Got a frame with a 30.9 ID seat tube, which is 33.1 external diameter.

A 34.9 clamp works on it, but isn’t ideal.

Other than Salsa – which appear to be like hen’s teeth in this size – what are the other options?

Given the option, I’d also rather buy British.

which bastard of a framebuilder went with 33.1?

EDIT: Bontrager do a 33.0mm non-qr and with a forged cable stop which you could file off for about £6.

which bastard of a framebuilder went with 33.1?

😆

That’d be me.

Wanted the mid-ground between 27.2 flex and 31.6 rigidity, after my old Brodie Holeshot (with a 31.6 post) used to feel like it was trying to get intimate on longer rides. Running a dropper was also a must.

I think the Ragley seat tubes were that at one point. I had shims made to fit them to normal clamps.
The Stif Morf would have the same problem but has a shim brazed to the top of the seat tube.

I think the Ragley seat tubes were that at one point. I had shims made to fit them to normal clamps.
The Stif Morf would have the same problem but has a shim brazed to the top of the seat tube.

Worth knowing – cheers Brant.

I think the Ragley seat tubes were that at one point. I had shims made to fit them to normal clamps.
The Stif Morf would have the same problem but has a shim brazed to the top of the seat tube.

http://www.chainreactioncycles.com/ragley-seat-clamp-shim/rp-prod80055

Perfect! 0.1mm bigger as tube is painted 🙂

My Pipedream Skookum requires a 33mm clamp. KCNC make one >>>

https://clee-cycles.co.uk/P913/product

Ti bolt too for extra points

That looks spot on. Cheers!

Edit: link to clamp posted while writing this. Fortunately the above can apply to both the clamp and the shim.

Braze-on binder bolt is the easiest option to get around the weird OD, no?…

Paul Component do a 33.1mm QR seat collar:

Quick Release Seat Post Collar

I’m still looking for a non-QR one that will clamp strong like the Thompson collars.