Rear wheel hop when spining tires

[Guyzer]

Ive had my 2018 Raptor(50k miles, not abused) for a couple of months and notice the rear wheels hop pretty badly when they spin on loose or soft gravel. Im talking about little burnouts and tire spins in regular drive mode, no big off roading. I thought Raptors are supposed to have awesome handling with beefy shocks, but so far Im dissapointed with how it puts power to the dirt. Anybody know why this is happening?

 

[Keith88]

Shocks could need rebuild. Axle could of shifted.

 

[nikhsub1]

Ive had my 2018 Raptor(50k miles, not abused) for a couple of months and notice the rear wheels hop pretty badly when they spin on loose or soft gravel. Im talking about little burnouts and tire spins in regular drive mode, no big off roading. I thought Raptors are supposed to have awesome handling with beefy shocks, but so far Im dissapointed with how it puts power to the dirt. Anybody know why this is happening?

The OEM leaf springs are known for this unfortunately - they are the absolute worst part of the suspension in the Gen 2. Deavers +2 rear springs makes a world of difference.

 

[smurfslayer]

the rear wheels hop pretty badly when they spin on loose or soft gravel

Deavers +2 rear springs makes a world of difference.

I have yet to hear an explanation of how swapping leafs addresses axle hop or wrap, or both within the confines of Raptor suspension. Sure, slap on a bunch more leafs and you can stiffen it right on up. You’ll have a tooth jarring ride to accomplish this though.

If you ever watched the chase scene in Bullitt, Steve McQueen’s Mustang illustrates for you exactly what’s gong on, because it’s basically the same design.

Suspension Basics

by **** Miller It's a challenge to make traditional front engine/rear drive American cars hook and launch.

www.cartechbooks.com

this shows how the whole axle assembly shifts, but not the oscillation - struggling to find a good external video of it.


1) you apply power, maybe not even a lot, but, 3.5TT puts out big torque from down low.
2) passenger tire is planted and driver’s side tire lifted at the same time. The passenger side digs in and twists the axle, pushing the driver’s side wheel toward the front of the truck.
3) the lifted driver’s side wheel comes back down and rearward, regaining some traction but if torque is still applied, it’s only temporary and the cycle repeats.

Even this is a crude, simplistic write up, there’s more going on, but basically, Your Rap isn’t just hitting axle hop - up and down. It’s also hitting axle wrap - front to back.

All the spring in the world that you can practically use on a half ton truck are not going to answer this problem. It may make the reactions less perceptible to you in the cab, but it’s still happening.

There are 2 main answers here, both involve positively locating the axle, so that it can only travel up / down

1) traction bars. They hard mount to the frame and axle, allowing normal suspension travel but keeping the wheels pointed in the same direction while under acceleration.
2) torque arm. Similar idea; lower profile. About 95% as effective as stout traction bars.


Once you start stiffening springs, suspension compliance becomes an issue, creating a whole new set of issues. Our suspension needs to be soft to take impacts and still be compliant.

 

[GordoJay]

I have yet to hear an explanation of how swapping leafs addresses axle hop or wrap, or both within the confines of Raptor suspension.

There's a 2" block between the spring and the axle. Because of the extra leverage, the axle transmits more twisting force(torque) to the spring. Because the OEM spring has so few leaves, it's thin and it's ability to resist the torque is less than a spring pack with the same spring rate but more leaves. Ford cheaped out big time.

 

[2slo4u]

deaver's and a shock rebuild will great reduce axle wrap

 

[Guyzer]

Thank you for the information and suggestions. You would think a vehicle at this price point would be good to go off the lot. My last three F150's had no problems laying smooth power down to the dirt. What a dissapointment. How can they call this a Baja truck if it can't lay down some basic power in the dirt. From what I am learning, it looks like traction bars are the best solution for my wants, but that is going to set me back about $2,000-$3,000 installed, I am guessing. Does the Gen3 Raptor D link rear suspension resolve this wheel hop issue?

 

[2slo4u]

not sure what the pervious owner did with the truck but your rear leaf springs could be worn out.

 

[nikhsub1]

There's a 2" block between the spring and the axle. Because of the extra leverage, the axle transmits more twisting force(torque) to the spring. Because the OEM spring has so few leaves, it's thin and it's ability to resist the torque is less than a spring pack with the same spring rate but more leaves. Ford cheaped out big time.

This. This is the reason 100% If you've ever seen a deaver spring, you'd know they are ******* massive.

 

[Muchmore]

I keep a bunch of 2 liters of pop and Mentos in my truck just for when this happens, shit gets real QUICK!