cassette biting into hub
 

took off my cassette today and found that it had pushed grooves into the hub.
anybody know what causes this?

Generally, individual steel cogs vs. a softer aluminum freehub body.

are freehub bodies generally aluminium and not steel? i have a shimano wheel.

Looks like steel cogs vs. aluminum freehub. My question is why would someone make a freehub out of aluminum? Weight weenieism extends that far?

I suspect that it's more of a manufacturing cost issue. Aluminum can be machined faster and with less tool wear.

In guessing being able to advertise lighter weight with little to no extra cost for the manufacturer. Aluminum freehub bodies should be shunned on anything with shallow splines but manufacturers want compatibility and light weight. The Sram red cassettes work pretty well on aluminum shallow-splined freehubs due to their single "carrier" on the 7 largest cogs.

Your pictures show normal wear for an aluminum freehub body. Don't worry about it.

As for what causes it.... the torque from your legs. :)

It's caused by failure to follow directions.

Check out the torque spec that's engraved on the lockring. 40 nm = 30 lb/ft. That's a good amount. Imagine a 30 lb weight hanging off the end of a foot long wrench. It's certainly more than I would use if I were depending on my own judgement. If you tighten your cassette that amount, it will lock all of the cogs together so that individual cogs can't bite into the freehub body.

To be honest, every time I torqued a lockring to the spec'd amount it came loose a couple hundred miles later. I now use the "torque until it feels right" method.

And 30 lb-ft is not much at all.

I'm finding that hard to believe. 30 lb/ft is bottom bracket and crank arm torque. Those are, by a good margin, the tightest fasteners on a bicycle.

What you need are the AmericanClassic inserts (Thanks WR!)

http://www.bikeforums.net/archive/in.../t-269650.html
105 10-Speed (http://www.amclassic.com/pdfs/web10_Speed105.pdf)
Ultegra 10-Speed Clips (http://www.amclassic.com/pdfs/web10_SpeedUltegra.pdf)
Dura-Ace 10-Speed Clips (http://www.amclassic.com/pdfs/web10_SpeedDuraAce.pdf)

'Tis your fearsome wattage. Apparently no big deal for the wear shown in your pictures, keep on working on those grooves.

30 lb-ft = 350 inch pounds. It's a lot.

Incorrect.

Correct.

Correct.

I wouldn't call it a lot. It might be "a lot" to someone who only works on bikes, but it's not really a lot as an overall fastener torque. On my lockrings I use a 12" crescent wrench. 30lbs isn't very much force for me to put on, I don't have a torque wrench with me, but I can guarantee from feel that I'm putting much closer to 60 ft lbs on there, never had a problem overtightening them.

As everyone else has said, that's a Shimano cassette and an aluminum freehub body. Campy cassettes don't do it, and SRAM cassettes don't do it much, because of the way they're designed.

If you want to run Shimano cassettes on an aluminum freehub body, get the American Classic clips mentioned above. You'll have to call American Classic (unless it has changed), they aren't listed for sale anywhere.


And by the way, 30*12 isn't 350. Just thought you should know.

Approx. :rolleyes:

I should mention. i only have ~2000miles on that wheel. should it really look like that?
if thats normal wear, then I would have to replace the wheel after like 10k miles?

If SRAM doesnt do it...then cheaper to buy the SRAM now before the hub is ruined?

A) yes, that looks about normal. I've seen much worse, but from big sprinters.

B) you wouldn't have to replace the wheel, just the freehub body

C) either get a SRAM cassette, or get the American Classic clips (much cheaper).

do people take off the cassette much? what for?

i'm wondering if there is some sort of maintenance i'm missing.

This freehub body had a Campagnolo centaur cassette on it. The 25t through 21t cogs pinned together as a unit.

http://i149.photobucket.com/albums/s...100_3315-1.jpg

Dude, relax. These notches are nothing to worry about - until they get really deep (greater than half the width of the spline or so), they won't affect how your bike works. If this is the most problematic thing in your life I envy you! :p

I meant they don't do it as badly, and it doesn't affect anything. There's so much material there, much better design the way it interlocks.

Yep, this is an annoying weight weenie-ism. I just weighed an aluminium body and an oldish 9sp steel Shimano one, and the difference is a measly 43g!

The cogs can eventually be very hard to get off, which is obviously a drag if ya wanna change wheels regularly.

Campag is a better design for this. Unfortunately, Shimano designed their bodies way before alu was common for this use, so it's not a good design for a soft metal.

Also, the threads for the lockring are a lot easier to strip.

Note that the SRAM freehub bodies don't work with DA cassettes.

in this case, i removed it because a spoke broke and i figured it was easier to work on the spoke with the cassette off.
other than that, cleaning with mineral spirits or swapping to another wheel are 2 things I can think of.