So I've recently purchased a 2006 giant tcr model and I wanted to change out the seat post. The specific model I have came with a carbon post and a rubber shim (to fit in the frame's larger inner diameter) and I was wondering if I need to replace with same diameter post? Or my other option would be to remove the rubber shim/gasket and measure out the inner diameter of the frame's seat post. Any takes or experiences on this?

I used to run a 2005 Giant TCR and that was a round post and there was no shim/gasket between the post and the frame. I do not remember any changes in model year between 05 and 06. Sounds like that is a shim that was added to make up for the incorrect size post being used.

I can't answer the question, but wonder if the rubber shim might be to prevent dissimilar materials from developing corrosion caused by electrolysis. IIRC there were both aluminum and CF versions of the 2006 TCR. OP, is your frame aluminum? BikePedia says the 2006 TCR 1 has a TIG-welded ALUXX SL aluminum frame and a carbon seatpost

2006 Giant TCR 1 | BikePedia

Appreciate all the responses guys and sorry for any delays.

What was the seat post diameter you were using if you even remember since it's been awhile. The current model I have has a carbon post with that rubber shim. I really have crank down on the seat post screws and it makes me a little worried that I might strip the threads from over tightening. I'll have to remove the seat post and measure out the inner diameter without the shim to see if I can get an appropriately sized version.


That is my exact bike. I wanted to get a thomson seat post but wasn't sure if should get it in the same size as the carbon seat post or measure out the inner diameter of where the seat post enters.