[ChrisRobin]

Why would increasing LSR affect LSC?? Today I was tinkering with my Fox 38 and with my weight and Luftkappe piston in there, it put me at the top end of the recommended Fox air pressure. It also asks to max out the HSR and one click out on the LSR. But when I do that, the fork feels extremely stiff as if there's tons of stiction. As soon as I back off the LSR a few clicks, the fork then moves freely again. Why is that??

 

[johnbryanpeters]

Why would increasing LSR affect LSC?? Today I was tinkering with my Fox 38 and with my weight and Luftkappe piston in there, it put me at the top end of the recommended Fox air pressure. It also asks to max out the HSR and one click out on the LSR. But when I do that, the fork feels extremely stiff as if there's tons of stiction. As soon as I back off the LSR a few clicks, the fork then moves freely again. Why is that??

Termites.

 

[StiHacka]

But when I do that, the fork feels extremely stiff as if there's tons of stiction. As soon as I back off the LSR a few clicks, the fork then moves freely again. Why is that??

Extremely stiff when riding or when standing and just pushing the fork down? If the former, it packs up on consecutive hits? If latter, .

 

[ChrisRobin]

When just pushing down on the fork. It's almost like when fully closed or close to being closed, the LSR somehow restricts oil flow during fork compression. I'm not sure if that is possible or not.

I'm hoping to go for a ride tmo and see how it is on the trail. I'll test a couple things.

 

[Kanye West]

That's normal. The rebound needle is a two way needle valve. There are 4 ways for the fluid to pass from the compression chamber - compression needle valve, base valve (the VVC in your case), the midvalve shimstack, or the rebound needle valve. 2 needle valves (fixed), 2 blow off valves (variable).

Unfortunately for heavier riders or lighter riders, you really only get control over 50% of your flow area (approximately) for low speed control since the needle geometries are similar from comp to rebound. If you're heavier and stay maxed on the rebound needle setting, there's half your low speed flow area gone. If you're lighter and that rebound needle stays mostly open, there's only so firm your LSC can be since there's a big gaping hole at the other end of the chamber. You only end up closing off half of what you might ever want to.

Very high end kit suspension in the moto world has all these needle valves checked so there's no interplay. Just expensive and creates a different tuning baseline with less field data to draw from because it's not the original configuration.

 

[ChrisRobin]

Ok, thanks for the info. That's what I was sort of picturing but couldn't really put it into words.

In the Fox 38 manual, if you're about 240-250lbs, you need an air pressure of 123psi with HSR closed off and LSR one click out. As I've tested in the parking lot, you can't run the fork that way. Fox must have tested it and figured "ah whatever". An RC2 damper would be killer right now.

I'll email Vorsprung and let them know the fork damping adjustments becomes shitty at those pressures.

 

[Kanye West]

Close off the HSR and use the LSR as your adjuster. If you feel it sticking down and can't get it fast enough with the LSR, back off the HSR one click at a time.

The way the VVC thing works is to change the stack stiffness rather than the preload. It's equivalent to a "revalve". So exhaust your low speed options because shifting everything else around with the high speed. There are only 8 clicks so your spot is probably in one of those final 3 clicks.

I'm not that far off. I'm 175-180# and I run around 105-110psi (generally a firmer setup). The manual recommendations for the rebound were stupid unless I'm riding REALLY loose terrain or bike park jumps. The crossover was the first thing I noticed with the rebound, along with a pretty useless compression adjuster range.

 

[englertracing]

Very high end kit suspension in the moto world has all these needle valves checked so there's no interplay. Just expensive and creates a different tuning baseline with less field data to draw from because it's not the original configuration.

Fork rebound is never check valved
Shock rebound adjuster is sometimes partialy check valved... but not always...

 

[ChrisRobin]

Ok I'll try that tomorrow. Thanks.

 

[Kanye West]

Fork rebound is never check valved
Shock rebound adjuster is sometimes partialy check valved... but not always...

They sure are on factory stuff. All the compression bypass on the midvalve goes through the shimstack float, so the compression response remains agnostic of rebound clicker setting.

Couple companies make aftermarket separator valves for the fork midvalve shaft nut same as the rear shock shaft nut.

 

[ChrisRobin]

I tried 125psi today with HSR about 2 clicks out and LSR 5 clicks out. Felt pretty good...although it was a lot of climbing today and the descending was kinda flow-y. I'll have to test her out on a much harsher trail next time.

 

[englertracing]

They sure are on factory stuff. All the compression bypass on the midvalve goes through the shimstack float, so the compression response remains agnostic of rebound clicker setting.


Couple companies make aftermarket separator valves for the fork midvalve shaft nut same as the rear shock shaft nut.

Your first sentence is correct, and explains why a check nut would be useless on a mid valve.

Second yeah race tech and a some other companies make their own checked nut, which usually ends up with a bleed hole drilled in it aka partially checked... and I'm sure not all "high end" suspension use them. You can also find them on some stock sachs shocks.

 

[Kanye West]

Your first sentence is correct, and explains why a check nut would be useless on a mid valve.

Second yeah race tech and a some other companies make their own checked nut, which usually ends up with a bleed hole drilled in it aka partially checked... and I'm sure not all "high end" suspension use them. You can also find them on some stock sachs shocks.

Not useless. It achieves the desired effect, which is removing the interplay between the rebound bypass and the compression bypass. Nothing wrong with it as long as the rest of the system is tuned accordingly.

Baseline for the true A-kit stuff have the rebound bleeds checked front/rear. It can be replaced with a standard nut.