Rear wheels hop when in snow

[stanzuray]

Had a M1031 for years now. Converted to a pickup but the rear spring pack is incredibly thick (info says it's almost a 2 ton pack because it's made to support the maintenance cab that it came with). So weak rear springs should not be an issue???
Anyway any time I get in snow that causes any spinning of the rear wheels (in 4 wheel drive or not, or low or high transfer case gears) it starts hoping bad. Lots of weight does help but only if the tires don't start spinning. If they do the truck hops. Had lots of different tires over the years regular radial ones and real wide 8 ply.
Did searching on this years back and on other forums to. Just thought I'd try it again. Ready to try some stabilizers or rear bars but thought I'd post this first. Speed is not an issue as it happens even just starting from a dead stop. Spring shackles and U bolts are solid. It's my daily driver and starts at 20 below with no plug in (like to plug in though) and only 16,000 on it now so drive train should not be sloppy (all u joints etc. seem tight).
Also if I'm on a real slick surface it will spin rear tires without hopping. But any grabbing by those rear tires with resistance like deep snow and it hops. Does this with chains on or not which I have on now as all the roads in this village have 4" of pack kept on them all winter.
Been a while since I posted - hello to everyone. Stan

 

[HN6]

Had a M1031 for years now. Converted to a pickup but the rear spring pack is incredibly thick (info says it's almost a 2 ton pack because it's made to support the maintenance cab that it came with). So weak rear springs should not be an issue???
Anyway any time I get in snow that causes any spinning of the rear wheels (in 4 wheel drive or not, or low or high transfer case gears) it starts hoping bad. Lots of weight does help but only if the tires don't start spinning. If they do the truck hops. Had lots of different tires over the years regular radial ones and real wide 8 ply.
Did searching on this years back and on other forums to. Just thought I'd try it again. Ready to try some stabilizers or rear bars but thought I'd post this first. Speed is not an issue as it happens even just starting from a dead stop. Spring shackles and U bolts are solid. It's my daily driver and starts at 20 below with no plug in (like to plug in though) and only 16,000 on it now so drive train should not be sloppy (all u joints etc. seem tight).
Also if I'm on a real slick surface it will spin rear tires without hopping. But any grabbing by those rear tires with resistance like deep snow and it hops. Does this with chains on or not which I have on now as all the roads in this village have 4" of pack kept on them all winter.
Been a while since I posted - hello to everyone. Stan

My dodge does the same thing. Your axle is twisting. Add some traction bars and it will get rid of the axle twist and hop.

 

[stanzuray]

My dodge does the same thing. Your axle is twisting. Add some traction bars and it will get rid of the axle twist and hop.

Reading your comment made me think of how traction bars would maybe work and I realized that the thick spring pack I have on there even though massively strong puts the axle over 5 inches below the level of where the springs are mounted to the frame. This is way more than most trucks. I have 9 leaf springs in the pack and one real heavy helper spring on top of that. Maybe that is allowing the "give" in the axle and a traction bar would help. I know there are different types so anyone one got any ideas be appreciated. Also any other thought also.

 

[JD4044M]

I have 11 springs and a real thick over load. My rear tires won't hop on my 79 Chevy 1 ton I can smoke the tires in snow, gravel, dirt or street with no hop but I have good rear shocks.

 

[stanzuray]

I have 11 springs and a real thick over load. My rear tires won't hop on my 79 Chevy 1 ton I can smoke the tires in snow, gravel, dirt or street with no hop but I have good rear shocks.

Thanks -that is another idea. I have regular 3 year old ones maybe get some real expensive ones.

 

[JD4044M]

Loose bushing on the leaf spring ends, rear end out of alignment one side forward or back more then the other side? Spring pack moved?

 

[Garagefull]

Be sure that the clamps on the outside ends of the spring packs are intact. They keep the spring packs from spreading open under load. I had a similar situation on a big block one ton. Also be sure that the leaves are a smooth curved arc,not wavy so to speak. When they are no longer a arc,the leaf springs Cannot smoothly travel over each other and can cause your issue.

 

[stanzuray]

My dodge does the same thing. Your axle is twisting. Add some traction bars and it will get rid of the axle twist and hop.

Be sure that the clamps on the outside ends of the spring packs are intact. They keep the spring packs from spreading open under load. I had a similar situation on a big block one ton. Also be sure that the leaves are a smooth curved arc,not wavy so to speak. When they are no longer a arc,the leaf springs Cannot smoothly travel over each other and can cause your issue.

Clamps and springs look solid and tight. I'm going to put a go pro camera on ot and make it hop.

 

[HN6]

Clamps and springs look solid and tight. I'm going to put a go pro camera on ot and make it hop.

I was watching axle wrap videos on youtube after you posted this. One of the guys mounted a camera and recorded it, but he was pushing way more h.p. than me.

My truck will only hop in deeper thick wet snow.

 

[Keith_J]

Loose suspension and worn shock absorbers. Stiff springs are one thing, axle mass another. This makes a spring-mass pair which will oscillate at a certain frequency. The ability of the shock absorbers to damp this oscillation is what keeps hop minimal. You may still have low frequency damping (at large suspension travel) but have lost the higher frequency effectiveness (smaller displacement).

 

[Tinstar]

Tire pressure might also affect hop

 

[stanzuray]

Appreciate all the replies. Some ideas here that I will be working on. When I do a video I'll update the post. Stan

 

[royalflush55]

Try not having the same tire psi in front and back. Try more and less in each and see if it helps!

 

[linemech31]

I have never been able to drive a full size pickup that didn't have a bouncy rear end in snow at low speed.

 

[linemech31]

I have never been able to drive a full size pickup that didn't have a bouncy rear end in snow at low speed.

I should have elaborated further. The rear end hop in snow seems to be variable depending on stiffness of suspension amd tire lug height. An unloaded 3/4 ton in 2x4 with aggressive tires hops bad. Soften the springs and/or reduce tire lug profile it changes drastically. Much less hop. I am sure any worn bushings,bearings etc would compound the problem