On-one 456
is it a 30.0mm
anyone

Yes. Shame a lot of the useful info has disappeared off their new website.

29.8, not many makes do them, I got one by spank. Some makes of 30mm will work others won't even if they do its not ideal.

will Hope 30.0mm work?

Does on my Inbred which has the same seat-tube. And on my Pompino. I've used Surly and Brand-X clamps in 30.0mm too.

cool cheers lads!

woodman fits aswell, can buy them at je james pretty cheap

On ones own clamp is simple and works very well, make sure you get one with a brass shim rather than a cheap plastic one. The plastic ones compress and the clamp will slacken, mine did.