A discussion about shocks

[mrblaine]

its amazing the control you have over your ride.

Wouldn't it be easier to just swap in a cushy ride bump eating spring?

 

[kmas0n]

Wouldn't it be easier to just swap in a cushy ride bump eating spring?

Already did: that Jeep is on Rock jock coils. So smooth

 

[jjvw]

I added a slightly thicker rebound shim and then added what I'm calling a bleed shim.

For me, a bleed shim is simply another 0.008 shim under the main compression stack... this allows oil to pass through at low velocity with very little resistance. As soon as the velocity increases the oil must displace the shim stack like normal. Small bumps are completely gone. But as soon as you hit larger bumps the shock firms up normally.

...

Is this the same as a flutter?

 

[kmas0n]

Is this the same as a flutter?

Sorta,
A flutter is a small diameter shim in between the two largest diameter shims. Oil is forced to deflect the largest shim to get through the piston. That shim must deflect the next, which must deflect the next and so on. A flutter is effectively a space between the first two shims so the first shim can deflect some, before encountering the second. Eventually, the oil will deflect the first shim enough to contact the second, and valving gets firmer. This creates a small but very soft point in the valving when the shock reacts to a small low speed bumps.

A bleed shim is a small diameter shim between the piston and main shim stack. This allows some oil to freely pass through the piston without deflecting and shims. This creates a small but very very soft point in the valving. When shaft speed increases, oil will deflect the main shim stack too as the bleed shim is overwhelmed. The interesting thing about a bleed shim is it bleeds both ways. Compression and rebound. This is why I increases the rebound when I added the bleed.

Hope that makes since

I have both a bleed and flutter on my shocks and the are very soft, but firm up enough at high speed that I have jumped my TJ without a hard bottom out. My Jeep probably rides softer and has more body roll than most would care for, but that's what's fun about it. It's the way I like it.

 

[Brianj5600]

How should I be setting fluid level in my shocks?

One video I watched set the floating piston at a certain depth and basically topped off the body, but was a much shorter shock. I know I have lost fluid when changing shims but have no clue how much I've lost.

 

[kmas0n]

How should I be setting fluid level in my shocks?

One video I watched set the floating piston at a certain depth and basically topped off the body, but was a much shorter shock. I know I have lost fluid when changing shims but have no clue how much I've lost.

That's how I do it too. Set IFP, and fill up. Try not to trap any air. Will make a little mess when you put the piston in.

If the IFP is in the reservoir, put some oil in the main body, pull the IFP to suck oil into the reservoir. Get all the bubbles out, then set IFP depth.

 

[Brianj5600]

Any idea of the piston depth with a Fox 2.0 race series 12" travel and 11" cans?

 

[kmas0n]

8" down.

 

[Fughuert]

I watched this video and they didn’t mess with the ifp for just a revalve I assumed it’d be the same for a 2.0 smoothie. Am I wrong to try and follow this?

https://www.facebook.com/AccuTuneOffRoad/videos/how-to-revalve-a-fox-20-coilover/1865985607018546/
I also referred to this pdf https://cdn2.race-dezert.com/forum/data/attachment-files/2007/12/220474.Shock_revalve_pdf.pdf

About ready to start messing with this just need some spare time and the IFP comment has me doubting myself just checking.

 

[kmas0n]

The IFP is not a big deal. If you don't move it once pressure is released, it should stay put. You can double check but pulling the cap off the reservoir and measuring depth

 

[pcoplin]

You can bury the IFP all the way, then when you top off the fluid in the body, and push the seal head in to bleed, it'll push the IFP back just enough not to hit. That's how all the Fox shocks are coming from the factory now, even though the older documentation shows an 8in resi depth.


kmas, you can enlarge the bleed holes, or add more, to get the same effect as your bleed shim. The slow speed wallowiness you are feeling is due to the bleed side on the rebound being affected, you could also focus on messing with just the comp flutter if this still persists, since a flutter is a one-way bleed. Or up the rebound stack and all will be good? I haven't messed too much with a bleed shim. For leaf spring trucks that don't need rebound I do extra piston bleed, but for coiled rigs I always do the comp flutter, as I don't want to affect rebound.

Nice work learning yourself, and thanks for sharing. It took us a couple years of playing around and I'm probably still highly mediocre compared to the guys that do it for a living.

