Sunday, April 27, 2008

In praise of pie plates

I agree with the Bike Snob that pie plates are about as misplaced on many bikes as the red skinsuit man, but they do have their utility.

19th Century Technology

Pie plates are plastic rings placed against the spokes on the rear wheel of dérailleur equipped bicycles. They protect the wheel and derailleur against damage by preventing the chain or dérailleur from going into the spokes if the rear dérailleur is misadjusted. I once had to replace spokes, chain, derailleur and chainring for want of a spoke protector because my dérailleur hanger got bent in on the train.

If you ride a high end road bike, you're expected to fiddle with the limit screws like a tweaking meth user, so get rid of the pie plate. Ditto for fixed gears, singlespeeds and hub geared bikes, which have no need for spoke protectors. If you ride your bike for transportation, though, and your bike is flung against other bikes, crammed into closets, dropped on the sidewalk and you otherwise don't want to mess with the gear adjustments, keep that spoke protector in place.


ark said...

No! :)

SiouxGeonz said...

Snork... I think my pie plate on the fast hybrid got brittle and flaked off after 10,000 miles or so ;) we'll see how long hte one on the Dahon lasts!
But hey, I'm allowed to have one since I'm on a hybrid and a proud Fredwina :)

Guitar Ted said...

Just to let you know, these are most commonly referred to as "Cosmic Ray Deflectors" by a lot of wrenches. Owing to their redundancy if your set screws are properly adjusted.

Also, I find that most "CRD"'s are rather flimsy, too small, or so brittle that they are practically useless on the majority of rigs that come through our shop. So if you must use one, please have it properly sized or replaced as necessary. Otherwise the "phred factor" goes through the roof with these odd pieces of cycling gear.

Nathan said...

Yeah, that's one thing that BSNYC didn't address... was the faintest utility of them. I think they are one of the ugliest things on the bike, but if it ever saves me from a long walk home or unecessary repairs...

Sweet William said...

I have nice little bite marks in my spokes - the side effect of travelling by ferry where the crew man-handle everyone's bikes.

Even in the usual rounds of commuting and shopping my bike gets regularly dropped, bumped and thumped. And (usually) not by me!

I'd buy a Rohloff but the mortgage comes first.

Fritz said...

Ark: Yes! :-)

We all know Sue's about as Fred as they come.

G-Ted: I completely forgot to mention my 10 year old mountain bike, which is still equipped with its pie plate!

Nathan: Agreed. They *are* ugly, though there are after market spoke protectors available that aren't quite so obtrusive.

Will: Been there.

Ron Georg said...


A while back in Mountain Bike (I believe) published a reader's question on this topic. The reader wanted to know how to get a spoke protector, and what type to buy. The writer suggested he should march into his bike shop and insist on a Big Wedgie, that the shop would know exactly what he meant, and he'd get what he deserved.

I wouldn't suggest Fritz needs his undies snugged, but I don't see too much utility to the devices. If your hanger is bent during a ride, straigten it if you can, or use the inner limit screw to keep the derailleur out of the spokes. At the very least, avoid shifting that far in.

If you're unlucky, and you don't discover the problem until the overshift occurs, a spoke protector isn't much help, especially since the lower part of the derailleur cage can still get into the spokes.

I've untangled many of these messes over the years (even on one of my own bikes a couple of decades ago), and I've never had cause to say, "Phew, good thing you had that spoke protector."
Happy Trails,

295bus said...

So *that's* what they're for.

I think I finally got rid of mine during my mast major bike repair job--putting on a new derailleur, after the previous one got jammed in the spokes, no thanks to the "protector".

bikesgonewild said...'s almost like you NEED a degree in fredology to run your chain into yer spokes... my question is "where does all that pie go anyway ???"...

Jared said...

Hehe...a meth user wouldn't tweak with hi and lo adjustment, he or she would make a derailleur with a spare roll of wire, some aluminum cans, and a few spare mechanical pencils.

Anonymous said...

I always thought they were called Dork Disks? =)

Anonymous said...

Wish I would have had one a couple weeks ago. Threw my chain off of the largest cog, into the spokes, pulled the derailer in and wrapped it up and around. $170 later I had to replace the hanger, derailer, 3 spokes and the chain.

cafiend said...

Sounds like the helmet debate has moved to a different part of the rider/bike combo.