Truck bouncing under power

P

pxcr440

New member
Have a 2.6 smooth 3rd gen qcsb solid rear no springs, blocked up front ,1200 or so hanging up front locked front and spooled rear .truck can blow tires off out of hole and soon as traction comes it starts to bounce. Roll out half throttle it's fine soon as full throttle it starts to bounce , fresh control arms, t steering. New real wheels with general grabbers ,fronts tried from 20 to 35 lbs same result. Rears at 55.

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It's not my truck just helping in it , set up same as last 3 trucks I have done with no issues,, it hasn't gone more then 100 ft before he lets out cause of bounce

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Looks like it isn't hooking up enough to ever lift the front off the stops, so it is just bouncing. I would lower the front stops.
 
Alright. That's what we did 2 inches see what it does tomarrow ,I knew the height may be a problem and not having any preload left on springs, between the 2 inch backspace front wheels and tires and longer control arms clearance is tight. I chose coilovers in my stock springs on mine to help get front up

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pxcr440 said:
Alright. That's what we did 2 inches see what it does tomarrow ,I knew the height may be a problem and not having any preload left on springs, between the 2 inch backspace front wheels and tires and longer control arms clearance is tight. I chose coilovers in my stock springs on mine to help get front up

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I agree with Jeremy, too much preload up front. 2" is a lot with anything that is rigid in the rear and has weight hanging. It's bouncing the front tires.

I
 
jones95runner said:
I agree with Jeremy, too much preload up front. 2" is a lot with anything that is rigid in the rear and has weight hanging. It's bouncing the front tires.

I
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So were on same page ,, agreeing there's too much weight still on axle directly and not enough sprung weight on springs

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pxcr440 said:
So were on same page ,, agreeing there's too much weight still on axle directly and not enough sprung weight on springs

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Only thing change from last year up front was 3/4 space over last year's block and 400lbs extra in box ,, but did go from reese style at 44 inches to a draw bar for rules so likely where we lost lift as Last year it never bounced a bit

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pxcr440 said:
So were on same page ,, agreeing there's too much weight still on axle directly and not enough sprung weight on springs

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pxcr440 said:
Only thing change from last year up front was 3/4 space over last year's block and 400lbs extra in box ,, but did go from reese style at 44 inches to a draw bar for rules so likely where we lost lift as Last year it never bounced a bit

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Yes. There is to much weight on the stops. The truck isn't transferring enough weight to the rear to lift off the stops and the front tires are becoming the springs with no shock to control them and causing the bounce. I would run the stops down to where they barely touch. We used to take 700 pounds out out of the box and set the stops till they barley touched then put the weight back in but from your video I don't think that would work for you unless you have the stops just way too high to begin with. The extra 400 pounds is what's upset the truck
 
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DISTURBED said:
Yes. There is to much weight on the stops. The truck isn't transferring enough weight to the rear to lift off the stops and the front tires are becoming the springs with no shock to control them and causing the bounce. I would run the stops down to where they barely touch. We used to take 700 pounds out out of the box and set the stops till they barley touched then put the weight back in but from your video I don't think that would work for you unless you have the stops just way too high to begin with. The extra 400 pounds is what's upset the truck
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Ok thanks guys,, same thinking we had ,just wanted more input will se how today goes

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pxcr440 said:
Lowered front truck hooks smooth now

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Good deal!! If you need or want to run the front stops, I would start by running them up till they touch the adding a turn to them to start. When I built my truck originally I watch a lot of videos of it running and would measure the mirror on it (for reference since I know the mirror was x inches tall) and then the distance between the top of the front tire and the bottom of the fender to see how much it lifted. I set the stops a half inch below that. That's where the truck wants to run.
 
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DISTURBED said:
Good deal!! If you need or want to run the front stops, I would start by running them up till they touch the adding a turn to them to start. When I built my truck originally I watch a lot of videos of it running and would measure the mirror on it (for reference since I know the mirror was x inches tall) and then the distance between the top of the front tire and the bottom of the fender to see how much it lifted. I set the stops a half inch below that. That's where the truck wants to run.
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I watched videos and eyeballed the distance between the top of the tire and the fender. It is a little bit of a balancing act if you run lots of varying track conditions. I could tell on loose tracks I would be really close on the stops as the truck would want to bounce a touch. Also I left the rubber in and let the truck have a little give and not be a "hard stop"
 
This one has to have blocks, and springs seem soft, no block at all results in track bar bracket setting on diff and edge of spring bucket. Like to see front back up and add needed spring rate. For now tho just wants to leave it and get some hooks

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This post has got me thinking about trying front stops on my third Gen quad cab short box. In my class we ha EA to have a inch of rear travel and can't hang weight, would it be worth trying or not? What's the best way to make a set? I don't mean to hi Jack this post just figured the guys who already commented would know best, thanks for any advice
 
We put a go pro under the truck on the front stops to see what the front end was doing. It definitely shined some light on a couple issues we've been fighting.
 
Briggs0130 said:
We put a go pro under the truck on the front stops to see what the front end was doing. It definitely shined some light on a couple issues we've been fighting.
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I remember seeing a picture years ago of Rob Wright’s truck, he bolted a piece of angle iron to frame and a rod attached to the front axle that went threw a small hole in angle iron. Put an o-ring over the rod at the base of angle iron. Then you could see nose lift by how far it moved the o-ring. Just a different option than strapping a go pro under it.
 
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