seals dont fail because of pressure, they fail because of dirt or ice or nicks in fork legs
AirPro
- Thread starter Yamaha356
- Start date
seals dont fail because of pressure, they fail because of dirt or ice or nicks in fork legs
fork seals
how much pressure do you think is on your fork seals when you land after a triple jump.......20 psi ? maybe 300 psi.? If you study how an oil seal is made, the more pressure on the back side of the seal the better they seal.
If your forks aren't leaking oil now, they won't leak air when you add 20 psi.
In the early 70's there was a rush to throw away your springs and run only air and oil in your forks. AT the time we had Husky 250 and 360 gp bikes. We took the springs out of the stock forks, added more oil and just installed schrader valves and ran air on top of the oil in the forks.
Never had a fork seal leak. Never went faster either, so the next generation of Husky's we were back to running springs and just a few pounds of air on rougher tracks.
how much pressure do you think is on your fork seals when you land after a triple jump.......20 psi ? maybe 300 psi.? If you study how an oil seal is made, the more pressure on the back side of the seal the better they seal.
If your forks aren't leaking oil now, they won't leak air when you add 20 psi.
In the early 70's there was a rush to throw away your springs and run only air and oil in your forks. AT the time we had Husky 250 and 360 gp bikes. We took the springs out of the stock forks, added more oil and just installed schrader valves and ran air on top of the oil in the forks.
Never had a fork seal leak. Never went faster either, so the next generation of Husky's we were back to running springs and just a few pounds of air on rougher tracks.
I have not noticed any air leakage so far, my concern with that will be on the really cold days, but I will keep updates posted
More pressure on the back side of the seals might make them seal better, but it doesn't make them any stronger, and it might even make them more susceptible to damage from dirt/ice. Obviously, if you hook up a compressor and start pumping air in to your forks, at some point the seals are going to fail. How do you determine, for a given set of forks, at what pressure that is likely to happen? 60psi? 300psi? I haven't been able to find that number anywhere, but before I start pumping air into the forks I would like to know it. If you put 20psi into your forks and then compress them half way you have cut your volume in half and your pressure would now be 40psi. Go to 3/4 compression and you double again to 80psi. What if the seals are only good to 70psi? Maybe they're good to 300psi, I don't know. Don't get me wrong, I like the idea of the Airpro. It looks like a great way to be able to adjust on the fly, esp. for people that want to convert back in the summer. I just want to be as sure as I can of my equipment before I head out to the backcountry in the middle of winter.
H
hiltz
Member
With every aftermarket mod you do, there is a form of risk. A fork seal to me seems pretty minor compared to messing with an engine mod. I would imagine the boys at Airpro have tested and tested their product over and over. So far they seem like some wicked fellas and the customer service has been nothing short of amazing. So far my seals haven't popped out and killed anyone, I'll be out this weekend again and I have no doubts it'll hold it's own. I understand everyone wants something thats guaranteed, but remember your taking a machine built for dirt, throwing a large track on it and jumping off cliffs at freezing temperatures...
Wont hold air
I have the Airpro installed on my CRF450X and so far i can't seem to get them to hold air. Granted its been below freezing every time i try. Anyone else having this problem?
I have the Airpro installed on my CRF450X and so far i can't seem to get them to hold air. Granted its been below freezing every time i try. Anyone else having this problem?
8 rides in results
I have a few rides in with the air pro now. have found on the WR I like to run about 18-20 psi for trail/ tree riding, and I bump them up to about 25-30psi for jumping. The WR also has softer factory suspension than moto bikes. Have lost air pressure twice now but I think my hose routing is a little too tight. I carry my shock pump and psi gauge with for adjustments on the mountian and can 100% feel a difference with having air and not. Bottoming out is not a fun feeling, and I wonder if I maybe lose a little air everytime it takes a big hit. Pros-- adjusting stiffness throughout the day
Cons-- possible air leakage
I have a few rides in with the air pro now. have found on the WR I like to run about 18-20 psi for trail/ tree riding, and I bump them up to about 25-30psi for jumping. The WR also has softer factory suspension than moto bikes. Have lost air pressure twice now but I think my hose routing is a little too tight. I carry my shock pump and psi gauge with for adjustments on the mountian and can 100% feel a difference with having air and not. Bottoming out is not a fun feeling, and I wonder if I maybe lose a little air everytime it takes a big hit. Pros-- adjusting stiffness throughout the day
Cons-- possible air leakage
Make sure your airlines are pushed in all the way and seated.
