Hi, i recently got a new hardtail and it has a set of rock shox reba air u turns on it, i had a mess about with the u turn the other day and put some air in them etc and now they only extend to 105 mm not 120mm travel? Any ideas on how to fix this?

Nice one!

Sounds like you've put too much air in the negative air chamber (the one on the bottom of the leg, not the top).

-ve and +ve chambers should be roughly the same pressure wise, but set the +ve chamber first.

right!!!!! So should I let all the air out of both first? What does the -ve air chamber do by the way!!!!!

Let all the air out of the -ve chamber, set the pressure in the +ve chamber to your desired pressure, then pump the -ve chamber up to the same pressure once you've done that.

The -ve chamber is there to make the fork more supple in its initial travel. Running the -ve chamber empty, the fork will not react to small bumps very well at all. Running it too high and it will be very supple initially, but will eat into your available travel. The best bet is to match the pressures, therefore not eating into the travel but making it as supple as possible initially.

Cheers Maverick!

Sorry one more question do i need to anything with the u turn travel adjuster? Ie set it at max or low when I do this?

No worries

Good last question, to which I'm afraid I don't know the answer. I've only got normal non-U-Turn Reba's myself. I'd assume (but check first) that you'd probably open up the adjuster to max travel before doing so… Anybody with a Pike, Revelation or any other Air U-Turn rockshox fork should be able to help though, it's not Reba specific.

You should have your u-turn adjuster wound right out (full travel) before fiddling with air pressures.

Thanks troops!!! Typical bloke did i go on the webber and look up some instructions? Nah I dont need them!

Nice one !