.net/showthread...=1#post2892895

mprelaw

If you're not in your granny gear, wouldn't that cog keep a broken spoke from slipping any farther down into the cassette?

stapfam

None of my Road wheels have ever had them on except that a set of Mavic wheels I bought had one supplied in the box. I fitted in and then found the Cassette would not locate properly. MTB's and I left them on the wheels till I made certain that the RD was adjusted properly and then next cassette removal and I took it off.

Gerryattrick

If they're on when I get a bike they stay on. If they're not they stay off.

Simple

gcottay

And you are not alone. Even these years past early adolescence the dork disk still clashes with my favorite race team jerseys.

Dudelsack 

One vote for leaving them on.

One vote for leaving the reflectors on.

One vote for not filing down the lawyer lips.

Sadly, when I was young(ER) and stupid I did two out of three. I dropped a chain into my back wheel. I have no idea how it happened. I never cleaned up the brown spot I deposited on the pavement at the time.

Altbark

Cable stretch has nothing to do with whether the chain will run off the casstte either high or low. The OP should be good to go once the high and low stops are properly set. Cable stretching causes indexing problems.

I take the spoke guards off my bikes when I pull the cassette to do maintenance. I've found that the plastic tends to get quite brittle after a couple of seasons in the sun and tends to break. Al

Cleave

I agree wholeheartedly. However, for myself, I have a reputation to maintain.

As a beginner, leave the spoke guard on. If you're mechanically inclined, learn how to maintain your bike and eventually you will probably want to take it off. After all it must weigh a few ounces.

revolator

My derailleur hanger just broke two days ago, and my wheel ended up eating the rear derailleur with chain an all. I think the dork disc would've avoided this, but I would still remove the dork disc anyhow.

GeorgeBMac

I just do a simple equation:

If I take them off, I save about an ounce of weight

If I don't take them off, I could save myself from a nasty problem -- conceivably involving hospitals...

With loaded bags and bottles the bike weighs about 45 pounds...

... Soooo, let me think about this for awhile...

Mr. Beanz

I didn't say anything about high or low. I was thinking more bobbling the chain on the cassette, yeah it will throw the chain during a shift if the rear derailleur is not adjusted properly.

Papa Tom

Why is this even being discussed? The manufacturer put the "plastic thing" there for a reason. Leave it on.