 

[kmas0n]

You can bury the IFP all the way, then when you top off the fluid in the body, and push the seal head in to bleed, it'll push the IFP back just enough not to hit. That's how all the Fox shocks are coming from the factory now, even though the older documentation shows an 8in resi depth.


kmas, you can enlarge the bleed holes, or add more, to get the same effect as your bleed shim. The slow speed wallowiness you are feeling is due to the bleed side on the rebound being affected, you could also focus on messing with just the comp flutter if this still persists, since a flutter is a one-way bleed. Or up the rebound stack and all will be good? I haven't messed too much with a bleed shim. For leaf spring trucks that don't need rebound I do extra piston bleed, but for coiled rigs I always do the comp flutter, as I don't want to affect rebound.

Nice work learning yourself, and thanks for sharing. It took us a couple years of playing around and I'm probably still highly mediocre compared to the guys that do it for a living.

Thanks, I'm learning as I go... unfortunately, there is no school for this, no courses, no textbooks I can find. Its just hands on trial and error. The pro's don't usually share their knowledge. So I spend a lot of time on the go fast forums chasing bread crumbs. I'm very happy with what I've got, but I know there is room for improvement.

 

[mrblaine]

The pro's don't usually share their knowledge.

Yes and no. There are a range of issues there. First is very few tunes are carbon copies of each other. Lots of folks just want the pro to give them a shim stack and have it work. A pro knows that would be unlikely and their name gets associated with a sub par tune because the owner bitches about the tune he got without divulging the circumstances. That isn't good for anyone.

Some pros have a few little tricks they've learned over the years purchased with a lot of sweat equity and trial and error, hard to give that away just for the sake of being a "nice guy".

99.9% of all tunes are a starting point for more trial and error after testing. The pro just gets there a bit easier with fewer tries generally.

No pro can give you a tune that will work first time without a lot of luck being involved. So the only thing they can really share is what changes to make to what effect. After that, it is more trial and error to see if that works for what you like.

I have a few pros I pay for the tune. I don't regret a single dime of the 1000's of dollars I've thrown at them over the years.

 

[kmas0n]

Yes and no. There are a range of issues there. First is very few tunes are carbon copies of each other. Lots of folks just want the pro to give them a shim stack and have it work. A pro knows that would be unlikely and their name gets associated with a sub par tune because the owner bitches about the tune he got without divulging the circumstances. That isn't good for anyone.

Some pros have a few little tricks they've learned over the years purchased with a lot of sweat equity and trial and error, hard to give that away just for the sake of being a "nice guy".

99.9% of all tunes are a starting point for more trial and error after testing. The pro just gets there a bit easier with fewer tries generally.

No pro can give you a tune that will work first time without a lot of luck being involved. So the only thing they can really share is what changes to make to what effect. After that, it is more trial and error to see if that works for what you like.

I have a few pros I pay for the tune. I don't regret a single dime of the 1000's of dollars I've thrown at them over the years.

I had the shocks on my JL dialed in pretty nice. When I added a winch, it fucked up everything. So I have to adjust the mid and high speed shims.
There is no one size tune fits all

 

[mrblaine]

I had the shocks on my JL dialed in pretty nice. When I added a winch, it fucked up everything. So I have to adjust the mid and high speed shims.
There is no one size tune fits all

Welcome to my personal hell dealing with folks and ride heights/shock tune. Bring it to me how you are going to drive it 98% of the time.

Well, I'm going to run a hardtop and no gear in the back 1/2 the time and then load it down for the trails the rest of the time.

Sorry, I won't touch it.

Why not?

Because I am not going to set you up with something that either sucks half the time or try to make it all work and have it suck all the time just not as much as it would half the time.

Make it work for both.

Nope, that isn't me. Bring it to me for its 98% use configuration or find someone else to deal with your shit.

Literally it shows up completely empty, nothing in the back, soft top on and then they want to know why it rides a bit harsh.

Because I know what you are going to do and that's load it down with all kinds of shit to hit the trail and if I set it up for how you brought it, all it is going to do is make you call me wanting to know why it bottoms out all the time.

Can you just stack some weight in the back close to what I carry and do it that way?

Sure, exactly what do you carry?

Just some stuff like everyone carries.

