[300hp]

so,
now that I'm building a new frame and on a strict use parts I already have budget, I've been tinking with ways to un-suck the dhx air for my APP nickel.

From the same year, the DHX coil compression side is [piston] .700x.010, .700x.010, .700x.006, .600x.0045, .500x.0045, .400x.010 [bolt]

the DHX AIR from the same year runs [piston] .700x.010, .700x.010, .600x.004, .600x.004, spacer [bolt]

There are two more shims in the dhx coil, for a stack with noticeably more compression in comparison.

Is the light valving of the air an attempt to overcome the stiction of an air shock, or best match the ramp up of an air shock, or is this only on the DHX series, and from say, a ccdb air to ccdb coil, or vector air to vector coil, the shims and dampening range remain the same?

I'm thinking about setting the dhx air stack up to mirror the dhx coil. Thoughts on that? It makes sense to me as a reasonable increase across the range to keep the shock from wallowing with the VPP rate.

H/

 

[Jm_]

I thought the light valving was an attempt to wow customers on the showroom floor and make it seem as if it was super-plush AND lightweight (which it was in that setting). On the trail it was easily overwhelmed because air-springs don't rise up very much in the mid-stroke, it's only at the end-stroke, and that's precisely where the lack of damping would affect it terribly. Unless the bike was designed very specifically with the rate for the DHX air, it's going to be like that most of the time, and if it was then it would probably be more limiting because you couldn't get anything else to work on it well. The damping is most definitely different with the DHX air and I rode it on many bikes and never found one I thought was "well suited" with it. Changing the damping would probably be fun to do, even if you lost some initial "plush" it'd be a better tradeoff to pick up some mid-stroke support. I thought the DHX coil was a little less "plush" than the air version in some situations, it was just so much more consistent or varied terrain, which is what made it far better.

 

[Udi]

If I remember right (correct me if I'm wrong, it's been a while), the DHX air piston is different to the DHX coil one. Unless the piston's porting is identical along with the oil velocity through it, there's no reason to assume that the same shim configuration will give the same damping curve.

That said, I do think the valving on the air is on the soft side, when I opened one of mine up a few years ago the shims were noticeably deformed with bending marks on them. I don't think it'd hurt to beef up the stack, try it and see how it goes. Worst case you'll have to open it up again and take a few out.

 

[300hp]

Udi and JM,

Thanks for making valid points I had not considered. I don't know why I assumed the pistons would be the same between the shocks. Teh DHX AIR piston has noticeably more porting on it, so I assume higher flow. Since the change from the dhx air stack to the dhx coil stack isn't that much, I'm going to try and set the air stack up like the coil stack and try it from there.

Ok, the above aside, if you guys had to replace the shock on an APP bike (nickel, with a 2.25 stroke shock for 145mm travel) what would *you* think is the best match to the leverage curve, and put on your personal bike, and why?

Thanks guys,
H.

 

[Udi]

Ok, the above aside, if you guys had to replace the shock on an APP bike (nickel, with a 2.25 stroke shock for 145mm travel) what would *you* think is the best match to the leverage curve, and put on your personal bike, and why?

The Nickel's leverage curve could be considered linear, it is technically digressive-to-progressive like a lot of shorter travel VPP bikes (which is less than ideal, especially with an air shock) but thankfully to a much lesser extent - it just floats between 2.4:1 and 2.6:1 for most of the travel before dropping near 2.3 at the end.

If it were my bike, I'd consider a coil shock in this scenario, as the slight end stroke leverage ramp will help with bottoming, and fairly flat / slightly digressive start will be helped by a shock that isn't difficult to get moving at the beginning of stroke.

That's purely from a performance (not weight) standpoint however, and if I had to run an air shock I'd look for something that moved a little more easily at the start - options other than Fox perhaps. But I'm sure you can make whatever you have work relatively well. I'd run minimum boost pressure in the DHX-Air and a fully open bottom out adjuster to start off with. Less spring pressure and a slightly firmer compression stack will probably help too.

 

[300hp]

Hey, Udi,

Thanks for kicking ass and taking the time to give good advice.

viva la ridemonkey, MOAR SHIMZ, and interested what others in the know have to say.

H.