Seat post shims

Took delivery of a bizango pro yesterday, takes a 31.6mm post, I’ve been struggling to to find a brand x 150mm post for it, had a few ordered cancelled due to stock errors. Last one delivered was sold as 31.6 but it’s actually 30.9. toying with the idea of sticking a shim in and be done with it. Are shims still a thing, any issues doing this or just wait till I can find one the right the size?

Shims are fine, I’ve been using them for 25 years without problems (in fact, Giant used to ship bikes with a 27.2 mm seatpost and shim to fit a 30.8 mm seattube.) Just make sure you get a good quality shim that is at least 100 mm long. The shim should extend down past the bottom of the top tube-seat tube junction.

Again, been using them for years, never had an issue. Also great for not getting posts seized in the frame!

Also great for not getting posts seized in the frame

Yes, this is an underappreciated benefit with dropper posts. Lube the inside of the seatpost and the shim won’t seize to it, but the seatpost won’t slip because you don’t need grease between the seatpost and shim. Even if the shim welds itself to the seatpost, you can just pry it off with a screwdriver.

Yeah, fine.  Just buy a decent anodised one like a USE or equivalent.  I’ve got a 30.9 AXS reverb shimmed to a 31.6 frame.  A mate had a cheap Chinesium shim that bonded itself to a post however as it wasn’t anodised.

the advantage of the shim approach is that its more likely your post is re-usable if you swap frames in future. The disadvantage is less room for bushings etc within the post, so if you’re a big lad you might find a bigger post is worth hunting.

merlin has the oneup in stock https://www.merlincycles.com/oneup-components-dropper-post-v2-263777.html?utm_source=PHG&source=PHG&utm_medium=Affiliates&utm_campaign=genieshopping

you can also run a longer one-up and limit the drop (creating a stronger solution)

Last time I needed to shim a 30.9 post into a 31.6mm seat tube I used a drinks can I found in the street. I think a Monster can was the best fit.