bloody annoyed.

just been building up the 5-pot for the wife.

i ordered a ks i7 supernatural post from actionsports.de in a 27.2mm diameter to fit (early generation 5-spot so 27.2mm diamter)

does it fit?… does it hell!

i have a 27.2mm carbon post which slips straight in.

not sure what to do now… there are some marks of fitment at the very base of the post, but i reckon i have good cause to return it for a refund… very annoying though, as i wanted a dropper post on there for her.

are you sure the frame is not a bit crimped from the carbon post being a bit undersized?

First thing to do is use/borrow some calipers to measure the seatpost and frame.

as above re: wear/crimping

Assumibng you have backed off the tension from the seatpost clamp/collar (including the wheel/allen key bolt on a quick release lever type)

try inserting the KS post into the frame but with the seatclamp removed from the frame. If it’ll go try with the loosened off seatclamp around the KS post, put the KS post into the frame first and then slide the seatclamp onto the frame second.

Unless the carbon post has partially delaminated and there is a layer stuck to the inside of the frame or something?

Calipers would be a good idea

Calipers will tell you. We had issues with a seatpost for the wifes Santa Cruz. Best fitting one in the shop ( we tried a few !!) was the X Lite post of many moons ago.

Do what is suggested above as far as measuring the diameter with calipers and the seatpost clamp. If the inside of the seat tube is rough, scored, or slightly undersized, then get a brake cylinder hone at an auto parts store. Chuck it in a drill and hone the seat tube. The stones aren’t coarse enough to remove much material, but can help a lot.

I just bought a new (to me) frame that takes a 27.2 post but it would only go in a couple of inches. There was a thin layer of gunge, possibly a mix of grease and dirt. I cleaned it with a rag on a stick and now the post slides in smoothly. Didn’t take much to go from no fit to nice fit.

If your frame is under sized by a Thomson post…