Backhoes and loaded tires

[PA452]

When the tires are off the ground being held up by stabilizers you致e got maybe a ton of tire and fluid hanging on the axle. And it痴 just a static load. No bouncing, rolling, or side pressure. When the tire is in the ground you致e got 3 tons of machine sitting on them shared between both of them.

I'm not saying you're wrong, because I don't know. But it's not entirely an apples to apples comparison either. The weight applied to the axles while sitting on the wheels is applied one direction. The weight of loaded wheels hanging off the axles of a raised tractor is applied the opposite direction. Maybe they just didn't design it for that?

 

[4570Man]

They’re taper roller bearings. It makes no difference. Now I guess you could say the housing is thicker on the topside but all the ones I’ve seen are uniform. Even if they were built stronger on top they should be being the weight of the machine driving around hitting bumps plus the traction of the tire pushing the machine forward is way more than the weight of the tires.

 

[PA452]

Yeah, it wasn't the bearings I had in mind. Regardless, I'm just guessing. I'm sure there's some reason our manuals say don't load the tires with a backhoe.

 

[4570Man]

Yeah, it wasn't the bearings I had in mind. Regardless, I'm just guessing. I'm sure there's some reason our manuals say don't load the tires with a backhoe.

Maybe it’s nothing to do with the axel and they’re worried about the excess weight causing wear on the transmission or possibly damaging the front loader with more traction. On the flip side it’s stressing the weakest point of the drive train the front axel less.

 

[Diggin It]

This has been coming up periodically for almost 20 years! When I bought my 4560 backhoe back then, the dealer told me the issue with backhoes and loaded tires had nothing to do with tires, axles, hydraulics, or chassis strength... it was a physics issue with rotational moments of force in a rollover. The ROPS can generally prevent a 180 or 360 deg. rollover with a backhoe OR loaded tires + an implement in back but would not do as well with backhoe + loaded tires. So, according to those guys, it's a corporate CYA thing to advise against this practice. That sort of made sense to me at the time, but it probably hasn't held back many owners from loading their tires! I do know that backhoe was one heavy son of a gun and really planted the back end of the tractor to the ground.

Probably makes as much sense as anything, but it would be better if they simply explained the why in the notices.

 

[Notforhire]

This has been coming up periodically for almost 20 years! When I bought my 4560 backhoe back then, the dealer told me the issue with backhoes and loaded tires had nothing to do with tires, axles, hydraulics, or chassis strength... it was a physics issue with rotational moments of force in a rollover. The ROPS can generally prevent a 180 or 360 deg. rollover with a backhoe OR loaded tires + an implement in back but would not do as well with backhoe + loaded tires. So, according to those guys, it's a corporate CYA thing to advise against this practice. That sort of made sense to me at the time, but it probably hasn't held back many owners from loading their tires! I do know that backhoe was one heavy son of a gun and really planted the back end of the tractor to the ground.

I'm with Diggin it. The explanation given by Grandad4 is about the closest thing to logic that supports this warning, that I've heard.
My dealer also suggested that it probably was more of a CYA move by the legal dept. than a (don't do this or you'll break your tractor) precaution by the engineering/design dept.

I would also agree that the loaded tires would increase the strain on the outriggers, but it must pale in comparison to the force applied to them while digging/lifting rocks or breaking roots in a trench.

 

[Notforhire]

Just for the heck of it, I looked up what the replacement cost would be for the bent main frame on the first backhoe I got. $4,427.35
That's just the part, no shipping, no installation!
I can't imagine what the total repair bill would be.

 

[Smokeydog]

Have to agree with Grandad4. Excuse rather than logic. Engineering analysis clearly hasn’t resolved the ROPS/backhoe/ballast variations so legal CYA has. Granted it would be a challenge to calculate ROPS integrity to pole vault the whole TLB backwards, downhill over a extended boom over solid rock onto the top of the ROPS where ballast in the tires would increase the impact force.

For me it is more important to prevent sideways rollover by adding ballast. I’ll bet my safety on common sense over legalese every time.

 

[RickB]

You read enough operators manuals (and I’ve been a dealership employee for almost 23 years) and you will find a lot of conflicting info, bad information and things that make you go hmmmm.

 

[Grandad4]

Granted it would be a challenge to calculate ROPS integrity to pole vault the whole TLB backwards, downhill over a extended boom over solid rock onto the top of the ROPS where ballast in the tires would increase the impact force.

A front/back rollover was probably not the major concern. A lateral rollover is much more common, wouldn't you think? Possible causes of a sideways tip over/rollover: soft ground, tire failure, sideways on a slope, or some combination thereof. Also an accident while roading, or operator error, etc. Could happen while operating the BH or just traveling about.