Dlux Berg Build

[Erik D_lux]

Originally Posted by Shaunkjar

If you were out running a desert truck across whoops and nasty washboards,....

I have actually done quite a bit of shock tuning on a 1:1. Problem is that I did just like youre saying. I tuned mostly for going fast in the whoops and then I would not change anything unless I was say, on a climb and the rear was bouncing a lot. Then I would adjust the rear. Mostly what I tuned for was going fast though...

I just looked at my sheet for my 1:1 as I kept all records. Looks like I ended up front being a bit stiffer on compression and rear a bit stiffer on rebound. Again, I dont think it means much though, I tuned the crap out of those shocks and they were singing by the time I was done but, I only know they were doing well in the go fast, I THOUGHT I had them pretty good for crawling too but, I really dont think you can fine tune a 1:1 nearly as well as you can a RC crawler. Can you imagine getting out of your 1:1 and moving your front shocks 1" in either direction just to see how the change feels and then driving up some hair ball obstacle just to roll over back wards from 12 feet high?

Originally Posted by TheSCorpionKing

Slower compression and faster rebound would definitely cause the truck to bounce more upon impact and cause severe unloading making the hop even worse.

Did you watch my video? I think the video shows the opposite and I definitely felt the opposite of what youre saying....

Originally Posted by Harvo

Cool experiments. I know more about mountain bike shocks and suspensions than crawler shocks, but I think some of the principles apply. It would be nice if crawler shocks were externally adjustable like the ones on my bike (there's your next projet Erik)

I was just saying that. I need external bypass shocks on this puppy.


Interesting to see everybody's input on what they do and what they think. It really makes me see other things and opens my mind for sure.

[markfw]

Interesting to see everybody's input on what they do and what they think. It really makes me see other things and opens my mind for sure

You having an open mind to other peoples opinions is what makes you a great vendor in our sport!

[TSK]

Sorry. Didn't ge a chance to watch the video yet. Been running around all day. I'll check it out in an hour or so and revise my opinion.

[Erik D_lux]

Originally Posted by markfw

You having an open mind to other peoples opinions is what makes you a great vendor in our sport!

Thanks Mark!

If anything, it makes me laugh. So many people I respect and think are "smart" people and in the end, "All roads lead to Rome".

Originally Posted by TheSCorpionKing

Sorry. Didn't ge a chance to watch the video yet. Been running around all day. I'll check it out in an hour or so and revise my opinion.

No need to revise your opinion unless you see differently. I can respect your opinion if its what you believe.

My thinking right now is that there is desert racing shock tuning and whatever shock tuning you RC go fast people do. I am guessing that crawling shock tuning would be in a world of its own. Going over a whoop and trying to keep your front down on a climb seem like they would be worlds apart to me. In fact, if you think of it, I know in desert racing youre always trying to keep your front up, kinda like a wheelie. In crawling, I think you want the opposite, always having your front as down as possible, rear wheelie if you will.

[TSK]

So in the video, the pistons were arranged so that the compression will be faster than the rebound? It does make sense that the thicker oils would exhibit more sensitivity to the valving changes, especially when the valve stack is closed.

In my mind, I still believe fronts w/ fast compression slow rebound is the way to go. And on the rear I believe slow compression and fast rebound would be better. I imagine that it would provide for the least amount of rear weight shift.

I seems like tuning for go fast and crawling would be worlds apart, but the physics behind it all is constant. What needs to be realized is that the 1:1 tuning won't correlate to the 1:10th scale. A 1:1 crawler has an extreme amount of sprung mass both high up and far forward (engine & transmission), whereas rc comp moa trucks have a lot of unsprung mass down low in the axles. I have a cockamamie hunch that a rc crawler needs to have it's suspension tuned in respect to it's affect on the opposite axle (front suspension tuned in regards to what it does to the rear axle) as opposed to tuning suspension relative to what the chassis does relative to suspension action.

[Erik D_lux]

Originally Posted by TheSCorpionKing

So in the video, the pistons were arranged so that the compression will be faster than the rebound?

