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Quick valving question

osidepunker

Well-Known Member
I don't know what tires you guys are running but those pressures seem to be really low. Most people that race are in the upper 30's or mid 30's. The lowest I have heard is 28 psi and that was with inner liners.

We plan to do some more testing before LDC on pressures but there is absolutely no way we could run 20-25psi. What am I missing?

Maybe you guys with pre runners are just not abusing wheels and tires like we do with race trucks?

Mike
Yes true, I'm not racing. I go hard, but not race truck hard. At 20 psi, my sidewall holds ride height but still flexes over rocks. It does pretty well in soft sand too. On really big hits the tire does collapse, but I'm ok with that for the most part. I have bent a few rims, but only a few over the last 4 years. Main thing is the ride is nice and comfortable LOL

37x17 here too. I guess I'm thinking that it's cheaper to run a little more tire pressure then bend a rim haha. I do carry 2 spares so I could play around with less pressure and get home if I lose one. I'm just not sure it's a good idea with the type of terrain I'm running in. It's super rocky and sometimes I'll get up to 60-70 mph.
Yes its possible to bend a rim at lower pressures, but like I said, it hasn't been a big deal for me. Also, I'm not doing 60-70 mph over rocky sht haha if you're doing that then definitely run more pressure
 

chatter_splatter

Well-Known Member
Yes true, I'm not racing. I go hard, but not race truck hard. At 20 psi, my sidewall holds ride height but still flexes over rocks. It does pretty well in soft sand too. On really big hits the tire does collapse, but I'm ok with that for the most part. I have bent a few rims, but only a few over the last 4 years. Main thing is the ride is nice and comfortable LOL



Yes its possible to bend a rim at lower pressures, but like I said, it hasn't been a big deal for me. Also, I'm not doing 60-70 mph over rocky sht haha if you're doing that then definitely run more pressure
All of my other rigs I've run down in the 15-20 psi range, but the fastest I would typically go was 35-40. More speed needs more rim protection and even 25 psi is barely enough with this truck driving at speed. Any "oh sht" hits and the lug wrench and jack are coming out. I've already done it once. Burped a bead and got some dg between the tire and rim. That's when I figured out the 16" spare wheels that were on the truck won't fit over the calipers up front. I carry full size spares and run at 30psi now and haven't had any issues yet. It's just not as plush as it could be.
 

chatter_splatter

Well-Known Member
Update: Got my bypasses back from Fox. They did a fantastic job and the customer service was great!

Snapchat-1365989413.jpg


Put them on with the comp tubes open and the harshness problem was gone. Got them pretty dialed now, truck works great.

Adding the short compression tube along with more room between the compression stack and topout washer in the coilover solved the problem.

Of course now that the truck can go faster, I have a new set of tuning problems to deal with, but I think I've learned enough from you guys that I can handle it.

I've talked to enough professionals to realize that this stuff is very complicated and advice almost never comes free. I understand why. Shock tuning takes hours of work to learn, and when someone invests the time it takes to get good, it doesn't make sense to give that experience away for free.

I want to thank all of you for the time that you took to explain to me what took you years of experience to learn. I appreciate it, and will do my best to contribute what I can back to the community.

Videos coming soon!

-Will
 

osidepunker

Well-Known Member
Those look good! Yeah I'm starting to realize the tubes can only flow so much. I can actually feel when the flow is being restricted by the tubes as the valve stacks get heavy. Having an additional tube would really open up the flow. My stacks are so big in the front that if I close the long tube too much, even though the short tube is fully open I can feel it getting harsh. I have to use the flow in both tubes to keep it smooth. A 3rd tube would help, but I'm not ready for that yet
 

chatter_splatter

Well-Known Member
Those look good! Yeah I'm starting to realize the tubes can only flow so much. I can actually feel when the flow is being restricted by the tubes as the valve stacks get heavy. Having an additional tube would really open up the flow. My stacks are so big in the front that if I close the long tube too much, even though the short tube is fully open I can feel it getting harsh. I have to use the flow in both tubes to keep it smooth. A 3rd tube would help, but I'm not ready for that yet
Mine started getting harsh with the short tube open all the way and the long tube open 6 turns. Only had a 2,1 stack in it though. Trying a 3,3,2 next to see what happens.
 

osidepunker

Well-Known Member
well my truck is a lot heavier, but I have a 4.3.2 all 20s. With long at 2 turns and short at 1 turn its not harsh. I opened long to 3 turns (which is basically wide open) and short to 1/2 turn and it started getting a little harsh. so 2 and 1 is the sweet spot as far as the little stuff goes.
 

chatter_splatter

Well-Known Member
Wow maybe we have different poppets? Mine are tapered so the adjustment may be different. My tubes don't flow a whole lot at only 1-2 turns open.
 

chatter_splatter

Well-Known Member
Another thing I tried is the Gold valve on the short tube. I like it a lot. Basically turns the short tube into a comp/rebound tube so the suspension can drop out really fast, but then the primary rebound tube can be tightened up to stop the truck from pogoing when it compresses more than 3". Kartek has them for $30.
 

chatter_splatter

Well-Known Member
So you got the front dialed and now your going fast enough to realize the rear sucks?
Yeah that pretty much sums it up. Not enough travel. Not enough stages in the bypass. Bump stops are too tall and they are seized in the cans.

