Can’t seem to find the answer to this anywhere. I’ve got a 2010 Reba Race which has been set to 120mm but it seems to be getting shorter originally the exposed stanchions measured around 130mm yielding 120mm but recently they have shortened to 110mm of exposed stanchion. Pulling up on the fork it extends but it doesn’t get to the full length that it once was and then it settles back at its reduced length.

The fork holds air perfectly and the negative chamber has less in than positive so that shouldn’t be pulling it down.

Anyone have any ideas or had a similar problem.

Only thing I can think is that the negative chamber does indeed have more pressure in it, your positive air chamber is losing pressure somehow (or the air is transferring between the two chambers somehow? Is that possible even?), and your gauge is giving you false readings. I just pump mine up until the feel ‘right’, sod what the gauge sez. They’re not very accurate anyway really, I find.

I bet the feel smoother though, eh? More in the negative air chamber makes them feel nicer at the expense of a bit of travel.

If the gauge was faulty then the error would be the same in both positive and negative chambers. Its not loosing air which is great.

I guess the problem really is the fact the front end of the bike sits lower than it should all the time and with the sag even lower.

try letting all the air out of the -ve chamber

then pumping the +ve to the correct pressure

then pumping the negative to your pressure of choice

that might sort it – if you keep tweaking the -ve and +ve without following the above process things can get out of whack

Likely cause is air going from the positive chamber to the negative which is pulling the forks down . Take them back , 2 year warranty on all things Sram .

Hi Orange Lad,

If its a 2010 fork its more than likely that they just need a service and renewal of the air seals rather than a warranty issue.
Dual Air seal kits are about £10 and fairly straight forward to fit for a competent home mechanic.
While you have them apart check the inside of the left stanchion for any small scratches that might allow air to pass over the seal.
Please feel free to contact us on 015397 32262 mon-fri for further help or parts.
Regards
Robin

You is getting fatter 😉

Have the same issue on a pair of 115mm 2007 Rebas.

I think it is worth setting it up as grevioustim said – I can never be arsed, but when I do take the time it seems to help.