Rear wheel hop

First, the basics - '06 Ram QC, SB, 4X4, CTD, Anti-spin diff. On a recent camping trip, I thought I could save a little effort and back onto the beach to load my boat back on. Had the truck in four wheel low and backing down went smoothly as there was a bit of an incline down to the water's edge. After loading the boat the drive back up was a bit more interesting - there was quite a bit of rear wheel hop, almost violent, to the point I had to stop and try again 2 or 3 times. Has anyone found an effective solution to this for their Dodge? Thanks, Kevin

Reply to
kvand
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Let some air out of the tires.

Reply to
.boB

Yup, that and easy on the go pedal.

Roy

Reply to
Roy

THis can work but what cause wheel hop is driveline and wrapup from torque (rear springs and chassis) When pulling hard like this the rear spring wind up against wheel torque ( for ever action there is a equal oposite reaction) and then there is also a traction shift too and as drive tract winds up under load it tends to unload RR tire and load LR a equal amount. When traction is lost the engery stored in driveline and spring is released suddenly and causes the hop whish can get ugly sometimes. Cures? well as one suggested lower air pressure helps a bit of soft surfaces because it changes traction. A better long term fix is a stiffer rear suspension (add a leaf or two to rear axle) and better shock dampening. The light weight springs that they put is a

1500 for ride can realy wrap up under torque and this together with bigger stock tires or ofter market ones with relatively tall stock gears sets the stage for this to happen. (this is not just a Dodge problem either) You cannot have good drive axle torque control and a soft ride with just a few leaf springs. You need a coil over multilink suspension for that which you are seeing more of in some SUV's because it allows for a softer ride and excellant axle wrap/torque control too. With leaf springs you need to scarifice ride some and a add a few more leafs to better control the axle wrap up in conditions such as in this thread.

----------------- TheSnoMan.com

Reply to
SnoMan

He doesn't have a 1500

Reply to
Tom Lawrence

Hey Ass hole! You are doing it again, posting BS. Read the OP again.

Reply to
Roy

No matter, still can happen even more so due to high drive shaft torque but then there those that think that 1500 ft lbs of driveshaft torque or so has no effect on chassis/axle wrap up that can agrevate wheel hop. They believe that this all has not effect at all on traction. As you laod drive shaft it changes weight bias between rear wheels relative to torque input. When traction breaks loose the drive line unloads and weight bias changes then traction improves and weight start to shift again until traction is lost again and the cycle goes over and over and sometimes violently in some traction conditions. Fix include stiff springs, better shocks and deeper axle ratios that limit drive line torque relative to tractive effort.

THis first link shows the effect of tractive effort and axle ratio vs input torque

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This next link shows the amount of twist on springs when pulling a load up a hill. I could make one that show vs tractive effort but basically ther you can take the actaul tractive force you are placing on the ground (ie say 3000 ft lbs of draw bar pull) and multiply it by about 1.3 with stock tires and that is the amout of twisting force that the springs have to counter act or control and this is independant on thrust on push/pull axis too. So with 3000 lbs of pull there is and 4000 ftlbs of axle twist in springs in addtion to torque bias weight shift. Links give you a idea of effects

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----------------- TheSnoMan.com

Reply to
SnoMan

Your entire pontification was predicated on the fact that the OP was driving a 1/2 ton truck with "light weight springs for a soft ride", and now that it's pointed out that you made an incorrect assumption, it doesn't matter??

Facts just aren't welcome in your world, are they?

How's that V10 spark retard dissertation coming along?

Reply to
Tom Lawrence

SnoMan wrote:

Well, sort of. Ask any drag racer this question, and you'll get a slightly different answer.

It's a question of traction. During a hard launch (or "high" torque application), there's some axle wrap. Always has, always will be. Just a function of a leaf spring suspension. The tires grab the pavement and try to turn one way. The axle tries to turn the other way. The springs and shocks try to prevent that unwanted axle housing rotation. That works good until the tire reaches it's traction limit. When the tire breaks free, the axle housing snaps back due to it's pressure on the spring pack. When it grabs traction again, the cycle is repeated. You can try and make the springs stiffer. But a CTD already has pretty stiff springs. You could add stiffer shocks. But because of the way they are mounted, that really won't help much. You could add horizontal shocks, like Ford did in the mustang. That actually works pretty well w/o destroying the ride and handling. You could add an under rider style traction bar. I haven't seen anything off the shelf for this; you'd probably end up making your own. Not complicated, but could get expensive and time consuming. All of the above "solutions" will prevent the axle wrap and subsequent wheel hop. It will also make the suspension stiffer, worsen the ride, and make everyday handling worse. What they will NOT do, is improve traction. And that's the root of the problem. Instead of wheel hop, you get wheel spin. Which is probably worse. You managed to get up the ramp with wheel hop. You'll slide backwards with wheel spin. That would be fun.

That's why I suggested removing some air. It will increase the contact patch, soften the sidewall, and increase traction. It's temporary, and it's free. Watch a drag car take off, the sidwalls are so soft they actually wrinkle.

Reply to
.boB

No Tom actually ist is the same beacuse a CTD uses a lower axle ratio than a HD gas truck so there is more axle wrap up and you would know this if you really had a clue of the physics and dynamics of what takes place in a drive train with you step on the throttle but since you do not your responces are easily predicted. You are a real trip.

----------------- TheSnoMan.com

Reply to
SnoMan

Your a real Ass hole, now answer the question!

Reply to
Roy

He did answer the question man, didn't you hear him? He said "I'm a dumb ass and have no idea what I am talking about and you really shouldn't listen to me."

Reply to
azwiley1

Again.... WRONG! Care to guess what the standard axle ratios are for a

2500/Hemi vs. a 2500CTD vs. a 3500CTD? Here's a hint - they're all the same.
Reply to
Tom Lawrence

Hey, I've been saying that about you for a while now. Glad to see you finally admit to it

Reply to
TBone

Yeah, whatever Tom

Reply to
azwiley1

Shhhh!!!!!!!!!!!!!!!

don't confuse him with facts. it will just mess the whole world up.

Reply to
Chris Thompson

Oh yeah, facts.... bad....

Sorry 'bout that :)

Reply to
Tom Lawrence

Being smarter than the average bear ;>) , I've read, with interest, the replies that have been sent and have come to the conclusion that the simplest solution probably would have solved the wheel hop situation I experienced. You see, the tires on the truck were still in "tow mode" after hauling my 30' Jayco to the park where we were camped. That is, the fronts were at 60psi and the rears were at 70psi. Thanks bOB for the reply earlier

- I should have realized this myself, but oh well. Still, it might have been kind of cool to throw a set of traction bars at the thing - don't see too many 3/4 ton trucks with those., hehe Kevin

06 Ram 2500, CTD, QC, 4X4 unmodified yet - 5 years of warranty at stake.
Reply to
kvand

Being smarter than the average bear ;>) , I've read, with interest, the replies that have been sent and have come to the conclusion that the simplest solution probably would have solved the wheel hop situation I experienced. You see, the tires on the truck were still in "tow mode" after hauling my 30' Jayco to the park where we were camped. That is, the fronts were at 60psi and the rears were at 70psi. Thanks bOB for the reply earlier

- I should have realized this myself, but oh well. Still, it might have been kind of cool to throw a set of traction bars at the thing - don't see too many 3/4 ton trucks with those., hehe Kevin

06 Ram 2500, CTD, QC, 4X4 unmodified yet - 5 years of warranty at stake.
Reply to
kvand

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