I am looking at buying this Miyata airseat to put on a KH36 frame which requires a 27.2 seatpost.
Does a 27.2 seatpost exist that allows a miyata bolt pattern?
Just saw this.
It is a last resort, but I’d really rather avoid using the rail and rail adapter set up.
What size is the standart Miyata seatpost?
What about a shim?
Looks as if you can get both a 25.4 and 22.2 from the UK site. I guess a shim would work (says so in the description on UDC) but I have no experience with them.
I used in my Koxx Devil frame. I never had any problems, just tight well your seatclamp and it works perfect!
I used it once in my KH Frame too to test the QU-AX reinforced Seatpost and it works perfect.
I don’t know for long distance, but for street and trials it work well! And it’s cheap!
OK well that sounds like a decent plan. The uni will be used for mainly on-road riding, so I can’t see there being too much twisting on the seatpost.
Which shim did you use Pedro?
The Koxx Shim was 29.2 to fit the Pit Fighter (27.2), and in the KH Frame I used a 27.2 to fit the QU-AX seatpost (25.4 I think…).
I use the 27.2 to 25.4mm shim in my kh 07 frame. It’s perfect. Used to have a 29.2 to 27.2 in my koxx devil frame and that worked fine as well. Never had any problems until i tried to fit the 29.2mm shim in the kh frame which is 27.2 
I’d go for it, the only thing is that 22.2mm posts are quite weak, but the shim shouldnt be the problem. I put a bit of grease in mine so the post comes off nicely. Some grease on the outside and inside of the shim. Getting those shims out can be really hard work, pair of very grippy pliers shoudl do though.
OK, well if the 22.2 is too weak I could probaby find a 25.4 miyata seatpost.
Thanks for the info.
22.2 would be fine for a distance uni, its only really an issue for people riding street or going big in trials. Plenty of people use 22.2 in freestyle with no issues and all of Darren’s trials and muni frame take 22.2.
I’ve had troubles with 22.2mm on my freestyle uni. Then again, I do flat on it lol.
A shim would definitely work. It’s that simple.