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CSWolf · 10-21-2018, 07:18 PM

Witnessed a Mountainaire 400HP DP getting towed today in Anaheim Hills. The two company was towing it by the rear which I thought was not the best manner in which to do so? Broke down on the Imperial off ramp from the 91, yikes. Three police units involved in directing traffic. Double yikes.

Ray,IN · 10-23-2018, 08:47 PM

Lifting the rears sidesteps the issues of caging the rear parking brake canisters, and eliminates disconnecting the driveshaft. Sounds reasonable given the location, to save time on the scene. That is common practice when towing disabled road tractors.

Rotten-Red · 10-23-2018, 09:08 PM

Quote:

Originally Posted by Ray,IN

Lifting the rears sidesteps the issues of caging the rear parking brake canisters, and eliminates disconnecting the driveshaft. Sounds reasonable given the location, to save time on the scene. That is common practice when towing disabled road tractors.

It's true road tractors are towed that way most of the time. However there's a big difference between towing a rear engine diesel pusher and a road tractor. A road tractor is relatively lite on the rear. A diesel pusher is much heavier on the rear. It's possible to overload the steer axle towing from the back. Under normal driving conditions all the weight of the rear engine drivetrain unloads weight from the steer axle because the drive axle is the pivot point for which way the weight goes. When you lift the rear with the tow truck you push a lot of that weight up on the steer axle.

Mr_D · 10-23-2018, 09:14 PM

Not good and NEVER recommended.

twinboat · 10-24-2018, 04:38 AM

Could be that the rear wheel bearing burnt out and there wasn't a low boy trailer avalable. Any port in a storm.

Maybe my physics are bad, but if I pick up one end of a telephone pole, the other end gets heavier ?

Ray,IN · 10-24-2018, 07:38 AM

I didn't say it is good practice, I said it may have been for expediency to clear away the obstruction, anyone who has ever driven in CA knows about road congestion and traffic volume. Clearing away an obstruction is paramount to keeping traffic flowing, especially on a CA off-ramp.

Rotten-Red · 10-24-2018, 10:12 AM

Quote:

Originally Posted by twinboat

Could be that the rear wheel bearing burnt out and there wasn't a low boy trailer avalable. Any port in a storm.

Maybe my physics are bad, but if I pick up one end of a telephone pole, the other end gets heavier ?

No it doesn't. You're 100% correct.

In my post I stated: "It's possible to overload the steer axle towing from the back. Under normal driving conditions all the weight of the rear engine drivetrain unloads weight from the steer axle because the drive axle is the pivot point for which way the weight goes. When you lift the rear with the tow truck you push a lot of that weight up on the steer axle."

Think of the drive axle as a "teeter totter" because that's what it is as it pertains to weight distribution. Any weight added behind the drive axle will take a percentage of weight off the front axle. The greater the distance from the center of the drive axle to where this weight is added the greater the percentage of weight taken off the front axle and placed on the drive axle.

Now when the tow truck lifts the rear of the MH (usually about 12' behind the center of the drive axle) the drive axle teeter totter pivot point is gone. Now the weight the drive axle usually carryies is being shared by the tow truck and a percentage shared by the steer axle.

Dav L · 10-25-2018, 07:13 AM

Quote:

Originally Posted by twinboat

Could be that the rear wheel bearing burnt out and there wasn't a low boy trailer avalable. Any port in a storm.

Maybe my physics are bad, but if I pick up one end of a telephone pole, the other end gets heavier ?

Yes front gets heavier. I think though in practice that it depends on how high the rear gets lifted and the speed the vehicle is being towed and the quality of the roadway to determine if the front is truly "overloaded".
Just because the front says "14K lbs" doesn't mean it breaks at 15K. It means that for "normal" use, 14K being driven 70mph and hits dips in the road where all 14K lbs and its inertia gets pushed hard onto the front axle that it won't bend. The assumption that, if towed, it will be driven gingerly by the tow truck operator (hopeful thinking?). Also if the suspension is aired up and can take some of those dips in the road with compliance to spread the weight transfer (from the dip) across time.

hohenwald48 · 10-25-2018, 07:28 AM

Quote:

Originally Posted by Dav L

The assumption that, if towed, it will be driven gingerly by the tow truck operator (hopeful thinking?).