Can I just shoot myself now and get it over with?

 

[kmas0n]

Welcome to my personal hell dealing with folks and ride heights/shock tune. Bring it to me how you are going to drive it 98% of the time.

Well, I'm going to run a hardtop and no gear in the back 1/2 the time and then load it down for the trails the rest of the time.

Sorry, I won't touch it.

Why not?

Because I am not going to set you up with something that either sucks half the time or try to make it all work and have it suck all the time just not as much as it would half the time.

Make it work for both.

Nope, that isn't me. Bring it to me for its 98% use configuration or find someone else to deal with your shit.

Literally it shows up completely empty, nothing in the back, soft top on and then they want to know why it rides a bit harsh.

Because I know what you are going to do and that's load it down with all kinds of shit to hit the trail and if I set it up for how you brought it, all it is going to do is make you call me wanting to know why it bottoms out all the time.

Can you just stack some weight in the back close to what I carry and do it that way?

Sure, exactly what do you carry?

Just some stuff like everyone carries.

Can I just shoot myself now and get it over with?

But I want it all. Give it to me, I want it, its mine.

How much can DSC adjusters compensate for? Seasonal hardtop? extra passenger? 1000# of gear?

 

[mrblaine]

But I want it all. Give it to me, I want it, its mine.

How much can DSC adjusters compensate for? Seasonal hardtop? extra passenger? 1000# of gear?

The DSC can handle that, the ride height change can't.

 

[Fughuert]

Re-valved the rears tonight...The process is a very easy straightforward thing to do, anyone interested in trying this should not be dissuaded. The process took about an hour including taking off the wheels.

I measured what I had, a flutter'd 65 comp and a straight 30 rebound....too hard on compression on any event, and bridge expansion and speed bump type hits the whole chassis would lift. Not a good ride I'm not sure why a 30 rebound was used seems excessively light.

I copied kmas0n's compression stack and used a straight 70 rebound stack. Better on small stuff like gravel and washboard. Sliding around on gravel roads was controlled, still can identify as a miata on twisty backroads, actually feels a little better in that regard.

But still feels harsh through potholes and sharp dropoffs(like a curb). I can feel it be light initially but very quickly ramps up to a wall of stiff. Doing a little ledge climb it bucks coming over the top, more rebound needed if the 'bleed shim' is kept I think.

Not bad at all body roll wise even with an antirock it feels unchanged from before.

I have the LSC adjusters which I learned, months after purchasing, are not conducive to a good ride. Seen a few other forum discussions of people saying removing the lsc drastically improved ride without valving changes. Next I will try to put basic end caps on and maybe try a normal flutter but lighter and see how I like that. Then maybe copy it over to the front and see how that affects the rear.

 

[kmas0n]

Re-valved the rears tonight...The process is a very easy straightforward thing to do, anyone interested in trying this should not be dissuaded. The process took about an hour including taking off the wheels.

I measured what I had, a flutter'd 65 comp and a straight 30 rebound....too hard on compression on any event, and bridge expansion and speed bump type hits the whole chassis would lift. Not a good ride I'm not sure why a 30 rebound was used seems excessively light.

I copied kmas0n's compression stack and used a straight 70 rebound stack. Better on small stuff like gravel and washboard. Sliding around on gravel roads was controlled, still can identify as a miata on twisty backroads, actually feels a little better in that regard.

But still feels harsh through potholes and sharp dropoffs(like a curb). I can feel it be light initially but very quickly ramps up to a wall of stiff. Doing a little ledge climb it bucks coming over the top, more rebound needed if the 'bleed shim' is kept I think.

Not bad at all body roll wise even with an antirock it feels unchanged from before.

I have the LSC adjusters which I learned, months after purchasing, are not conducive to a good ride. Seen a few other forum discussions of people saying removing the lsc drastically improved ride without valving changes. Next I will try to put basic end caps on and maybe try a normal flutter but lighter and see how I like that. Then maybe copy it over to the front and see how that affects the rear.

Awesome!
I strongly encourage anyone who has invested the money into fox or King shocks invest the time to tune them to thier preferences. It's not a lot of work and very rewarding.

 

[Brianj5600]

Where are y'all buying shims. I think I'll buy #30, #50, and #70 for compression and #70 rebound stacks two of each. Is there a better way to get them?