What diameter bypass

Fifty

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I’m trying to sort sizing, so I can then start planning location, of a bypass shock for the rear of my truck.

Truck is a deaver race pack rear leaf spring, around 18 inches of travel max, axle is a D46HD/m220 (so somewhere between a 44 and a 50 in weight, closer to a 44) wheel and tire combo each weigh 104#. The bypasses will be mounted almost vertical. Very little angled forward due to stuff. Unless I can get them to fit inside the new fiberglass bed sides on the outside of the frame. Then, if geometry benefits, I can angle them much more forward, but I don’t think that angle will actually help.

Truck weighs 5100# ish with gear, fluids and fatty. The f/r weight break down is really good and depending on gear location I’m pretty close to 50/50.

Use is high desert fun running, chasing guys that are way more serious, usually in their prerunners, others built raptors with ginormous everything but the wallet. Some runs are 2 hours straight no slowing, just hammering. Sometimes a little longer, sometimes a little shorter.

The front isn’t planned yet, that’s next. But I think it’s going to be a 14 inch travel at the wheel, using 10 inch travel 2.5 coilovers and 3.0 bypass’.

For the rear bypass, considering the weight, and the added work of the leaf spring, a 3.5 inch bypass was my original thought.

Any reason for dropping down to a 3.0 or going to a 4.0 (aside from buy as much as you can go?)
 

Bert is my name

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The extra fluid in the 4.0 will help with fade resistance. My buddy runs 4.0 on his ranger play truck. Not sure of the weight. As far as angle goes. Cycle the rear and see if the path of travel is going forward or towards the rear. As close to 90 degrees through the travel is the " optimal" setup. The rate of dampening will change with angle. 1to 1 ratio is the target.
 

Fifty

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I’m assuming the ranger/Tacoma etc are close to the same, being they are all the same “class” market/retail wise.

Buy once cry once. I already violated that rule once on this truck and it cost a bunch... lol
 

Bert is my name

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Go big. As time goes on you will probably be adding equipment, tools, spares. You can always take dampening out. You can only add so much before needing more shock.
 

Bert is my name

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I still have yet to see an argument stating why you couldn't lean the shocks toward the rear other than aesthetics. Theoretically the rear axle should move towards the rear of the truck in a leaf spring setup. Cycle ,Cycle,cycle. The path of the axle should dictate shock angle and placement. Supposedly angled forward helps with wheel hop ,but I would think proper shock angle would make valving selection and tuning easier. Proper spring setup should control wheel hop. I'm assuming that you are going spring under.
 

Bert is my name

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Too much shock angle allows the shock to rotate in the mounts instead of compressing the shock equating to uncontrolled wheel travel.
 

Fifty

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Yea. I already have the springs under from deaver. (Well it’s sitting in the bed of the truck at McNeil which I pick up tomorrow)
I saw them for about 30 seconds as they loaded them in the bed for me a few weeks ago. I wish I could tell you more about the specs. I just know they are for 350# of weight in the bed and a 1.5 inch of lift.... oh and for the bk spring under kit
 

Fifty

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Bypass should be at 90* at full bump correct? (Rear leaf)
 

Bert is my name

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Sorry for the short answer earlier. I was in class. If you imagine that the front half of the leaf is a link and the line between the front bolt and axle center line is that "link". Then your shock should be close to 90 degrees at bump.
 

gwizz

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I still have yet to see an argument stating why you couldn't lean the shocks toward the rear other than aesthetics. Theoretically the rear axle should move towards the rear of the truck in a leaf spring setup. Cycle ,Cycle,cycle. The path of the axle should dictate shock angle and placement. Supposedly angled forward helps with wheel hop ,but I would think proper shock angle would make valving selection and tuning easier. Proper spring setup should control wheel hop. I'm assuming that you are going spring under.
they actually cycle back as the suspension compresses. the front half of hte leaf spring acts similar to a link arm, the rear is all over the place cause of the shackle.



generally you want the shocks raked a bit forward. it adds a little bit of roll stablity vs strait up and down if you can spare the shaft travel. the axle hop deal is done by putting the shock forward of the axle, and for the axle to hop or twist it forces the shock to cycle, think of it like a "torq arm".

generally when i set up leafs i have the shock strait up and down at full droop. then at ride and as it cycles it rakes forward a bit.

a buggy dork front end is a great example of a shock with a falling rate, would be pretty hard to duplicate that unless you did it on purpose with rear leaf springs.
 
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