Well, maybe more of a comparison. I have been using a Manitou 4-Way Air on one of my Bullits, and early this week I got a DHX Air to try on my other Bullit. Both shocks are 8.5 X 2.5 models. Both Bullits have 6" forks and weigh within a half pound of each other and have the same wheels and tires...pretty good for fair comparison.
Just like Renegade and Mk have commented recently, the DHX Air is a little tricky to set up. After some initial fiddling, I ended up with 175psi in the main chamber, 130 in the boost valve, the boost valve chamber half way in, and the Propedal 3 clicks off of full open. Some previous comments are really spot on about the DHX riding way into its travel without serious riding. In some moderately rough terrain, the travel indicator o-ring was pushed all the way down the shaft showing full compression, but I never felt a bottomout or harsh feedback. From watching and checking the shock stroke travel and o-ring position frequently, I would have perceived that the shock would be allowing the bike to wallow and be mushy and have noticeable bottomouts, but the bike didn't. The bike pedaled very efficiently, and it felt very balanced with excellent damping feedback. I was very pleased with how the bike rode, but was somewhat disturbed by the way the shock seemed to be performing mechanically. Frankly the whole deal was odd. I rode 15 miles during this period in an area that has some really rocky technical areas.
The Manitou 4-Way Air is a much easier shock to set up. It also has some way different setup parameters. BTW, I also have a 7.875 X 2.0 version on a Haro Extreme Werks that works flawlessly. My Bullit 4-Way has 110 psi in the main chamber, 105 in the SPV chamber, and the SPV chamber is fully open (backed out). You'll notice the dramatic difference in the main chamber pressure and the SPV fully open...very dissimilar. I know SPV and Propedal/Boost Valve technology are not identical. The 4-Way Air rides higher in its travel, doesn't blow through its travel (but gets all its travel), and is quite progressive for an air shock. The bike pedals very efficiently, a little more so than the DHX, but is still very plush. Frankly both the 4-Way Air and DHX Air ride a little plusher than either DHX 5.0 coil that I have, regardless of what spring or adjustments I fed into the coil models. This isn't saying the DHX coils were harsh or unsuitable, but most midstroke action and bottomout characteristics of the air shocks was a little better IMHO. I could see where really big hits from drops, g-outs, etc. might be handled a little better with a coil, but so far the 4-Way Air has been very capable.
Even though the monitoring of the DHX Air tends to indicate some weird characteristics, the performance was really quite good, and I feel some more fiddling may yield even better results...but that will have to wait. This morning when I took the bike out, the DHX almost immediately went into a "lock down" condition. My first thought was that I had a positive air chamber leak, but a check of the chamber verified that too much pressure had migrated to the negative chamber. No amound of depressuring and repressuring the shock would revive it (the Fox recommended method). After a call to Fox for any other ideas and the inevitable RA#, there was nothing else to do but send it back. My two DHX coils had to go back in their first month of use from the notorious "clunk", but they have been solid since then. Hey, stuff happens...especially to new stuff...so I'm not having an anxiety attack over it...LOL!
The Manitou 4-Way Air may be one of the best kept secrets in the high end air shock category. Both of mine have been used extensively and have performed excellently. It's a nicely progressive air shock that has some very good tuning capabilities. I also feel the SPV (Progressive/Curnutt) system is a little superior to the Propedal/Boost Valve technology for rear shock technology. It seems to produce a more controlled and predictable shock performance. I thought perhaps that my DHX was not functioning properly, but my experience (except the lock down) was almost identical to others who have posted here. I'm certainly not giving up on the DHX and will continue to thrash it when it returns.
Just like Renegade and Mk have commented recently, the DHX Air is a little tricky to set up. After some initial fiddling, I ended up with 175psi in the main chamber, 130 in the boost valve, the boost valve chamber half way in, and the Propedal 3 clicks off of full open. Some previous comments are really spot on about the DHX riding way into its travel without serious riding. In some moderately rough terrain, the travel indicator o-ring was pushed all the way down the shaft showing full compression, but I never felt a bottomout or harsh feedback. From watching and checking the shock stroke travel and o-ring position frequently, I would have perceived that the shock would be allowing the bike to wallow and be mushy and have noticeable bottomouts, but the bike didn't. The bike pedaled very efficiently, and it felt very balanced with excellent damping feedback. I was very pleased with how the bike rode, but was somewhat disturbed by the way the shock seemed to be performing mechanically. Frankly the whole deal was odd. I rode 15 miles during this period in an area that has some really rocky technical areas.
The Manitou 4-Way Air is a much easier shock to set up. It also has some way different setup parameters. BTW, I also have a 7.875 X 2.0 version on a Haro Extreme Werks that works flawlessly. My Bullit 4-Way has 110 psi in the main chamber, 105 in the SPV chamber, and the SPV chamber is fully open (backed out). You'll notice the dramatic difference in the main chamber pressure and the SPV fully open...very dissimilar. I know SPV and Propedal/Boost Valve technology are not identical. The 4-Way Air rides higher in its travel, doesn't blow through its travel (but gets all its travel), and is quite progressive for an air shock. The bike pedals very efficiently, a little more so than the DHX, but is still very plush. Frankly both the 4-Way Air and DHX Air ride a little plusher than either DHX 5.0 coil that I have, regardless of what spring or adjustments I fed into the coil models. This isn't saying the DHX coils were harsh or unsuitable, but most midstroke action and bottomout characteristics of the air shocks was a little better IMHO. I could see where really big hits from drops, g-outs, etc. might be handled a little better with a coil, but so far the 4-Way Air has been very capable.
Even though the monitoring of the DHX Air tends to indicate some weird characteristics, the performance was really quite good, and I feel some more fiddling may yield even better results...but that will have to wait. This morning when I took the bike out, the DHX almost immediately went into a "lock down" condition. My first thought was that I had a positive air chamber leak, but a check of the chamber verified that too much pressure had migrated to the negative chamber. No amound of depressuring and repressuring the shock would revive it (the Fox recommended method). After a call to Fox for any other ideas and the inevitable RA#, there was nothing else to do but send it back. My two DHX coils had to go back in their first month of use from the notorious "clunk", but they have been solid since then. Hey, stuff happens...especially to new stuff...so I'm not having an anxiety attack over it...LOL!
The Manitou 4-Way Air may be one of the best kept secrets in the high end air shock category. Both of mine have been used extensively and have performed excellently. It's a nicely progressive air shock that has some very good tuning capabilities. I also feel the SPV (Progressive/Curnutt) system is a little superior to the Propedal/Boost Valve technology for rear shock technology. It seems to produce a more controlled and predictable shock performance. I thought perhaps that my DHX was not functioning properly, but my experience (except the lock down) was almost identical to others who have posted here. I'm certainly not giving up on the DHX and will continue to thrash it when it returns.