whats the difference between 'Air U-turn' and 'Dual Air'?

SMITHY D

Just a quick question - whats the difference between 'Air U-turn' and 'Dual Air'?Why is U-turn more expensive than just dual air - i guess you're getting something extra, but what?

Smithy :?

nicklouse

one allows you to change the travel of the fork one is just an air spring.. all the info is on Srams webby.

SMITHY D

So U-turn allows more adjustability (sat 85, 100, 115mm), whereas dual air will just be fixed on a certain amount of travel (100mm), however it will also be a lighter fork?is that correct?

Smithy

Stu 74

Yes U turn allows you to adjust the travel by twisting a knob on the crown of the fork. For example, U turn Pikes can be adjusted from 140mm down to 110 mm. Each complete revolution of the knob winds the forks down 5mm.

I'm guessing that forks without this feature will be lighter but, as Nicklouse has pointed out, you will have to check the manufacturer's website.

Stu

nicklouse

SMITHY D wrote:

So U-turn allows more adjustability (sat 85, 100, 115mm), whereas dual air will just be fixed on a certain amount of travel (100mm), however it will also be a lighter fork?is that correct?

Smithy

not quite, U-turn is set it to what you want in the range.

SMITHY D

Cheers guys!
That answers my question nicely!
One other thing...when setting the pos and neg pressures in the fork for your particular weight and ride, does it not matter what amount of travel the fork is set to at that time?
Do you really alter the amount of travel that much during a ride?

Smithy

nicklouse

if U turn set it fully open.

As it says in the manual.

stumpyjon

Do you really alter the amount of travel that much during a ride?

Depends on your ride style, where you're riding and the bike. I have Fox Talas forks on my Stumpjumper which give me 100mm, 120mm & 140mm of travel and I swap the travel all the time (it is a lot easier with the Fox forks as you only have to turn the dial an 1/8 of a turn to change travel by 20mm). I find the Stumpy needs it's nose down on steep climbs. My hardtail however which doesn't have adjustable forks seems perfectly happy climbing or descending at 100mm, there again I wouldn't personally ride the hardtail around a trail centre for example.

dave_hill

SMITHY D wrote:

Do you really alter the amount of travel that much during a ride?

Absolutely. If I have a prolonged climb or a long run on tarmac I'll wind my Pikes right down to 110mm.

If I have long descent to do, all the way out to 140mm. The rest of the time I run them mid-way at 125mm.

To be honest I can't see the point of having micrometer adjustment (as with U-turn) - I think that the Talas idea is far better. I never set my forks between 125 and 140mm so what's the point?

What no one has pointed out though is the function of the Dual Air system - it allows you to fine-tune the bump sensitivity of the forks by balancing two air springs. The positive spring effectively "props up" the fork, while by adding or decreasing air to the negative spring regulates how far into its stroke the fork sits at rest.

The routine for setting up a Dual Air fork is to set the sag with the positive chamber (the negative spring should be almost empty), then charge the negative spring to determine how much force is needed to activate the fork.

RS air-sprung forks have three platforms - Solo Air (positive spring only); Dual Air (positive and negative springs); and Air U-turn (positive and negative springs with travel adjust).

SMITHY D

Top answer Dave!!
Thanks for the problem solving mate!At the moment i'm riding a Scott Scale 30 and i want to upgrade the forks, but I was unsure whether to got for dual air or dual air plus U-turn. As its a XC bike, and thats pretty much what i tend to ride, i think i'll stick with the 100mm travel and go for dual air only. May be a set of 2009 Rebas?I'll keep the U-turn stuff to an AM machine.

Smithy

GT Destroyer

With my Air Pikes. I often find that I change the travel whilst on the bike, as quoted it is extremely handy for uphills etc....

I often find that I have to top-up the air in the -ve and +ve chambers. I have it set to the max (I think 170ps). So if you get air adjustable forks, you may find yourself having to "pump" them up now and again.

dave_hill

GT Destroyer wrote:

I often find that I have to top-up the air in the -ve and +ve chambers. I have it set to the max (I think 170ps). So if you get air adjustable forks, you may find yourself having to "pump" them up now and again.[/color]

In that case it might be worth getting them serviced - mine are exactly the opposite. I checked them for the first time in about 6 months last weekend and they were at more-or-less exactly the point where I'd set them.

Anonymous

i always found uturn to be a bit of a faff and once set at max travel, its where i leave it. my rebas go from 115 to 80mm and it a pointless adjustment for me, my old pikes were 140 to111 i think but again, i just left them alone.

as said before, the talas system seems much more usefull as there is a decent amount of travle adjust and it is much quicker than stopping to wind up or down on uturn.