Cassette biting into aluminium freehub body

[Marchrider]

That's an interesting idea, but I definitely can't do that with my Campagnolo cassettes because the spline pattern is not symmetrical.

I have an old rear wheel with a Shimano freehub, and some Shimano sprockets. I will check them... Hmm, same problem - the sprockets only seem to go on one way round!

you have to file a little off, (7 & 8 speed) and I have always found they work OK, if you have just put a new chain on and it is slipping in one gear, then this mod will save a new cassette until the next chain.

this bit

 

[Marchrider]

Fair enough.

IIRC only the smallest two sprockets are free on a 9 speed, the rest riveted. I'd be amazed if the friction from torquing down the locknut is more effective at that than the rivets though.

I would imagine most of the time that is true, they will be riveted on a machine to a set pressure, but if damage starts to occur as per the OP, then may be they have worked loose or were never done properly. And they aren't (or have always) been riveted, they used to be held together with three long M4 bolts

But for me that is what is happening on the OP, all the driving force is going through one sprocket rather than through the whole cassette

 

[almostvegancyclist]

I imagine that when not fully tight the sprocket you are driving will be delivering most of the energy to the freehub, when fully tight that energy is shared by the rest of the cassette.

I noticed this primarily because I disassemble my cassettes so as to reverse worn sprockets. and without those rivets holding it together the mess of the freehub is notable - fully tightening it to 45nm stops this.
although the rivets holding the casstte together seem tight, I imaging there will still be movement

I see your logic there. Actually I noticed the damage as I was tightening the lockring, before riding the wheel at all. It looks like the smallest (11t) cog is digging into the end of the splines as I tighten the lockring.

 

[twentysix by twentyfive]

riveted

I've had the rivets loosen so that the sprockets can move individually to some extent. Enough movement for the notches to appear as described. I also modify cassettes by changing the sprockets to what I prefer. In cases where rivets are employed I drill them out (soft metal generally). Fortunately I've only ever used steel freehub bodies. I shall be avoiding aluminium ones for sure.

 

[the_mikey]

Why would that make a difference? Surely the splines take the load, regardless of locknut torque?

I'm in agreement, imagine a freehub without splines, secured only by the torque of the locknut, this would be a recipe for trouble.

 

[wafter]

Why would that make a difference? Surely the splines take the load, regardless of locknut torque?

The larger sprockets are held together by bolts / rivets, so the load applied to one is transferred to them all and reacted by their collective contact area with the splines on the freehub.

It seems reasonable to assume that if the locknut is tightened down sufficiently, load applied to the smallest sprocket would be reacted (at least partially) by its interface with the rest of the cassette - this load being spread across their collective contact area with the splines and lessening the amount of load carried by the interface between the single small sprocket and the splines.

We can see the benefit of sharing the load across multiple sprockets by the marks on the hub pictured - despite the fact the larger sprockets exert more torque on the hub for a given chain tension, they've still caused less damage than the one smaller sprocket.


Pretty disgusted that this is considered normal - IMO this is not an acceptable outcome and either the design or material needs to change to prevent this. Of course steel would be fine, were it not for the previous weight-saving demanded by the marketing department..

 

[silva]

Just another topic that makes a fixed cog rider happy.

 

[Keezx]

A proper design (Campagnolo...) of the freehub prevents exessive biting , you don't need to ride with just one cog.