I don't think that tow truck operator has been born yet.

twinboat · 10-25-2018, 07:32 AM

Quote:

Originally Posted by Rotten-Red

No it doesn't. You're 100% correct.

In my post I stated: "It's possible to overload the steer axle towing from the back. Under normal driving conditions all the weight of the rear engine drivetrain unloads weight from the steer axle because the drive axle is the pivot point for which way the weight goes. When you lift the rear with the tow truck you push a lot of that weight up on the steer axle."

Think of the drive axle as a "teeter totter" because that's what it is as it pertains to weight distribution. Any weight added behind the drive axle will take a percentage of weight off the front axle. The greater the distance from the center of the drive axle to where this weight is added the greater the percentage of weight taken off the front axle and placed on the drive axle.

Now when the tow truck lifts the rear of the MH (usually about 12' behind the center of the drive axle) the drive axle teeter totter pivot point is gone. Now the weight the drive axle usually carryies is being shared by the tow truck and a percentage shared by the steer axle.

That is if its lifted by the chassis end. If lifted by the rear axle, ( long reach stinger ) the transfer would be marginal.

Rotten-Red · 10-25-2018, 10:09 AM

Quote:

Originally Posted by twinboat

That is if its lifted by the chassis end. If lifted by the rear axle, ( long reach stinger ) the transfer would be marginal.

Again, that would be correct. But when have you ever seen a tow truck with a 15' long stinger? I never have and I doubt that you have either. It would have to be at least that long to reach the drive axle and have room to turn corners when towing. Besides that, if there was a stinger that long when you load a 18,000 - 20,000 pound drive axle on it at that distance from the back of the tow truck it would take so much weight off the steer axle of the tow truck the driver would be lucky if he could keep it on the road.

With all due respect Twinboat, I read this forum frequently and have read many of your posts which are always filled with logical good information. But for some reason on this one you seem to be trying to pick fly_ _ _ _ out of pepper. Sorry!

Deucenut · 10-25-2018, 01:32 PM

I just went through this in August and had to have my Dutchstar towed. The first tow truck on scene couldn't pick it up by the front because my wheels were turned so he was going to pick it up from the rear. I immediately started trying to call Spartan etc to find out the correct way. He abandoned picking it up from the rear citing the fact my brakes were on and there was no air in the system(he didn't have a long enough air hose to reach the front). A lot of what he said didn't make much sense but he was a nice guy though.....

The second tow truck on scene, after telling him what the first driver had said, looked at me like I was crazy. He told me to NEVER EVER EVER allow anyone to pick the coach up from the rear for a few reasons:
1) the rear part of the frame is not part of the frame that runs the entire length of the coach. It is merely the engine cradle. The frame stops at the drive axle.(I'm still not sure if this is true or not, but it's not worth the risk)
2)If the coach is picked up from the rear, the drive axle hangs basically the coach sags in the middle which WILL cause major damage.
The second tow driver told me it most likely would have cause both my bedroom slides to go out of alignment and would most likely have caused major cracks in the sidewall gelcoat, among other things.

The second tow picked it from the front and removed the driveshaft. He was extremely professional and did a great job.

Dav L · 10-25-2018, 10:33 PM

At least on the Newmar, the chassis/ frame does go all the way to the back. My Bounder, (as example), has a frame extension welded to the chassis frame (that might be what the tow operator was speaking of).

If they pick up the rear from the tag, then yes, the drive axle will hang from the shocks. The chassis however won't "sag" much more than it normally does.

With all that said, I would still tow it from the front if that is accessible.

Slight detour for the thread: Remove the driveshaft or pull an axle stub and temporarily close off the open axle end (to keep the oil from departing)?
When mine was towed the driveshaft was pulled. It would have been really neat if the tow operator remembered to tape the ujoints bearing caps so they wouldn't fall off during the ride...

CSWolf · 10-26-2018, 11:29 PM

Deuce, same exact thing happened to me this summer. Sounds we had the same two tow drivers. I was going to get involved with this Mtnaire tow issue but the cops were there and they wanted the intersection cleared. Besides, some stranger walking up and trying to stop the tow would not have been looked upon favorably. Hope the guys MH is ok.