Bicycle Mechanics - cassette alignment pin

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derath
10-10-06, 06:57 PM
Well that is what I am calling it. I am still getting used to this newfangled rear cassette thing. My other bikes are old.

Anyhow, I took off my rear cassette (cog?) to soak it as well as my chaing. As I was scrubbing it (it is an SRAM) I noticed I could spin the individual cogs around a threaded pin that basically held it all together. Well I spun the smallest one too many times and it came off. I managed to get it back together and then slid it back onto the hub.

But it got me to thinking. Does it really need that pin? If I took it out (and therefore had each cog and spacer loose) could I just put it back on the hub one at a time and then put the lockring on and be done with it? Having them loose would certainly make cleaning them easier. Of course I could see losing one of those spacers easier if it was all loose.

-D

ISeeDeadHuffies
10-10-06, 06:59 PM
Yes. The pin is unnecesary
moxfyre
10-10-06, 07:02 PM
Yep, pins not necessary. You can remove them and take your cassette apart if you want to change an individual cog or something. However, it's often a good idea to KEEP the pins, because they hold the cassette together which causes the force on individual cogs to be spread out over a larger area. With loose cogs, it's possible for the forces of pedaling to wear notches into the freehub body. With the cassette held together with pins, this is less likely to happen.

Skipper
10-10-06, 08:06 PM
The pin is not needed. It just keeps things in a nice little bundle when you take it off the hub. Judging from the diameter of the pin, it probably does not prevent anything other than scattered parts.
HillRider
10-10-06, 08:12 PM
If there is a single pin the cogs can rotate around, the pin has no benefit except simplicity of installation.

Shimano and Campy cassettes are bolted or rivited together with three "pins" except for the smallest one to three cogs. The fact that the large cogs are not free to rotate individually distributes the drive torque over a longer section of the freehub splines and reduces the load on any one point. This is not a big deal with steel freehub bodies but is a good thing for Ti bodies (9-speed Dura Ace) and really necessary for Al bodies (new 10-speed Dura Ace and almost all Campy bodies).