Crank brothers Cobalt 2 setapost problems

[Johno]

Hi hubbers i recently purchased a Cobalt 2 seatpost. My problem is that there is too much play between the seatpost clamps and the seat rails. I have tried tape but that works lose. My next train of thought is to try and make up a shim to fit around seat rails. Any ideas that might help as i know this is a problem with these seatpost (found out post purchase). Thanks

[Robbow]

I have the Cobalt 3 post, and the simple answer is tight, VERY tight and then it wont move.

[JanJan]

The problem lies within the machined rail spacer. I have used various Cobalt Seatposts and the newer ones are worse. The newer seatposts's (all the stock that Bicciletta sold) spacers were machined to a 9mm rail and sold as a 7mm saddle unit. Tightening the clamp over 8Nm could cause the threading to seize, seeing that it is stainless sleel.

 

I rolled hard plastic around my rails, then tightened them. No problems thus far.

[Johno]

Yes i was thinking either a hard foil, hard plastic or coke tin. Thanks for advice

[GreatGusto]

I've added aluminium tubing to a seat rail on my daughter's bike because the rails were too thin for the seatpost clamp. Buy aluminium tubing at your hobby shop (maybe even Builders?). Cheap. Cut a length and then slit it down one side. Pry it open just enough to get it around the seat rail and pinch it closed again. Install as normal.

 

If you don't buy aluminium tubing, Coke tin is the next safest bet, wrapped around 4 or 5 times. Plastic is nowhere near as good.

[Johno]

Exellent thanks will try it out