Shock Tuning

Higher spring rates can increase bouncy feeling. Do you have a heavy front bumper?

 

higher spring rates increase bounce, then you reduce the valving to get rid of the bounce.

thats the point of tuning

 

Wouldn't reduced valving have less effect over the piston? Allowing more free movement?

 

its not that simple. Depends on which shaft speed you are targeting. for bounces on the road, those are slow speed shaft movements and are controlled by the largest shims; the 1.8 and 1.6

For whoops, jumps, and G outs those are controlled by the high speed shims, The 1.425 and smaller shims

For road bounces after swapping springs, make the larger shims thinner. But you should have a flutter in there. So start with the face shim, then if need be adjust the 1.8 on the main stack

 

No, I don't have a heavy bumper, but I will at some point.

 

...

 

I think the issue in referencing the shims as high and low speed is that it implies one isn't affected by the other, or that low speed shims aren't engaged during high speed events, or high speed shims aren't engaged in low speed events.

it might be better to describe the largest shims as active on *every* shaft movement, and the high speed shims activated to their full motion in the highest speed shaft events.

I'll let others carry on the argument over which action in a truck qualifies for high or low speed shaft movement.

 

Here we go again.

 

This topic is great. Its just am not long travel and will never be most likely. Can help be directed towards us MT guys? I have Fox 2.5 dsc extended travel and it drove horrible when i went to mojave such a harsh ride even with stock ltx tires at 20 psi. I wont be speeding on trails. Just need it to handle much better then what it comes from fox factory. Need to make it back to NYC in one piece. And am not afraid to work on my own vehicles.

 

but, but, why?

thanks for this. i only played a little bit with my tubes over the summer. still need to put the new shim stacks (compression with flutter and rebound) in the coilovers.

 

Alex got a thorough ball washing today. This is why he still loves the forum. Lol.

 

For bounces on the road, those are slow speed shaft movements and are controlled by the largest shims; the 1.8 and 1.6

For small road and trail bounces make the larger shims thinner. Start with the face shim, then if need be adjust the 1.8 on the main stack

For whoops, jumps, and G outs those are controlled by the high speed shims, The 1.425 and smaller shims

If you want better bottom out control, increase the thickness of the smaller shims. The 1.425 is an "in-between" shim. Play with the number and thickness at your discretion. But I suggest sticking to the Fox recipe. So play with the numbers of large shims, making sure you dont have more 1.6 and 1.425 shims than 1.8. Dont mess with the numbers of 1.350 and smaller, adjust the thickness of them as a group. You basically have two choices for high speed, 1.350 and smaller make them all 0.015 shims or make them all 0.020 shims.

So to reiterate, the 1.350 and smaller is one group. two variables, 15s or 20.

The large shims 1.8, 1.6, 1.425 are a second group. Two variables, the thickness and the number. The larger the shim, the smaller the bumps it affects.

Dont forget about the flutter, its a very important factor.

Kevin, you should stop thinking of ways to argue with me about this and start thinking about what Im saying so you can understand the concept.

Yes, tuning a MT truck is exactly the same as tuning a LT truck. You just have to understand that your suspension travel is less. So the "whoops" you would tune for will be much smaller. and the "jumps" and "G-outs" are going to be smaller as well.

Most guys dont care to try to tune an MT truck, but I can help you. The first step is to open up your shocks and tell me what stacks you have in there and then together we can see if there is room for improvement

 

Good thing i saved the old shocks. Would the stacks have the specs stamped on it ? And would calling fox have the information?

 

no the best thing is buy a set of dial calipers and measure them yourself. There nothing like taking control of your own parts and knowing exactly what you have

 

Hey Alex, so I have the ADS triple bypass w/clickers in the rear and the knob adjustment dial in the front. The truck has turned into more of a daily driver now so my original plan is no longer in place. What I want from it now is just a nice, smooth ride. As it currently sits I feel every damn crack in the road. It just feels really stiff and it's not fun at all to drive. I'm not sure which tube(s) I need to adjust though to make it a softer ride.

 

tubes can only do so much to help the street ride. I would start by opening the both tubes all the way and see how it feels. If that makes it smooth on the street, then we can work on how to find a balance between the street and dirt. but if it doesnt help you have to change your valving.

For the front open the dial all the way and see if that helps. If not same as the rear we have to look at your valve stacks

 

Which ones though? I have three on the rear that I can adjust.

 

Sry, I assumed you knew about compression and rebound. So one tube should be labeled rebound and that controls when your wheel moves down. The other two tubes should be labeled compression and they controll when the wheel move up. Open all three all the way and then tell me if it gets smooth on the street.

But dont forget to record your current position so you can return it!