air pressure
I have been riding my 13 ktm 500 xcw with air in the forks, about 12 lbs and I really have forgotten about the whole isssue, so that adjustment for me is pretty close. I have stiffer fork springs so if the air failed, no big deal, my front end is far from stock mush, just better now with some air. When I over pumped my pressure to the 25psi range, bike didn;t want to rail a fast berms on a road very well, felt like i wanted to stand up and beat on me a little. I like mine with that little bit of settled in ride sag and springy over the chop...........more oil will be the next experiment.
I have been riding my 13 ktm 500 xcw with air in the forks, about 12 lbs and I really have forgotten about the whole isssue, so that adjustment for me is pretty close. I have stiffer fork springs so if the air failed, no big deal, my front end is far from stock mush, just better now with some air. When I over pumped my pressure to the 25psi range, bike didn;t want to rail a fast berms on a road very well, felt like i wanted to stand up and beat on me a little. I like mine with that little bit of settled in ride sag and springy over the chop...........more oil will be the next experiment.
Its always the simple things that get ya! went out with some soapy water. The shader valve was a little loose. Holding 20 psi now. Im gonna try and get it dialed tomorrow!!!
How are these holding up in the extreme cold ? -20cel , how are they not going to fail like all the new AER 48's are ?
Ill let you know. I see 0 degrees F all the time and am sure in january ill see -20.
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UPsnowbiker
Well-known member
I just ordered a set. Hopefully worth it.
Running 20 psi in my forks on ktm 450 with yet 129 kit. It seems to be just right for my riding. Deep powder yesterday and no diving. I used most of the stroke a couple of times but no bottoming. Not quite right on the Fox Evols on the skid yet but close. Bottomed ever so slightly a couple of times. It is a work in progress. I love the ride that the bike/kit give. Much easier and more comfortable on whooped out trails than my Axys was. Carving steep side hills is stupid easy. I was crossing a big side hill above my friends on sleds while my left hand was in my lap. I was somewhat skeptical about the bike but I took the plunge and I am glad that I did. The only thing that I don't like is trying to get back on the bike in deep snow. It is tall and my hips are compromised. I found that stomping in a pad under my footing works pretty well in most cases. I kind of stuck it twice yesterday and it was a simple and easy effort to get it out. I am not near as tired after a full day on it as I was on the Axys.
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UPsnowbiker
Well-known member
Well I don't have any performance reviews yet but I can vouch for the customer service.
I was doing the very easy install and I wrenched too hard(can't say it's never happened before) and broke a piece. Definitely my fault. I emailed Charlie in the morning and he immediately threw 2 replacement parts in the mail no questions asked and no charge.
Performance review to follow shortly.
I was doing the very easy install and I wrenched too hard(can't say it's never happened before) and broke a piece. Definitely my fault. I emailed Charlie in the morning and he immediately threw 2 replacement parts in the mail no questions asked and no charge.
Performance review to follow shortly.
Spent about 3 hours on mine and I was looking for things to bottom out on and my forks remained stiff, I also rode in tempts around 0 F and it held air. I tree ride and will occasionally look for a pillow to pop off of to give you an idea of how I ride.
The customer service is second to none. I had problems installing on my 2007 KTM 300 XC-W because the air screws are apparently counter sunk deeper than the newer forks. I called and they immediately sent out updated fork nipples and rubber washers to shim the o-rings down free of charge.