The way the instructions tell you to build the shock is with the valve stack on top so, compression was slower than rebound in the videos.

[TSK]

Originally Posted by Erik D_lux

The way the instructions tell you to build the shock is with the valve stack on top so, compression was slower than rebound in the videos.

You followed instructions?

The picture of it I found on the interweb showed the flapper valve on the bottom of the piston.

If I were you, I'd try tuning a bit more extreme. Like go with the fast stack and 90wt. Then on the next run, just flip the piston stack. That would give you a far better idea as to which direction to head. I would probably do just the fronts with a standard piston in the rear first. I'm a fan of going far out and dialing back in as opposed to taking baby steps out to the limit.

[Erik D_lux]

Their directions were all over the place for different types of shocks. For the Big bore, you just take the stock stuff off then piston, valve stack (single, not many).

Yeah, there is lots of testing to do. I felt like the fronts were an instant improvement over what I was running. After running it and changing oils and faster valve shim, I know its better than stock but not positive that its perfect yet. The rears is where I am moving now. They were instantly horrible and I could not get them to feel good at all. I maybe going back to stock in the rear if I cant figure something out.

[TSK]

I really think you should try flipped the stack in the fronts. At least for prosperity's sake. The changes to the rear did appear to have a horrible affect on things. I guess I was definitely wrong on the slow compression fast rebound on the rear.

[Erik D_lux]

Originally Posted by TheSCorpionKing

I guess I was definitely wrong on the slow compression fast rebound on the rear.

I dont know if I would go that far yet. Maybe it needed 100wt oil? Thats the toughest part of this situation right now, I dont even know what ballpark is.

[TSK]

Originally Posted by Erik D_lux

I dont know if I would go that far yet. Maybe it needed 100wt oil? Thats the toughest part of this situation right now, I dont even know what ballpark is.

Yeah I can't be THAT wrong. Lol. Too many factors to consider now. You better stock up on some Excedrin.

[stubs179]

I just don't see your shocks being a factor with hopping or really anything that deals with vertical travel of the chassis? Your chassis with elec. can't account for more than 7% of your rigs weight so I can't see the shocks moving vertically when the tires hit a bump.

In the video your shock look locked out while on the climb. But with the setup you said you thought felt the best it looks like the front settles in better? Flexing with little or no weight on the front?

Since climbing is where you will benefit the most and your front shocks are topped out on climbs, I would try a softer compression (because that seams to let your front axle soak up the little spine better in the video) and stiffer compression to help control the rig on flatter obstacles where you what to slow the flexing down a bit. That's what I would try anyway?

[SkaldidDog]

Originally Posted by Erik D_lux

I would say that the contents of the shocks change the way the car reacts though.

If you watched the video,...

If you have an idea for a better way to test, I would love to hear it. How did you come to the conclusion that what youre running is the best for you?

I agree, but more with regards to truck movements that cycle the shocks.

I watched your entire video and now I want to come drive out there even more.

My testing is far more basic. More below.

Originally Posted by Harvo

On my crawler I try to tune all the hopping out with my tires and foam. All I need the shocks for on climbs is to make sure they stay in contact over irregularities in the climb.

This is the flag I'm waving.

Originally Posted by stubs179

I just don't see your shocks being a factor with hopping or really anything that deals with vertical travel of the chassis?

Kinda like Stubs says.

Regarding how I tune shocks. I run the same springs on all four corners with the same pre load, just slightly different shock angles. I really have't put much thought into it. I think I'm running 25/30 F/R (don't quote me as BB's never need attention so it's been a long time) with three hole pistons. Regarding hopping, I think it's all in the tire/foam like Harvo said. We may be wrong. My tuning process is just to change the shocks and drive it for ten packs repeatedly covering as many different "resolution points" as I call them, and consider what I've seen. Since tuning is give and take I don't focus on how my rig does one obstacle after a change, but on many obtsacles that put the rig through it's paces. The final test is the twist-it-in-my-hand test. I can tell a lot about a rig with a little molestation. Just a few variable speed twists tells me a lot about whether I'll like a new shock setup or not.

