Cleaning my 10spd Tiagra cassette on my roadie yesterday noticed the plastic spacings between the fixed larger section of cogs were breaking up and coming out of the cassette.

Had the cassette off and noticed most of the plastic spacing bits are cracked. About 1500 miles on this cassette.

Never seen anything like this before. I do have a theory as to the cause. I may be way off the mark however… The freehub body is showing a few gouges where the cassette is cutting into the body. I wonder if the cassette ‘moving’ into the gouges has caused pressure from the splines onto the plastic bits causing them to break?

It’s a bit wierd as I’ve run Tiagra since I had these wheels with no problem. At the same time I fitted this cassette I changed the freehub body from the original alloy to a steel one as the gouging had got so bad it was impossible to remove the cassette as the gouges on the alloy freehub were so deep.

Will I die if I continue to ride with this cassette 😛 Before anyone suggests running a better quality cassette I did try an Ultegra but that gouged also and I wore it out in 1500 miles during this attritional wet, gritty weather last winter.

Wild guess, but if the locknut was overtightened could the spacers have been cracked?

Is that a dirty big crack on the hub flange?

Is that a dirty big crack on the hub flange?

I didn’t notice that but just gone out to have another look – yep yer right.

ooooofft!

Raaarr. That might explain a few things.