Starting from where they currently are, count how many turns it takes to fully close them. That will be your baseline. Then open them up all the way and report.

 

Okay, thanks. And no, I don't know shit about how adjusting the tubes affects ride. I've been reluctant to do anything for fear of really screwing up the ride.

 

If you can install the suspension, you can rebuild/revalve shocks.

 

Hey Alex, a list of tools might be helpful. I found it to be a bit of an investment. Lemme know if I miss anything.
1) Shock body clamps/ soft jaws
https://www.kartek.com/parts/king-fox-or-sway-a-way-30-shock-body-billet-aluminum-soft-jaws.html
2) N2 tank and fill kit
https://www.schmidtyracing.com/Uniweld-400PSI-Regulator-Kit-and-Whip-p/n-reg-uni400-8r-w.htm
3) Dust cap tool
https://www.kartek.com/parts/univer...per-cap-on-king-fox-or-sway-a-way-shocks.html
4) Reservoir piston tool
https://www.kartek.com/parts/all-ge...-depth-gauge-works-on-fox-or-king-shocks.html
5) Bullet
https://www.kartek.com/parts/fox-78...ls-from-tearing-when-you-rebuild-a-shock.html

The above are examples only, not suggestions. Different tools for different size/ brand of shocks. Research required, batteries not included.

 

Bro you bought bypasses and have never fucked with them?! Go to town! Sounds like your ride is already screwed up lol. Just screw the tube adjusters in and count how many turns they take and now you know where to reset them to. Bypasses work by flowing fluid around the piston in the zone that the tubes are mounted around. The tubes have a spring loaded check valve, by adjusting the screw you are adjusting how much that check valve can open. Since it's a check valve, it only allows flow in one direction. You can figure out the direction a tube works in by looking at the direction fluid can flow:



Looking at this picture, you can imagine the check valve on either of these tubes pointed up. If fluid flowed in from the perpendicular welded tube it would press against the back side of the check valve and keep it sealed, if fluid flowed in from the bent side direction it would push against the check valve and flow OUT (into the body) from the perpendicular side. So if you picture the shock compressing (piston moving up) it's trying to displace fluid, and that fluid can go in the bent side and out the perpendicular side and flow into the "vacuum" behind the piston. Likewise if you pulled the shock apart (rebounded it) then you get a pressure build up underneath the piston and it tries to flow fluid into the perpendicular side, but obviously the check valve now seals up so that tube won't flow. That's why tubes are rebound/compression specific.

So going back to what the tubes actually do, by adjusting the check valve you adjust the flow through the tube. So if you open up a tube completely then you are decreasing your damping since you are allowing lots of fluid to bypass (flow around) the piston. Likewise, taking it to the extreme, if you completely screw all your tubes in then your bypass tubes aren't doing anything and it's effectively a "normal" shock. This is also why a lot of times you see tubes that overlap the same section, tubes can only flow so much fluid (ie can only soften a zone so much). But on the flip side, the stiffest your shock can be is with no tubes in a zone. So you might have a really stiff shock, and a ton of tubes that overlap--all the overlapping tubes allow a lot of fluid to flow and soften the shock, but you still have super stiff valving for areas like the bump zone where you probably don't have any bypass tubes since you want it as stiff as possible.

This is why Oside said to open all your tubes, every tube open will make the shock as soft as possible. If the ride is still ass then the bypass and your coilover still have too much valving going on, even with everything set as soft as possible.

Hopes that helps a bit.

TL;DR -- Open (unscrewing) a tube makes that section SOFTER.

 

Thanks gents, makes sense. I have all next week off so I'll dick around with it on Monday and see where it goes. I'm assuming turning the adjusters clockwise (if you're looking at the face of the adjuster) is closing them up?

 

@osidepunker fix my shit.....





oh wait i need to do my 3" leafs first

 

Gotcha i will do this. I found a video of me doing some fake prerunner stuff. The terrain was alright. But from your expertise maybe you could kinda tell whats it doing. And how i explain how the suspension felt in mojave. This is a great topic that will help people that are far from shops that tune and shipping would be expensive. I forgot to mention am on stock leafs for now until funds allow to buy new ones.
https://www.instagram.com/p/BxXR-EXg94J/?igshid=hgj5p2eogimh

 

Image/Video isn't showing up for me.

 

Well that sucks. I tried uploading from my phone and it doesnt work.

 

haha no offense homie, but I dont see your suspension working. Need to get on some small whoops or terrain with more dips and rises

 

Some terrain like this would be a perfect testing area for an MT truck:

https://youtu.be/kryrpTcDzKU

Here is the best footage I have from when I was mid travel:

https://youtu.be/_R7DUbned4w

 

No offense taken this is on the east coast this as close i could get to lol Making the suspension work Ill try again in the future.