The "Trick" 90 degree turn?

[scottymcdonald]

I've been curious to actually see a 4x4 Sportsmobile do this 90 degree turn using front wheel drive with the rear brake engaged.

Its described here at 4:30 https://www.youtube.com/watch?v=2XkUvYn-T0M

Any one know of a video of someone pulling this off?

 

[Mwilliamshs]

This front-wheel-drive-only maneuver is known in the off-road world as a "front dig."

Several videos out there to be found by searching with this name.

Toyota reverse donuts

Big Mud Truck Demo

Jeep makes a nice 90* turn at the end of this one

 

[Skooter_Built]

Not difficult at all, only requires a transfer case like an Atlas II.

 

[1leglance]

I did it a few times in my SMB...but it feels strange and isn't something I would do all the time.

The method was simple,
be in 4wd lo range
Lock the emerg brake
shift the rear drive shaft into neutral
turn on front lockers,
crank the wheel but NOT to full lock
ease on the throttle and be careful....

I tried it a few times with without the ebrake on but didn't work as well

 

[AA1PR]

seen his personal rig at VT ORW a couple times, its an impressive rig

 

[Mwilliamshs]

I did it a few times in my SMB...but it feels strange and isn't something I would do all the time.

The method was simple,
be in 4wd lo range
Lock the emerg brake
shift the rear drive shaft into neutral
turn on front lockers,
crank the wheel but NOT to full lock
ease on the throttle and be careful....

I tried it a few times with without the ebrake on but didn't work as well

locking the front axle is contrary to tight turning and puts added stress on the front end components. unless it's totally necessary for traction (one tire off the ground for example) I'd strongly advise against turning sharply with a front locker engaged, whether in FWD only or 4wd, etc. Even in 2wd rear, a locked front end won't turn as well as one with an open differential. With an automatic front locker it's actually common to unlock a hub for sharp turns for benefits in both maneuverability and durability.

 

[1leglance]

My SMB was 11,000lbs and just would not pull itself around without BOTH front tires working...
I would always try without the front locker but I remember that many times I would need to lock to make it happen

Lucky for me I never did this method more than 10 times when I owned that rig and always very slowly and carefully

 

[ExploringNH]

locking the front axle is contrary to tight turning and puts added stress on the front end components. unless it's totally necessary for traction (one tire off the ground for example) I'd strongly advise against turning sharply with a front locker engaged, whether in FWD only or 4wd, etc. Even in 2wd rear, a locked front end won't turn as well as one with an open differential. With an automatic front locker it's actually common to unlock a hub for sharp turns for benefits in both maneuverability and durability.

In a front dig situation you want both tires to be spinning (slowly) so that the truck can rotate around. It isn't a normal turn. You need to break traction. Locker engaged will work much better.

 

[Mwilliamshs]

...You need to break traction. Locker engaged will work much better.

counter-intuitive to break traction by engaging the locker and certainly counter-intuitive to turn by ceasing differentiation between tires on opposite sides of the vehicle. I've been there and done it. Digs work best for me if I leave the front unlocked (mine's a spool so i unlock the hub on the inside tire) and leave the rear in neutral and the parking brake off, crank the wheel in the desired direction, initiate the turn with throttle and as soon as tires roll stomp the e-brake. This lets things get started without dragging the full weight of the rig then stops the rear dead and it just pivots. This is currently a 79 f250 standard cab, longbed but the np205 in it has been in a bronco before that and a k30 flatbed (ford axle) before that. deer camp rigs/firewood haulers.