[Erik D_lux]

Originally Posted by stubs179

I just don't see your shocks being a factor with hopping or really anything that deals with vertical travel of the chassis? Your chassis with elec. can't account for more than 7% of your rigs weight so I can't see the shocks moving vertically when the tires hit a bump.

I dont know how you can say that the shocks could not be a factor. Have you ever tried a really heavy weight and then a really light weight in your shocks and done the same climb (without the shock being half full of air STUBS! )? I know it looks like they lock out and do nothing but its dramatically different. I think even watching the video, its obvious that the "ride quality" changes from one setup to the next. Maybe thats just because I have a good idea of how the car felt?

Originally Posted by stubs179

I would try a softer compression...and stiffer compression to help control the rig on flatter obstacles

Which one did you mean to say "rebound"?

Originally Posted by SkaldidDog

This is the flag I'm waving.

I think we are all talking about the same thing but using different words.

I use my foam to tune also, but there is give and take with it as with everything. If you wanted the best climbing setup at this place, you might not even use foam. Rover foam in my Sedonas once I went under 5lb was really, really too stiff. You know how soft my foams used to be.

"stay in contact over irregularities in the climb"

In my words, that means no hop. The way to get the most traction is for your tires to never leave the ground and always say in contact over irregularities. I have driven a lot out at this place and like I said, its not a spot that you want to show up if you have not put time into your car. It will bring out the worst in it. I have done a lot of oil changes here. What I have found is that I really want to run say a 60wt oil as it keeps my tires in contact with the ground much more. I cant go that high though because my rig will not cycle fast enough on other spots where my car needs to articulate. It will also not soak up bumps. I have always errored to the side of a heavier weight as it suits my driving style more (aggressive) but I know I have always struggled on bumps because of this. This is where I hope these bypass pistons come in. I hope to get my firm and planted feeling of the 60wt but it can move out of the way when I need to bump something. Whether or not this is possible is the question.

Originally Posted by SkaldidDog

Kinda like Stubs says.

I guess I dont understand how you guys can think that the shocks do nothing when they are fully locked out. Some guys in our club dont run shock oil because they say it will just leak out eventually anyway. Watching these guys on a climb is painful and I know for a fact that its because there is no oil in the shocks. If you dont think your shocks are doing anything when they look locked out, I would suggest that you take your pistons off the shocks and try and do a climb. You will see that it is indeed doing something significant. I suppose that it could be less or more though depending on the amount of squat and anti squat you run. If you ran a large amount of anti squat in the back and the rear was extremely locked out, you should see less of a change?

Originally Posted by SkaldidDog

My tuning process is just to change the shocks and drive it for ten packs repeatedly covering as many different "resolution points" as I call them, and consider what I've seen. Since tuning is give and take I don't focus on how my rig does one obstacle after a change, but on many obtsacles that put the rig through it's paces. The final test is the twist-it-in-my-hand test. I can tell a lot about a rig with a little molestation.

Just to be clear, I am not tuning to this one obstacle. The video I took was just so I could go back and watch. I think our memories can skew reality, thats why I also immediately wrote down how I "felt". Now I can take the visual from the video and my feelings and try to figure out an initial setting. Once I have this initial setting, I can now drive my car and observe many other situation and see how it reacts. Like I told TSK above, I am not sure if I need 10wt and the lightest valve stack or if I need 100wt and the heaviest valve stack, to have rebound lighter or heavier than compression or anywhere in between. I was totally lost on a starting point so thats all the video and that test was for, a starting point. If you simply put in 30wt and a medium valve stack it could be completely different than what you need and it would not serve me to give a thumbs up or down on the system when I dont know if I am even in the range I need to be.

Originally Posted by SkaldidDog

Just a few variable speed twists tells me a lot about whether I'll like a new shock setup or not.

I would love for you to do that to my car now. It feels crazy with the different rebound/compression and I just flipped my valve stack in the rear so the car compresses and rebounds really strange.

[TSK]

I think what Stubs is trying to say he would want faster compression in certain situations and slower compression in another.

