Replacing a seatpost on a 2001 Raleigh C30
 

My wifes bike has a suspension seat post, unfortunately its broken, the collar around the shock is rotating around and the seat moves back and forth because of it.
anyway, im in the market for a replacement seat post, but i can't make out the measurements on the seatpost, and bike pedia just says its aluminum... any ideas ? trying to avoid the bike shop..

let me know

Does it have a shim on it? If it does, I'd suggest getting a post to fit the frame without the shim (one of my wife's bikes came with a suspension post with a shim and I replaced it with a solid post that fit without the shim). Easiest way is to use a caliper to measure the OD of the post or shim. You can also measure the circumfrance and divide by PI but this is a bit trickier.