[DanielM3]

I have been trying to tune my fork and am running into a situation that if I change the negative pressure then I will increase or decrese travel no matter the UTurn setting. If I let all negative pressure out then it will be full travel. Is this normal? I was just trying to increase the negative pressure a bit, but I want full travel.

Thanks

Daniel

 

[Hardtails Are Better]

In any dual air fork, if you put too much negative air in, you will loose travel. This is because the high pressure in the negative chamber will be enough to compress the positive chamber a bit, which lowers the fork.



If you have to remove ALL the negative air to get full travel, there is somthing wrong with your fork.

 

[The Great Stonk]

theirs no realistic reason to run more negative air then positive air anyways to be honest.

all it does is put extra pressure against the seals, and gives you less travel.

try a lower positive pressure with equal or less negative pressure if your looking for a more responsive ride.

 

[DanielM3]

thanks

hey guys thanks for the help. i was just reading the manual and going off of their suggestions for tuning. thanks for the input, I will back off the negative to get full travel

 

[CharacterZero]

I set them equal- fork shows 140.

 

[crisillo]

Yep.. equal pressures (or 10 psi less on the negative) works great on mine

 

[kcavtca]

Negative pressure can't be "higher" than positive at full travel

My neg is 5-10 psi less than pos psi. Just keep dropping the pressures, and keeping the stantions lubed and you'll figure it out. Give it a chance to break in the seals a bit too (10-20 hours).
The physics of the Pike air set-up with pos and neg chambers dictate that if the pos air is set up first, and then the neg is pumped up, if you surpass the pos pressure you just set, then the pos chamber will simply begin to compress. Basically, you can't put more pressure in the neg than the pos...they just equalize. This is why people are saying that 5-10 psi less in neg than pos gets plushness without travel loss.

BTW - The manual I had in for my '06 listed pressures way to high.

-kcav

 

[SingleTrackHound]

Some actually run more neg for a specific needs. For instance, you want to run Pike Dual Air 110-140mm on a 100mm suspension bike. But you don't want to upset the frame's intended geometry too much by installing a longer fork. So you crank down the u-turn to lowest travel at 110mm from your normally ran "balanced" pos and neg psi. Then you simply pump more neg psi until the travel decreses to 100mm. It is not recomended have a neg psi much greater than pos but lessening 10mm travel will not harm the fork.

As long as you undertsand your specific needs, you can tune the dual air fork to many applications.

 

[The Great Stonk]

Some actually run more neg for a specific needs. For instance, you want to run Pike Dual Air 110-140mm on a 100mm suspension bike. But you don't want to upset the frame's intended geometry too much by installing a longer fork. So you crank down the u-turn to lowest travel at 110mm from your normally ran "balanced" pos and neg psi. Then you simply pump more neg psi until the travel decreses to 100mm. It is not recomended have a neg psi much greater than pos but lessening 10mm travel will not harm the fork.

As long as you undertsand your specific needs, you can tune the dual air fork to many applications.

and by doing this you will barly get anything usful from the fork, since it will already be a long way into its travel, it will ramp up like hell and generally not perform...

over pumping the neg is no substitute for having the correct length fork.

from my experience nothing good (suspension wise) can come from over charging the neg chamber, once it goes above that of the positive, it doesnt get plusher, it doesnt get more active, it just sucks the fork down and takes away the available travel.

 

[SingleTrackHound]

and by doing this you will barly get anything usful from the fork, since it will already be a long way into its travel, it will ramp up like hell and generally not perform...

over pumping the neg is no substitute for having the correct length fork.

from my experience nothing good (suspension wise) can come from over charging the neg chamber, once it goes above that of the positive, it doesnt get plusher, it doesnt get more active, it just sucks the fork down and takes away the available travel.

You are correct.:thumbsup: It is not an ideal nor proper thing to do to replace the "true" 100mm fork. But it is an option that you do have if you happen to be in a pinch or want to simply experiment. Many of us like to tinker with our mt bike. One of my friend like to add 260lbs psi on his Specialized Enduro 5" bike's Fox rear shock. He only weighs 170lbs. He barey gets 10% sag and rarely use more than 70% of his stroke. He knows that it's not the proper thing to do. Trust me, I gave him all the reasons why he shouldn't . But does that because he likes it: less bob, never bottoms, and stiffness. Go figure.