But I gotta say that these potential problems give me pause.
Of course, it's like anything else, you only hear about the issues, generally. I have not really looked into the Progressive system much, but did not realize they were gas charged. There is certainly nothing wrong with a gas charged cartridge...in fact, Traxxion makes a gas charged, but if I'm not mistaken, it's application is more for racing, not street. Probably because the gas remains relatively stable regardless of conditions. But, if they leak, you're screwed. The AK-20's depend on the right amount, and weight, of fork oil to make them function properly, so in that sense there is less to potentially fail. It's also interesting to know that the life expectancy is 40-50K, which is no big deal for 90% of HD riders 'cause they'll never put that many miles on the bike either from lack of use, or trading it for a new one.
When I was over there last Spring getting the AK's put on the SERGU, I was talking with Max and a couple of their techs that actually build the cartridges...they are servicing enough of them now to know if anything is wearing out at the 50K mark, due to the huge GW market they have captured...when they service the forks, they check the cartridges for any signs of wear or abnormalities in the components. Some Wing riders put a LOT of miles on their bikes. Basically, no wear of the cartridge assembly itself, just the usual seals and fork oil that's seen it's better days. There's something to be said for in-house QC on parts that are spit out from a machine you're standing next to.
I really do wonder, just for curiousity, who makes both the Progressive Monotubes and also the new HD cartridges...