Last year I installed a set of those red All ***** fork seals in my KLX when doing the Gold Valve deal, and they lasted about 3 rides. Shortly afterward I learned that these fork and seal head units didn't have a good track record. Well, the seal head made it almost a year. I just replaced the seal head with a KYB unit from Race Tech. Here's a pic of where the All ***** unit failed, just like Rick at Cogent Dynamics suspension told me it probably would. See that nice little tear on the inner seal? Nope...not because of a dinged shaft or burr. Rick said the design allowed that inner seal to fold or twist in a manner that could cause this.

MSR and I believe Moose have been marketing these fork and shock seals under their own label, and maybe some others. I'd be leary of any red seals out there until you can guarantee that this has been corrected.

I did something a little different on the shock service this go-around. I'm using air instead of nitrogen in the bladder. I have easy access to nitrogen through the shop I used to work at, but my experience with high end MTB shocks, and pages and pages of discussion on Thumpertalk have convinced me that air will work fine. We'll see how it goes. I think there's a good deal of misinformation and urban legend going around about this.

 

Haven't messed with the rear shock yet. But the fork seals I have replaced with Moose's red seals. So far after I have been bouncing it around on the trails, no leaks.

 

I was going to say there was a difference due to thermal effects, but some research put that to rest. Experiments noted in the one place I checked proved that most all gasses gain the same pressure per degree increase in temperature.

The only reasons I could see for doing nitrogen over garden variety atmospheric air (gotta make it sound scientific) would be related possibly to moisture in that gvaa versus the purer nitrogen, maybe contaminants too - put a filter on that compressor. Corrosive chemicals in that air could be a concern, but I just don't see it. And let us not forget flamability should your shock spontaneously explode or should your bike burn to the ground. Nitrogen isn't flammable or flame supporting (I don't think). I think more research to verify the temperature/pressure thing would make sense and also the moisture/contaminant thing too. Of course how many of us can work a shock to the point where it actually gets hot? Not I.

Otherwise, what the heck air makes sense.

 

One of the shops that I inquired about suspension work told me flat out. If you have those all ***** seals, we won't put them in for you. My experience with other all ***** products has not been positive, so I avoid their products.

Air is almost 80% nitrogen, and my suzuki manual says air is OK, so I don't see a problem.

My shocks always get hot enough after riding that you don't want to touch them.

 

Thanks for the heads up on the All ***** seals, I'm looking to having to do mine in the near future. The film trick is just not cutting it anymore.

Do we got a good "how to" thread with pics on doing the seals and valves.

 

klx and zomby, this has been an interesting leaning process for me...long term and short term. For many years of servicing and modding high end MTB shocks, air has been the most standard gas for both the air spring in air shocks and the air in the piggyback shocks with an adjustable IFP...internal floating piston. One might contend that MTB shocks don't operate in as hostile an environment as dirt motor shocks do. That might have been more true at the dawn of MTB suspension bikes, but with the kind of riding done now and bikes with up to 10" of travel, they are way more alike in design and abuse than different. Two of my 4 MTB's have 6.5" of travel with both coil and air shocks with high and low compression and high and low rebound controls...not to mention floating piston piggybacks. Heck, most dirt motors still only have a rubber bladder in the piggyback.

On the issue of corrosion when using air, at the bicycle shop I work part time at, we've opened up air shocks that are 10 or more years old with no signs of corrosion on the aluminum and other metal parts. On my high end piggyback shocks that are several years old, I've been into them a couple of times for service, and there is no rust, corrosion, or other problem on any of the parts...none. You know...I'm thinking this might have been more of issue when shock bodies and some parts were steel, but most or all automotive, motorcycle, and MTB shocks in the performance end of the spectrum are aluminum or some other alloy. In our KLX shock and most others, the gases are contained inside a rubber bladder with an aluminum cap. The air or nitrogen never touches the shock body or other components. Anyway, this corrosion issue seems way overstated in this application.

On the heat expansion properties between nitrogen and air, many trustworthy charts were displayed on T-Talk that showed little real world difference.

On sourcing clean, high pressure air, anyone who's owned a decent mountainbike in the last few years knows what a high pressure shock pump is. These amazing little hand pumps will go to 300 psi with ease, they're relatively inexpensive, and they're very reliable. They're made by Fox, Rock Shox, and other companies. They also have valves that are no-loss, so you get the reading on the built-in guage, and that's what's in the shock or fork after you unscrew the valve. A nice thing about using air and a shock pump, is that you can constantly monitor and maintain the proper pressure in the shock.

Well, this is probably more than most wanted to know about shock service or nitrogen/air issues, but I'll get a first hand look at how it responds. I'm glad I've run this setup for a year with nitrogen, as I'll get to really feel any noticeable differences. The shock feels great right now.

 

Yep, more than I wanted to know... my brain hurts!

 

Yeah Mark, but it's not that hard to get your brain to hurt, is it?...LOL!

One other thing about nitrogen vs. air that I forget to mention is the potential safety issue in having that bladder filled with breathable air. If I do a water crossing that turns out a little too deep and get pinned by my bike underwater, I can poke that shock schrader sparingly and stay oxygenated until help arrives.

 

Are you sure you aren't McGyver in disguise?

I do like the thought process. Of course if you used helium you could float to the surface faster... and talk funny too!

Ouch... there it goes again!