Gladius

Was changing the cassette on my wheel last night. Simple enough, I have a chain whip and a torque wrench. I get the top 7 gears off, but the bottom 3 (which are fixed together) will not come off - they were stuck to the freehub. Weird. So I use a little elbow grease and they pop off - along with the freehub cylinder. (Note that I am not a mechanic and don't know the names of the parts...)

The freehub cylinder went flying, as did the cap on the top of it, as did two gear-like cylinders inside it. I have no idea how this is supposed to go together, so I will probably just take it to a shop to fix (or replace?) unless you all tell me it's a piece of cake to fix. I have no idea which orientation the two gears go in, or why the thing came apart (I would expect it to be screwed on or affixed in some way).

The other thing I noticed is that the "splines" on the freehub cylinder have little indentations where the inner cassette splines bit into it - this is undoubtedly why the cassette was stuck to the hub - and wondering why that would have happened. Is this common? Was the cassette over-torqued? Did I just hit 4000W?

hueyhoolihan

it's probably toast. the prying (if any) may have weakened it. no matter... aftermarket Shimano (if that's what it is) freehubs can be inexpensive and readily attached with a large hex head socket. you might want to look into that.

woodcraft

It's common for the cassette splines to dig in to the freehub. This is not related to how tight the cassette lockring is.

Good chance that the LBS can put it all back together.

gsa103

What cassette? That's the main reason that lowest cogs are usually bonded together, to provide a larger area to distribute loads. Its basically an issue of Aluminum hub shell & steel cassette. High torque loads, such as standing on the pedals at low RPM make it worse. Dura-Ace hubs now use titanium shells to prevent that while being weight-weenie.

Gladius

It's a 10-speed Shimano 105 cassette on whatever freehub comes on the Bontrager Aeolus wheel.

SlowJoeCrow

A Shimano 105 cassette should have an aluminum spider on the 3 lowest cogs, which might gall and stick to the freehub body. The higher end Bontrager wheels use DT Swiss hubs and your description of what happened and what fell out closely resembles a DT Swiss 240 hub disassembly sequence so you could try a DT Swiss manual for reassembly instructions.

hueyhoolihan

this is probably what you need, if you destroyed the freehub (as i read your OP to indicate). wiggle.com | Shimano Ultegra 6700 10 Speed Freehub Body | Hub Spares

you'll need 10mm hex wrench, most likely, to remove what's left of the old one and install the new one.

BTW, you should be able to get one for less than the one on Wiggle.

fietsbob

Down side of superlight parts ... mid range cassette drivers are steel . yes, now, most cassettes cluster the larger cogs in a single unit .