I a RC crawler suspension is maybe 5-10% for soaking up bumps/wheel hop amd 90-95% for contorling the rate of loading/unloading during articulation, which points back to my earlier statement about how I think you need to tune you front suspebsion relative to how it affect what your rear axle is doing 9and vice versa). Shocks with no oil have zero damping and therefore zero control of the rate at which the suspension articulates which is why it looks painful to watch, Kinda like seeing a lowrider with hydraulics on a pot hole riddled street. the lack of damping just results in uncontrolled body movement. But since the RC crawlers has such low sprung weight, the axles react in an unp[redictable manner. Having oil in them with appropriate valving keeps this uncontrolled movent in check.

I'd think, this experiment would be easier if the closed stack valving of the MIP pistons where the same as say the stock 3 hole piston on the BB. Then you could run your standard oil/spring combo and basically just speed up your compression or rebound while keeping the other motion the same as your standard setup. Because the valving is not the same, you really are just having a crap shoot in regards to finding what is comfortable.

I'd suggest you try removing the shim abd finding a good oil for the valving of the unshimmed piston, and then start playing with the shims and stack orientation.

[stubs179]

Stiffer rebound, softer compression. I've done a fair share of shock tuning but it was on dirtbikes. I think of rebound more as how much your allowing the the chassis to push away from the tire not how fast your allowing the tire to move down.

I have my anti-squat very neutral? No matter how steep the climb my shocks sit about mid travel on climbs. I have never noticed my shocks cycling even a little when hopping.


In your vid I think it was the third setup? Around 1:50? Your front looks like it settles in the best to the spine on the left and the little nub on the right. With the setups that have thicker oil the left front lifts when the right tire hits the little nub but with the 3rd setup it doesn't pull the left tire thus keeping traction on all 4 tires. And your front shocks look topped out on that climb. So when the front tire hits the nub it's all in how well your right front and left rear shock absorb the impact.

The only way I think you would be able to test what your looking for is on a very even steep surface. Because the amount and how your axles are flexing on that climb have a huge impact on your progress to the top.

[TSK]

Originally Posted by stubs179

I think of rebound more as how much your allowing the the chassis to push away from the tire not how fast your allowing the tire to move down.

[SkaldidDog]

Originally Posted by Erik D_lux

I would love for you to do that to my car now. It feels crazy with the different rebound/compression and I just flipped my valve stack in the rear so the car compresses and rebounds really strange.

I bet it does feel really different. I'll find you when I get to AZ to check it out. I know similar valves make a big difference in my eRevo GTR shocks but that's all fast bumpy fun.

Keep researching this man. Genius starts out as crazy or eccentric.

J

[Harvo]

The irregularities in the rock start the hopping. The way the tires squish, grab, and rebound is what keeps the bounce going. If you can tune the shocks to soak up the irregularities it should keep the tires in contact. If they do lose contact... the perfect tire/foam combo will pick up the task from there.

That is why I like pin tires. They will bounce, but it takes a lot more to make it happen. The bounce frequency is quicker too so you can get it back under control without loosing much ground. Big lugged tires have a slow bounce frequency and for every hop they move back down the climb further, creating more squish and more tire rebound.

The shocks will compress and rebound on every hop... but IMO you will drive yourself nuts trying to get rid of that behavior with shocks.

BTW... were your batteries pooping out in any of the videos that were labeled bad? Because tire speed is a factor too. Just curious.

[Curcal]

Travis had a good thought about tuning one axle towards the other. I found this to be true when i was externally limiting my shocks. As I was aiming for the perfect limit I went long in the front and small in the rear. I noticed the total travel was a combination of shock movement in diagonal corners. For a neutral set up I added the total amount limited and split the sum between shocks on the diagonal.

Moral of the story: (I think) front and rear suspension are more interrelated than we might think. You tuned front shocks to give you the perfect feel. After achieving the feel you decided to start tuning the rear. Which in turn changes the way the front reacts.

To be scientific: you should reset you front shocks back to 30wt no pack and try and tune the rear to your liking. Then try to figure out how to split the difference between front and rear.

I may be way off base, but it seems fairly logical.