Trying to just keep the front stiff so it stays nose high for now. Have 3,3,2 in the front bypass with fast rebound.

Maybe links someday.
 

chatter_splatter

Well-Known Member
Your rear bumps are not to tall, they are just set-up wrong.
They are 4" stroke and only sit 3" off the bump pad. I've tried a few different pressures and oil levels. What works best is filling the bumps with oil when they are fully compressed, then charging them to 100psi. More pressure and it kicks. But it's still not enough to prevent it from bottoming hard.

I would like to try shortening them but I'm not sure I can without removing them from the can.
 

cosmo

Super Moderator
Wow maybe we have different poppets? Mine are tapered so the adjustment may be different. My tubes don't flow a whole lot at only 1-2 turns open.
With only one or two turns open ( from closed?) of course there is not much flow! Try, 4 to 6 turns open, from fully closed.
 

chatter_splatter

Well-Known Member
With only one or two turns open ( from closed?) of course there is not much flow! Try, 4 to 6 turns open, from fully closed.
That's what I thought too. Oside said that his short tube is open 1 turn and his long tube is open 2 turns with a 4,3,2 compression stack. All 20s.

Oside did you say you have a flutter in the BP?
 

osidepunker

Well-Known Member
With only one or two turns open ( from closed?) of course there is not much flow! Try, 4 to 6 turns open, from fully closed.
That's what I thought too. Oside said that his short tube is open 1 turn and his long tube is open 2 turns with a 4,3,2 compression stack. All 20s.

Oside did you say you have a flutter in the BP?
That's backwards.
yeah backwards. For the front, I have short course pistons, 4.3.2 all 20s, no flutter. My short tube is open 2.5 turns, long tube is now at 3/4 turn. I have tapered fox poppets. What I have found is that max flow is about 3 turns. I dont feel any difference when I open them up more than that. My bypasses are basically bumps and I am controlling most of the stroke with the coilovers. I have revalved 5 different times and I think I have them pretty much perfect:

1.800 0.010 x1
0.800 0.020 x1
1.800 0.010 x1
1.600 0.015 x1
1.425 0.020 x1
1.350 0.020 x1
1.100 0.020 x1
0.950 0.020 x1
0.800 0.008 x1
1.800 0.015 x1


Another thing I have learned is that Fox tubes can only flow so much. They overlap so more tubes equals more possible flow. Not sure about other shocks, but Fox tubes have to work with the valve stacks. For example, I have my coilover controlling all my rebound (#90). I had a #90 in the bypass, but I had the tube wide open. My thought was I would add a little rebound control with the tube if the coilover wasnt enough. But I had enough so I left it open. Well, I had been noticing that I was getting a "bounce" on the road and after a while I came to the conclusion that it was due to too much rebound. So last Fri as an experiment, I changed the rebound stack in the bypass from a #90 to a #40. This completely eliminated the weird rebound bounce I was getting. So my conclusion is that my wide open rebound tube combined with a stack that was too big was not flowing enough at slow speeds.

In the rear I have short course pistons, single flutter/20 fulcrum then a 3.2.2 stack. The short tube is open 2 turns, long at 1/2 turn. 17" travel with 3" bumps at 225psi. I have 5" before I contact the bumps, so 8" total uptravel. I had to do some work on my rebound, I went from a #70 to a #80 and initially at 1 turn open I was bucking and kicking and I couldnt figure it out. Someone told me I was "all locked up" and I had to open my rebound so I went to 3 turns open and all of a sudden my rear calmed down haha So I will probably go to a #75 in order to get to the middle of the range of adjustment for my rebound tube.
 

osidepunker

Well-Known Member
Dont forget my truck is heavy, 8000 lbs with 50/50 weight distribution. I had to get creative with my stacks/pistons
 

chatter_splatter

Well-Known Member
Dont forget my truck is heavy, 8000 lbs with 50/50 weight distribution. I had to get creative with my stacks/pistons
Sometimes what works doesn't make sense! Every truck is different. I'm fighting some bucking problems in the rear because I don't have enough up travel. I'm thinking about shortening my shackle or shortening my bumps. The front of the truck does great, but sharp lips at high speed compress the front further then the rear is capable of compressing and the high spring rate from the bumps bottoming pushes the rear up. Stiffening the compression up on the front helps but it doesn't eliminate the problem. The stiffest I can comfortably go on the front bypass is short tube full open, long tube 4 turns open. Any tighter and the valving starts working on the bypass and causing harshness. The most comfortable setting is short tube full open, long tube open 6 turns. If I had more uptravel in the rear it wouldn't be an issue, but if the front of the truck doesn't pop enough, the rear can't keep up.
 

chatter_splatter

Well-Known Member
Ok so here are the numbers. Rear uptravel is only 6" and 4" of that travel is bump stop. Bumps are only 2" away from bump pads at ride height. Shackle is 8 long. Droop is 10" and rear axle weight is 2500lbs. Springs are Deaver F87.

How do I fix this? Are the springs sagging that badly? Am I carrying too much weight?

I noticed the anti friction pads all fell off. Would putting new ones on add some ride height?

Would shortening the shackle to 6" or even 4" put me at risk of over arching the spring and breaking it? They already go into about 2" of positive arch.

The rear of the truck just doesn't work well with so little uptravel. It kicks off of just about everything.

Any ideas?
 
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