Seatpost shims

[PaMtbRider]

My brother-in-law just bought a Bianchi that has a 31.6 seatpost. He has a carbon 27.2 post that he would like to use. What's the general consensus on using seatpost shims?

[dave thompson]

Seat post shims work fine and solve problems.

[toaster]

Just in case, I have a shim if one is needed. PM me if you are looking for it.

[StellaBlue]

I use on on my 29.4 (not many options at that size) never had an issue. I think the one I have is made by Use?

[Don49]

I'm using one on a Curtlo Advanced Mountaineer so I can run a 27.2mm Thomson post. Zero issues, works perfectly. I think it was this one: http://www.jensonusa.com/store/product/SE405C00-Seatpost+Shim+Fits+272Mm+Seatpost.aspx

[MadRocketSci]

USE plastic (resin) seatpost shim works fine...31.0 here for the peg.

[Cinci Jim]

Two of my Serottas use a 30.9 seat post and a 34.9 front deraileur clamp. When I got the first one it had a 27.2 post with a shim. It worked fine, I just did not like the look of the "stepdown" from the 34.9 seat tube to the 27.2 of the post - it made it look kind of spindly. The hard part is finding 30.9 seat posts. I managed to score a Ritchey Carbon SuperLogic a while back that looks great on the HSG.

[Rada]

I used a shim on a 25.4 Thomson to fit a 26.8 seatpost. No problems, although I think I read somewhere that Thomson does recommend shims.

[vqdriver]

They work fine. Similar to stella I had little choice when my frame took a whacked out 27.4 post.

Only caveat I think would be aesthetics since 27.2 to 31.6 is a sizable jump. The skinny post may not look right with a thicker ST.

[oldpotatoe]

My brother-in-law just bought a Bianchi that has a 31.6 seatpost. He has a carbon 27.2 post that he would like to use. What's the general consensus on using seatpost shims?

We sell a lot of USE ones, purpose made, not just some metal crammed in there. They work well. Grease is your friend, BTW.

[steampunk]

as with Cinci Jim above my HSG-IT came with a 27.2 shim but was made for 30.9. the slot in the shim looked like a good wide open invitation for water and crud to get down in the seat tube so i just got a Thomson in 30.9.

if you can find the correct seatpost that would be the proper solution, but yes they will work.

[merlincustom1]

I'm told shims work fine. 4mm may be an aesthetic concern. Beats the expense of buying a new post and selling the old one here or on eBay, although there are a lot of 31.6 posts out there at varying prices. Is your cousin a purist or does he just want something that works, looks fine, and is easy? There's no wrong answer.

[merlincustom1]

Sorry, I mean your bro-in-law.

[R2D2]

Cane Creek makes a selection nice selectionof shims. http://store.canecreek.com/products/productdetail/Post+Shim+Converter/part_number=.ST2%2A/1739.0.1.1.31216.2352.0.0.0?pp=8&

[Fixed]

i used to use a beer can ..now i ride one
cheers imho

[jmeloy]

There's aPeg in my future and if I remember right it will need a 29.4 post. Are the USE shims the right way to go from the comments above? Thx!

[Fixed]

There's aPeg in my future and if I remember right it will need a 29.4 post. Are the USE shims the right way to go from the comments above? Thx!
lucky cat imho enjoy

[salem]

The one functional issue I could see with a shim: I've seen some manufacturers running very short seat tubes for a given effective top tube, and then a large diameter post to cut down on flex with the long extension.

This is usually more an issue on some mountain bikes. Personally, I once had an 18" frame with a 26.8mm Thompson post supporting my 34" inseam; the amount of flex was surprising (at 145#, there isn't much I flex) and unnerving.