Blue Roads

I've been searching for a 30mm seatpost clamp, with parallel clamping surfaces, and preferably no threads (pic below). If it has threads, that's probably okay as I can drill them out. I can't find one anywhere! I've spent time online and asked three LBS -- none found.

I'll be using it with a Pitlock locking seatpost clamp skewer. Pitlock sells such a seatclamp, but not in 30mm.

If somebody can point me to one, I'd sure appreciate it. Thanks.

arborohs

https://store.nexternal.com/shared/St...t=products.asp

arborohs

anyhow it's a GT clamp for cheap

Blue Roads

That GT might just work if I drill out the threads. Thanks!

Blue Roads

I bought the 30mm GT seatpost clamp, but the new design does not have parallel clamping surfaces -- in fact, not even close.

I also bought the Surly Constrictor seatpost clamp. It looked like it might work, but it also doesn't have enough parallel clamping surface to properly work.

If somebody can point me to 30mm seatpost clamp with parallel (outer) clamping surfaces, I'd sure appreciate it. Thanks.

DannoXYZ 

Why and what are you needing the parallel outer surfaces for?

operator

Pitlock.

pacificaslim

Maybe it'd be easier to get a larger one and shim? Or smaller and enlarge it?

Blue Roads

Great suggestion, thanks.

I asked my LBS about it today. I've got the 28.6mm and 31.8mm clamps that Pitlock makes, but the LBS said they are unaware of a shim that goes from 31.8mm to 30mm. Last week, a different LBS tried to spread the 28.6mm and ease it onto the seatpost tube, but it wouldn't fit.

I believe 30mm is an uncommon clamp size for aluminum or carbon frame bikes, but a common size for a steel frame bike. This is for a steel frame.

My search continues.

Edited to add: I want to add that I have front and rear Pitlock wheel skewers and the Pitlock headset lock, and all work very well. Also, the service from www.urbanbiketech.com is excellent.

operator

Steel frames don't generally take collars anyways. It's usually campy style integrated. You only really see 30mm on cheap new steel bikes for example that Jamis makes. You might want to ask yourself if your LBS is competent even for suggesting spreading a 28.6 collar to 30.0. That's idiotic to the extreme.

Blue Roads

It's for a Surly frame, all of which are steel. And all Surly frames, except for one, take a 30mm collar.

It was an LBS I don't often visit. The 28.6mm, of course, looks like a close fit to a 30mm. As I was talking with the guy, he grabbed a spreading tool and casually tried to see if it would fit. He knew it wasn't going to, but we were both curious. Afterward, he measured the tube with calipers and confirmed it indeed requires a 30mm.

HillRider

If you want to make a 31.8 mm collar fit you will need 0.035" (0.9 mm) shim stock. You can probably get this at an auto or industrial supply store.

I agree that trying to make the 28.6 mm collar fit was doomed to fail, particularly since you have to keep the clamp "ears" parallel.