Carbon seat post - safe to use a shim?

[alex1981]

Hello...just a quickie...I have been on the lookout for an Alien Cyclops seatpost as I liked the last one that I had...finally found and bought one...but it is a 25.0mm and my frame is 26.8mm.

Is it safe to use a shim? I know it is fairly normal to use an alloy shim on an alloy post, but is there any issues with using an alloy shim on a carbon post? Or any other bits of advise?

Cheers


Alex

 

[feetabix]

a shim will work but will put lots of stress on a smaller amount of frame/seatpin.......dependant on your weight i would advise against it,i have within the last week hastily removed a shimmed use post from my klein having found a hairline crack starting near the clamp....just be carefull!!!!!.....then again you may not be fat like me!!

 

[alex1981]

Im not that heavy...11.5 stone...depends how fat you class as fat I guess hehe!

I also don't have much seatpost poking out about 140mm so I am hoping that will work in my favour! (argueably I should have gone for a 17" instead of a 19" frame buy hey ho)

 

[MJN]

I ran a carbon USE post with shim for 5yrs with no probs,it'll be fine.

 

[alex1981]

Nice one, thanks MJN, good to hear it from someone that has actually used one personally Was it jsut a standard alloy shim you used? I have ordered a USE one so should be fairly decent quality

p.s found by far the cheapest place to buy shims is this place: www.dotbike.com - a wide range and cheapest as they do not charge any delivery

 

[MJN]

I used the alloy shim USE supplied with the post taking the 25.0mm post to 27.2mm.Use grease on the outside of the shim but either put the post in dry or use anti slip compound,never grease a carbon post and make sure not to over tighten the seat collar,if you hear a cracking noise its too late :shock:

 

[alex1981]

Nice one, thanks again

 

[tintin40]

No problem. I use a USE 25 with a 26.8

 

[alex1981]

Nice nice, all reasuring stuff Happy now, finally got the seatpost for my build...just need to make a decision on the chainset and bb