Number of Bypass tubes, leaf sprung

Fifty

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Technically one could always argue more is better... but sometimes less is more.

Is there a decent rule of thumb so to speak about the number of bypass tubes, both compression and rebound, for a certain amount of suspension travel?

For instance, I am about to measure the travel on a spring under conversion and I believe it should be 16-18 inches.

There is a bit of a premium on space so mounting will be just forward of vertical. Maybe 15-20* angled forward. I’m assuming at this point it will be an 18 inch travel 3.0 or if I can fit it, 3.5 inch diameter bypass.
I’m also running a bump shock.

Since I won’t be using the bypass as a bump, is a 4 tube as far as I want to go? Or will a 5 tube with a 3/2 split compression/rebound or since I have the bump a 3/2 split rebound/compression?

And lastly, is it just too muddied with that little travel and to stick with the 4 tube.

It seems the places I drive are more hard packed and with either tons of wash board or whoops that swallow my current set up.

I don’t really seem to find mild to moderate bumps.
I had figured on trying to focus on the small wash board tuning, then have something for the mid travel and then enough adjustability for any big hits over and over...
Hence the consideration of the few extra bucks for the 5 tube.
 

Bert is my name

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Tube placement is just as important as number of tubes and adjustment. Giant motorsports gets away with two tubes on their link killer setup. That kit works extremely well. I would talk with the shock manufacturer and with deaver about tube number and placement. I'm all for adjustability but sometimes too much leads to confusion. I think for your application fewer tubes may lead to more enjoyment. Meaning less time messing with adjustments and more time driving. Remember leaf springs are progressive and have some dampening ability built into them. The extra tubes may end up being an unnecessary expense and one more part to fail.
 

Fifty

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I’m still trying to figure out Giants little shock on the rear axle connecting to the link.

But I hear you on the keep it simple stupid.
 

Bert is my name

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That's the daily driver link kit. The link killer is a leaf spring setup that cycles link type wheel travel numbers. 64 inch dealers built to there spec with king two tube bypasses also built to giants specs. It works really well. Rides as nice as some of the linked trucks I've been in.
 

Fifty

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I guess Im trying to figure out how that pivot works with that little shock. Does it just eat up the small bumps like washboard?
 

KTB Racing

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I have 3.0 x 18” Kings with the “Link Killer” layout. Its only 2 tubes and the compression tube is larger than what would be standard on a 3.0 bypass and it is almost as long as the shock body with a 4” bump zone. I don’t think more tubes or a larger shock than a 3.0 are much of a benefit on a leaf spring trucks, especially if you arent going to be racing. I think you would see better performance with as much weight as possible behind the axle. And tuning for washboard roads can be done with the internal valving.
 

partybarge_pilot

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2 comp tubes with the "Fox" layout and 1 rebound. With a 3.0 you may even want a bleed hole in the short com tube poppet. If you get the standard King layout you will need them in both comp tubes.
 

Fifty

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When I think about sizing, I think about the runs I do with the group I’ve been going with. They have significantly built trucks. The lowest built truck (outside of mine) is the furthest I will build my truck.
Many are linked, many are test vehicles for some of the commercially available prerunner kits out there (no one is making anything realistic for my chassis yet so it’s just me trying to figure out something one off).

These trucks, albeit are about 500-800# heavier in the front and running 37’s, 39’s and 40’s (a few are on 35’s) so that weight difference variable is there.

Anyways, I have been watching a lot of the progression of these trucks components between runs based upon what has occurred. (I wish I had the money to throw like these guys...)

There is one truck for instance that was on a 2.5 c/o front and 3.0 bypass leaf rear with rear 2.5 bumps.
It then went to 2.5 c/o 3.0 bypass up front and 3.0 bypass rear. Then 3.5 bypass rear. Then bumps up front too, now 4.0 bypass rear.
Now the driver is a little crazier than I and has an extra hundred hp, and a heavier truck.
But that’s the progression that truck has made when it comes to controlling heat and the weight.

I wish I had the funds to take these steps. But I don’t. I need to learn from their mistakes and testing and try to start as close to my goal as possible.
I am lucky, that I’m using a lighter vehicle, lighter tire wheel combo, I’m a little older and broken so I drive a little slower sometimes...sometimes.

But at the end of the day, this truck does have a license plate, but it’s an off-road toy. So I’m focusing on not compromising for daily driving (that is a topic that I have had a real hard time explaining... or rather getting fabricators to understand). I’ve spoken to 3 and when discussing the project each would regress and say “we will do this so when your daily driving...”.

It would then take another 10 mins of discussion explaining the situation of the trucks use.
At which they would change the plan back to the original focus of geometry and build characteristics that were more focused for dirt and not cement...
Then repeat.

Very frustrating and didn’t leave confidence in the project going the direction I was looking for.

Long story short, I really appreciate everyone’s opinion and reasoning.

I have to balance my desire for Gucci gear overly complicated, will never be used or benefitted from parts and design, vs “KISS” this is the better way to focus the funds and spend less money here and more money there.

Aka less on Gucci extra large bypasses with 5 tubes and more on an external trans cooler...

Sorry I was going to write more and clarify but kid is bugging me
 

partybarge_pilot

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And tuning for washboard roads can be done with the internal valving.

Not if your running a single BP. Bleed should not be done in the piston, it should be done in the poppets or your bump zone will suffer. You will need a fair amount of bleed with a leaf sprung truck.
 

Bert is my name

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What i dont get is the fabricators focusing on dirt when you tell them it's dual purpose. If the geometry is correct and the truck is balanced it should handle well on the street. Circle track magazine ran an article about 15 years ago talking about soft springs and big sway bars. It made a lot of sense. Instead of controlling body roll with stiffer springs the theory is to run just enough spring to set ride height and throw a big a$$ sway bar in to level the vehicle out. I think applying this to your truck will work well. When you hit the dirt disconnect or swap bars.
 

Fifty

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What i dont get is the fabricators focusing on dirt when you tell them it's dual purpose. If the geometry is correct and the truck is balanced it should handle well on the street.

And if I was smart enough in the world of Offroad geometry, I’d design it all myself and cad it, laser cut it, weld her up and order some shocks and bobs yur uncle!!! Lol!

As I was typing I was trying to remember what topics the fabricators were talking about compromising for street vs Offroad.

-One bit was definitely a single free bleed compression only vs both compression and rebound bypasses.

-Another was leaf spring design and not going through the bed for longer bypasses our back.

-I remember another, now, about the front control arm designed to move the knuckle forward for a bit more tire to fender/firewall clearance. It was a “leave the hub where it is, set the bump stop to eliminate compression to allow enough clearance when turning under compression” and some other bits and pieces... (that one was one shop alone)

-Single 2.5 8 inch travel c/o up front, no bypass, using the stock upper shock mount.

As for handling on the street, I agree. It may be a little softer here or there. But if I wanted a Porsche handling on the street, I’d drive a sports car.

(I drive a Honda Element if I’m not ferrying the kid around in the suburban. I’m not sure my wife will allow me a sports car anymore... something about a house husband not needing a sports car. I tuned her out.)
 

partybarge_pilot

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soft springs and big sway bars.

That is a horrible idea. The sway bar is basically an undamped spring. Valve to take that into account and it would screw up your strait line performance. Don't valve for it and you will get some serious whip in cross grain. Dirt track cars are do not see the same terrain that off road cars do, many things do not cross over.

Don't fear the lean, it will handle just fine on the street as long as you don't mind a little 3 wheeled action.
 
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