LB7 BOUNCE

[White Lighting]

Any input on getting rid of this bounce why pulling? I have a DHD centerlink support, tierod sleeves, traction bars, 1 leaf added to the rear springs. Running 55lbs rear 30lbs front air pressure. About 1/4 track it start hopping bad! The truck has a protech composite box. I rolled the scales last night at 6450lbs. Maybe to light? Can't hang weight in this class.
TIA

 

[White Lighting]

Also torsion key bolts are all the way out when pulling.

 

[Chevy1925]

where is it bouncing? front or back end?

 

[Bdsankey]

Where is hitch height set? Is the rear blocked solid? Where is the hook point vertically in relation to the lower frame ears?


Got a video?

 

[White Lighting]

Hitch was set at 26 inches. Which is max height for this class. We can't black the rear solid. Has to have travel, I do have a lead added to the rear springs. Hook point is in the stock postion. I will get the video uploaded for you. Thanks for the help

 

[Chevy1925]

Hitch was set at 26 inches. Which is max height for this class. We can't black the rear solid. Has to have travel, I do have a lead added to the rear springs. Hook point is in the stock postion. I will get the video uploaded for you. Thanks for the help

how much travel is required? stil need to know where the bounce is starting at

 

[White Lighting]

Source: https://youtu.be/XB6Det4m0IE

 

[White Lighting]

The rules state factory travel

 

[Chevy1925]

you need more shock. you have no dampening going on back there and thats inducing the bounce. its starting at the back end and working its way forward.

 

[White Lighting]

I have rancho 9000rs adjustable on it. Set at the max. Any recommendations?

 

[Chevy1925]

not enough rebound control in them from what im seeing, pretty typical issue ive seen with them on shocks made for rear leafs

a double adjustable shock like qa1 or vikings would work well. you can tune the rebound and compression accordingly. start with 2-3 clicks stiffer from middle setting on both and see how it reacts. video each run and watch closely.

 

[ikeG]

Clamp the leaf springs together, in front and behind the axle.

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[Bdsankey]

I agree with James, looks like there is nothing going on in the rear to control it.

 

[SmokeShow]

You don't have front limit straps do you?

 

[White Lighting]

Clamp the leaf springs together, in front and behind the axle.

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That was the cure! Thanks!!

 

[ikeG]

That was the cure! Thanks!!

Awesome. If you didn't have the extra spring in the rear, this problem probably would not have surfaced. The leaf springs have just enough spring rate to convince them that they have enough power to lift the sled weight off your stops but it only works for a second. Lol
If the truck has rear suspension stops and you are setup well, in a typical '2" travel required' class, it technically does not need shocks at all. Except to meet the rules.

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[White Lighting]

I roll the scale at 7300lbs in a 8200lb class should I add some more weight to get closer to that 8200lbs?

 

[ikeG]

I roll the scale at 7300lbs in a 8200lb class should I add some more weight to get closer to that 8200lbs?

Yes. Fair warning, more weight equals more traction. More traction equals finding the next weakest link

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[Chevy1925]

Awesome. If you didn't have the extra spring in the rear, this problem probably would not have surfaced. The leaf springs have just enough spring rate to convince them that they have enough power to lift the sled weight off your stops but it only works for a second. Lol
If the truck has rear suspension stops and you are setup well, in a typical '2" travel required' class, it technically does not need shocks at all. Except to meet the rules.

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interesting to know, Isaac. appreciate the info!

 

[Leadfoot]

Max out the rear tire pressure. While slightly lower pressure will give you a better footprint (and theoretically better traction), any give in the rear sidewall will induce bounce, and bounce negates any added traction gained (or worse). The sled pulling down on the rear will give you plenty of traction (no need to lower rear tire pressure), plus as the rear sidewall squats you lose hitch height.

Lowering the front helps as forces want to lift it and a wider contact patch helps (tire isn't being squashed).

Traction bars in the rear would be ideal (if allowed), but springs clamps will help a lot if not.