improving turning radius with winch for rear axle?

[joshua180422]

So first off yes I did use the search option. I was thinking if I added a winch to the rear axle to lift up the rear axle it would help turning radius a lot and prevent less friction. I know that one issue you would run into is offroading when you flex but you could disconnect it and for on road purposes you shouldn't need to let too much slack out for flex. So has anyone tried this? Is it worth it? What size winch would you recommend?

 

[OilfieldRoughneck]

Never considered it, so a redneck tag axle setup?

 

[dawico]

I would imagine you would want to remove the driveshaft to that axle too then. If not the tires would be constantly slamming as you accelerated and stopped.

Winches are not designed to hold a load, only pull a load. As you hit bumps the axle would bounce and jerk on the winch cable. I think it would be better to jack the axle up and chain/ binder it.

Hopefully you are not doing this on a truck with ABS. That lifted axle would lock up with any brake pressure and give the system fits.

Just a few thoughts that I had while thinking about this same setup. Got the idea reading about guys disconnecting an axle but I just don't see how it would be worth the hassle.

 

[swbradley1]

It is possible to raise the axle and chain it up in an emergency to limp home but even with disconnecting the drive shaft I don't recommend driving it around like that and certainly not with a winch or 4 holding it up.

IMHO

 

[Swamp Donkey]

Not to be the pessimist, because I like ingenuity whether redneck or not, but here's my thoughts since I deal with the load-out of civilian truckers everyday.

In the 13 years I've been involved in the trucking industry I've never seen a truck able to legally travel with the drive axle lifted, or even able to lift one for that matter. I see over 500 trucks everyday of all shapes, sizes and ages. I see brand new Peterbilts, Kenworths and Macks getting their very first loads, and I've seen old heaps of junk that'd be burned to the ground by a DOT officer at first sight and I've seen everything in between. The lengths involving design and modification some of the OEMs and Owners go to, to haul that extra tonnage or save that extra gallon of fuel, can be a sight to see. It's impressive really.

But...I've never seen a drive axle lifted for traveling or just turning. This tells me it either isn't legal or just not worth it. We've got 2 trucks that come in here with 5 axles (3 tags and the tandems) on the trailer and they'll have all but the rear most axle raised when they come in empty. But those are non-driven axles.

If you were to swap in an interlocking axle that could be engaged and disengaged from the cab you might be closer but I think most of your main hurdles have been mentoned above. Even then, at what point do you say that it'd just be more feasible to...can't believe I'm about to say this...bob it? You haven't said which truck you have but what I have posted can be assumed for most trucks with tandems, military or civilian.

I'm not saying it can't be done, or hasn't been done, but there are people with a lot more time and money at stake than most of us, that haven't found it feasible.

Just some thoughts of mine and make sure to read the first sentence again.

 

[VPed]

I had considered an airbag setup. If you place a pair of bags between the frame and front-rear axle to push down, it would unload the rear-rear. My thought was you do not have to push so hard as to actually lift the rear-rear. You just have to slightly increase the amount of weight carried by the front-rear over the rear-rear. That should cause the truck to preferentially skid the rear-rear tires in turns. By not lifting the tires, there should be no issues leaving the drive system intact. That's my theory anyway.

 

[wreckerman893]

The rear suspension is a "walking beam" type that pivots on the center to allow the axles to adjust to the terrain. Defeating this operation will cause you nothing but grief.
If you want to improve the turning radius I think there is some adjustment on the front axle.
I have two M927's in the yard. The M927A1 with the 250 Cummins in it will turn tighter than the M927A2 with the 8.3 Cummins. Go figure?

 

[joshua180422]

I am sorry there is some confusion about what I am talking about. I am not talking about driving with the axle up. I am talking about making a turn into a driveway or parking. Not driving down the road or hold it for any length of time.

 

[dawico]

I am sorry there is some confusion about what I am talking about. I am not talking about driving with the axle up. I am talking about making a turn into a driveway or parking. Not driving down the road or hold it for any length of time.

Ah. I don't think you will gain much in turning radius. But it could be done.

 

[dilligaf13]

Chaining up the rear axle does reduce the turning radius slightly, but not much. I've seen it done, on a farm truck, with the rear tires and driveshaft removed. Kinda' like a redneck bobbed 5 ton. With that being said, I wouldn't take it on a road anywhere.

 

[lindsey97]

I have read your post and understand that you only want to do so at low speed while turning sharp. It might work but I doubt it. It is a cool idea, but I see one major problem. When you lift the rear, you will inadvertently change the driveline angles of the front driveshaft from tcase to input shaft of the front drive axle. This will cause problems, and will only get worse as speed is increased. Also as wreckerman stated, this is a walking beam suspension. When you hit a bump with the front drive axle, it will stress whatever you use to tie up and suspend the rear axle. Would probably change ride characteristics also.