Alasdair

The last few times I have taken my cassette off of my FSA RD420 wheel for cleaning, I found the individual cogs have cut about 1 mm into the splines of the hub and requires a bit of convincing to be removed. Is this a "bad thing" that requires my hub to be replaced or just expected behavior?

Retro Grouch 

The torque spec for the lockring that holds the cassette onto the freehub body is about 30 ft/lbs. That's quite a bit - way more than I'd ever use if left to my own judgement. Using that much torque squeezes all of the cassette cogs together so they don't cut individually into the freehub splines as much.

jimc101

This happens with Aluminum freehubs, not ideal, but it generally can't be avoided.

If you look at Shimano freehubs, non currently available are made from Alu, they are all Steel up to the Ultegra/XT level, which isn't affected by the cassette digging in, Novatec offer their ABG to avoid this as well. Cassette choice does make a difference, but all will have an effect on standard Alu freehubs to some extent.

FBinNY 

To an extent it's par for the course. Various factors make it worse or better.

As noted above, steel freehub bodies are tougher, and tightening the lockring properly reduces some of the issues.

IME, the most significant factor is whether the larger sprockets are on spiders which spread the load, vs. present a 2" wide face to the freehub.

Then there's the size of the larger sprockets, the weight and strength of the rider, and the steepness of the hills. I wouldn't expect much of an issue in the plains states, but large rider in central Pennsylvania is going to be harder on his freehub no matter what.

Andrew R Stewart 

The cassette design also influences this cog tab digging into the freehub splines. IMO the lockring clamping pressure won't prevent the pedaling forces from acting on the splines. So a cassette with individual cogs will have the stress acting on a smaller point of the spline then a cassette with a "carrier" type of cog assembly. This is why some freehubs spec a "carrier" type of cassette assembly, the manufacturer understands that notching will happen otherwise. Andy.

dsbrantjr

This is to be expected as stated earlier. The best you can do is to clean up the burrs with a file to ease installation/removal and torque the lockring properly, 22-36 ft-lb is the Shimano spec.

fietsbob

Its part of why there are so many cogs combined in a sub assembly with one wider interface with the splines on the hub-driver.

achoo

Nah, the best you can do is buy wheels/hubs with steel or TI freehubs and not worry about it at all.

Alasdair

Thanks All! I will ensure that the lock ring is torqued appropriately and maybe look at a steel freehub for future.

FastJake

Aluminum is not an appropriate freehub material unless the splines are taller like on the orphan Dura Ace 7800 hubs. Otherwise, aluminum is not hard enough and the cogs will dig in. It's nothing more than a poor design choice intended to save weight.

Solution: buy some wheels with genuine quality Shimano hubs.

HillRider

Campy also uses an aluminum freehub body and, like Shimano did with the 7800 hubs, makes the splines taller and the matching grooves in the cogs deeper. They may also use a harder aluminum alloy than some manufacturers. I have well over 30,000 miles on a pair of 10-speed Campy Chorus hubs used mostly with Veloce-level cassettes (all loose cogs, no spiders) and they are still in excellent condition and the cassettes remove and install freely.

FBinNY 

This is an unfair general indictment. There are a number of variables: rider strength and weight, terrain, size of larger sprockets, and whether larger sprockets are on aluminum carriers. Logic says, that if aluminum is OK for the carrier, it's equally OK for the freehub body. So while an aluminum freehub may be damaged by a heavy rider using loose sprocket 12-32 cassette in Pennsylvania or the Dells, it may hold up fine for many other people and conditions.

IMO- the real culprits aren't aluminum freehub bodies, but large cassettes with all loose sprockets.