Ask Levi: What Is That Plastic Disc on My Rear Wheel?

Here is a question about a little problem that confounds anyone purchasing a new bicycle…

hi there levi! another newbie question… what’s this black plastic plate at the center rear wheel? what’s its purpose? how can i take it off? thanks again!

Sincerely,
Mr. Pete Plate

Hi Petey,

That plastic piece that looks like a pie plate is a spoke protector, and it is sometimes called a “dork disc” because serious riders always remove those before riding a new bike. Apparently, shaving your legs and dressing in colorful spandex is cool, but a spoke protector makes you a dork! ;)

dork disc spoke protector

The purpose of the spoke protector is to keep the chain from shifting into the spokes and damaging the rear wheel and/or causing you to crash. It is totally unnecessary if the rear derailleur is adjusted properly.

The derailleur would have to be totally out of adjustment to actually shift the chain into the spokes, and if that were to happen, I doubt that thin piece of plastic would help at all. It would probably get torn apart by the chain (which could be good, but it probably won’t save the wheel.)

I suggest removing it. It adds needless weight to your bike, it looks ugly, and it will do more harm than good. While I’ve never seen an accident caused by the plastic spoke protector, I have seen them break. The plastic gets brittle from the weather, and whenever it gets hit, it will crack. If it’s not removed immediately after any damage, sharp plastic pieces could snap off and get stuck in your cassette and jam your chain, or maybe even slice your tire.

(I highly doubt it will break and cause an accident any time soon, but there’s always that slight chance.)

To take it off without risking any damage to your spokes, you will need to remove your cassette, pull the spoke protector off, then reinstall your cassette.

If you need a tutorial for that, check out “How to Replace a Cassette Cluster” or read “How to Replace a Cassette.”

The tools for this job will cost about $25-50 total, though. A bike shop would probably do this for a lower price if you want, or you could use a Dremel or another cutting tool (wire cutters or tin snips, perhaps) to cut it off. But bear in mind, you could damage the wheel if you’re not careful!

I would avoid bending and snapping it, since that could put too much force on your spokes.

So here’s what I would do:

1. See if the shop where you purchased the bicycle would remove the spoke protector for free. (Just keep in mind, they had to install it to avoid breaking the law.)

2. Wait until you need a new cassette and just have the spoke protector removed at that point.

3. Buy the necessary tools for cassette removal, because then you can remove the spoke protector safely, and when you need to replace the cassette or switch wheels, you can do it yourself and save some money in the long run.

4. If it’s really an eye sore, cut that thing off!

Or you could forget about it and go for a ride. The choice is yours!

A Complete Idiot’s Guide to Proper Front Disc Brake Cable Routing

Let me tell you a little story about properly routing the cable for your front disc brake…

disc cable routing stage 1

It all started when I purchased my Specialized Stumpjumper at Landry’s Bicycles. I was replacing a stolen bike in the middle of the NCCA collegiate racing season, which also happened to coincide with the gap between bicycle model years. I was lucky to find a bike that fit that was in stock, but I got one.

And what did I do the day after buying it? Raced it, of course!

With the stress of a stolen bike, college, work, and racing season, I couldn’t be bothered with checking out the bike. Plus, Landry’s is always on the “Top 100 Bicycle Retailers” list and they were a sponsor of our team, so I trusted them.

But that led to a little problem… (more on this later.) The problem was caused by the front brake cable routing, which can be seen in the picture on the left.

See, the brake cable is wrapped tightly behind the fork crown and down the fork leg. I never questioned the cable routing until one day when I realized the cable was eating into the aluminum on the fork crown!

You can see the damage in this picture:

disc cable routing damage

Granted, the fork will still work fine. But if given the choice, I’d rather not have the cable rubbing like that. To fix it, I wrapped cable ties around the cable on the fork crown and the head tube (kind of like makeshift cable guides.) That fixed the problem, but it caused another!

The cable tie around the head tube wouldn’t stay in place, so it ended up scraping all the paint off the head tube!

I wasn’t happy at all so I just said “screw it” and let it go.

disc cable routing done right

Then one miraculous day I found an article at BlueCollarMTB.com about proper front disc cable routing. Then everything made sense!

It turns out the cable was not routed properly in the first place! So with the help of that guide and a little common sense, I re-routed my cable to go in front of the fork and down the inside of the leg.

(See the picture on the right, or the picture below, for an example of the proper routing.)

After that simple switch, my braking performance has improved and I have a feeling my fork legs and cable housing will last a bit longer!

What’s the moral of the story then?

Always double check a new bike to be sure it is setup properly.

disc cable routing done right

Chances are the cable was routed improperly when it left from the Specialized warehouse. And not all bike mechanics will bend over backwards to make sure things are perfect. (Although a bike from a bike shop will at least be put together properly, unlike Wal-Mart bikes.)

So you have to look out for yourself! If something looks wrong, it could be. Check it out, read up on the subject, or take it back to the shop if you have to.

(Of course, you could learn to do your own repairs, too.)

Also, note that the “complete idiot” in this case is me, for assuming that the cable was properly routed to begin with.

Happy trails!

Clicks, Squeaks, Clunks, Rattles, and Other Annoying Noises

Noises from your bike are a true pain in the behind! It’s nearly impossible to diagnose the problem, especially when it only happens sometimes!

Thanks to Jim Langley, we have some help on the topic. Click the link below to check out a new page he added to his site:

http://www.jimlangley.net/wrench/keepitquiet.html

Jim Langley also wrote one of my favorite bike repair books, which you can find at Amazon: