Tractor "bouncing" ?

[jeff9366]

Low inflation pressure radial tractor tires ride much more smoothly than other tractor tires.

 

[k0ua]

That makes sense.

Since adding liquid ballast to tyres, or wheel weights to the rim, results in additional mass that does not "stick out" beyond an axle, does that effectively make the length of those "torque arms" zero (or, at least, minimal)? Would either of those approaches be a valid way to reduce the bouncing?

Or would additional mass (hypothetically) need to be added between the axles to be effective?

I am reasonably confident that remove the rear ballast and putting in liquid ballast in the tires will make some change. I am more confident that taking the FEL off will make a larger change. Again of no value for your application. I am also MOST confident that slowing down will effect the largest change. As far as 2WD and 4WD, I have notice the most effect of this "torque windup" caused by being in 4WD to have the largest effect when turning, causing tire scrubbing on hard surfaces. But I doubt you would notice this in soft dirt or sandy conditions.

 

[deezler]

I feel like dodge man hit a solid point on the first reply in this thread, that didn't get answered: What are your tire pressures?

Drop to 10 psi and report back. It's ok to see your front tires squish a bit. You need to use your tire sidewalls as suspension.

Edit: 32psi... thats nuts. I run 10-12 psi.

 

[crashz]

As mentioned before, this happens on large wheel loaders and backhoes as well. Most new models have a feature that dampens the main loader boom to help prevent this (Ride Control). Anyone who has taken them down the road at road speed knows how they will begin to teeter-totter. Anything can set it in motion (bumps, acceleration, braking, etc) and the oscillation becomes worse and worse. My fathers Cat 416 was so bad you would have to come to a complete stop regularly to control it.

Speed has everything to do with it. And if you are carrying a heavy bucket of sand with a heavy counterweight, you need to carry it low and slow. How fast are you going, IE which range, pedal pressure and throttle? If you need to move a considerable amount of sand fast, consider a dump trailer or truck.

Significant bouncing will probably go after your weakest links. I'm thinking the front axle, loader and loader mounts are taking a beating right now.

 

[Agvg]

Would consider comfort ride on the loader, reduced wear and more comfort.

 

[Hay Dude]

Would consider comfort ride on the loader, reduced wear and more comfort.

It does help, but its not a cure. I'll spear 2 4x5 round bales and drive down the road with them and the tractor ride quality is at least 50% better with KSR turned on. Takes the stiff pounding out.

 

[timbrr]

timbrr....I have neighbors that have big end-loaders and also road crews use them, and they will get bouncing on a SMOOTH road surface. I have a feeling that off-road tires are not as round and consistent thickness as on-road tires. If they all start acting in unison, then you get bouncing. Just like them

Can I check tyre roundness/consistency by simply jacking up a wheel, spinning it, and just looking for "wobble"? Or is there more to it than that?

The bouncing you describe does seem to happen more on smooth surfaces more.

Yep. I rarely bounce on 'slightly rough' surfaces. Sometimes I deliberately put one side of the tractor off the track (into the rough) just to dampen the effect -- that seems to work well, but does end up ruining the vegetation in the area even more.

 

[oosik]

My 2009 Kubota M6040 has a HD 820# grapple on the FEL, 1550# of RimGuard in the rear tires & a 1000+# Rhino rear blade on the 3-point. All tolled the tractor weighs - 10,000+ pounds. Unloaded or fully loaded - it will bounce traversing certain terrain.

This is a signal that I am going too fast. Slow down..........

I have max pressure in my front tires and 14# in the rear tires.

Bouncing is not only uncomfortable for the tractor operator - it puts undue strain on many tractor components.

 

[timbrr]

I suspect this is exactly what is happening to the sand, the front wheels turn just a little faster so they tend to mound up the loose sand a bit with each pass and eventually this starts the harmonic "loping " so you end up bouncing up and down in the seat. Each time the tires run over the humps they react more and more so you end up with a big up and down, front to back hop. Back dragging to remove the humps results in a smooth ride for a couple trips till the front wheels throw up the humps again.

This sounds plausible.

Try travelling in 2WD if it is safe to do so, ie, not hills to traverse where you might loose rear wheel traction.

I'll try that, just to see if it helps, but I don't think constantly switching between 2WD and 4WD is really a practical solution especially when transit times are in the order of 30 seconds. The time lost changing drive mode would almost certainly be greater than the time lost just going slower. The 5100 does not have a way to quickly/easily switch between 2WD and 4WD, unfortunately.

 

[timbrr]

Many cars have weights bolted to the drivetrain or bodies in strategic points to change the system natural frequency, mostly to improve nvh.

NVH?

Try playing with tire pressure to change the suspension stiffness.

Will do.