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There are devices that do the same thing by hydraulically forcing a roller between the wheels. They're called Robson drives and are pretty common on trucks where I live.
i looked it up thinking it would be somewhat more sophisticated than the log but nope, it’s literally just pushing a cylinder between the wheels. fascinating stuff.
They also make more advanced systems with a hydraulically driven roller for forestry trailers. Same basic principle, but it takes power from the harvester/tractor/whatever and actively drives the wheels, turning a zero wheel drive trailer into a four wheel drive.
A diff lock locks two halves of an axle together. Without diff lock, if one wheel on an axle spins, all the power is sent to that wheel while the wheel with traction remains motionless. This method with the log is a trick to drive an unpowered wheel
Basically the same thing but between axles instead of between wheels on the same axle, yeah. It looks like only the rear rear axle is powered on this truck but if it was one where both were powered it might have an inter-axle differential lock to force all wheels to spin at the same rate.
Close. A diff lock locks 2 halves of an axle together to provide equal power to each side. Normally, the diff will allow each wheel to spin at different speeds whilst cornering.
What you're seeing is when you have 2 driven axles (or a driven axle and the other is called a lazy axle which isn't driven) and one wheel on one axle loses traction, making all the power from both axles go to the one with the least traction. A device called a cross lock will lock the power split to both axles equally (providing both axles are driven)
What the log is doing is acting as an idler wheel, transferring rotational force to the other wheel which does have traction.
Thx, I looked it up also. I'm surprised I've never seen this. Is there an obvious reason it's used in your part of the world? Where region do you live in?
I'm in Finland. I've mostly seen them on dump trucks at construction sites, I guess they're good for occasionally climbing steep inclines at construction sites in crappy weather (mud, snow, ice) where traditional 4WD systems wouldn't be worth the extra weight, complexity and cost.
this is less “increasing traction” and more “all wheel drive”
you can see before the log is put in, that the drive wheel is the rear. the log just connects the two wheels so that both are connected to engine power. the one in the front is doing all the pulling because it has some traction (so it is *technically* increasing traction, but not in the sense that the rear suddenly has more traction because of a log)
More wheels driving, more surface contact, more traction
Edit: though in reality I think the guy just locked his diff during the pause, that log aint doing shit
No, he didn't wait for it to stop, it simply happened less than a second before the log impacted the tire. It seems unlikely that the driver did that on purpose. This is needlessly risky.
The front tire has traction, the rear tire doesn't. Power from the differential is spinning the rear tire uselessly, without transferring enough to the useful tire (or any power at all? Not actually sure how big rig drive trains work.).
The log acts as an intermediary gear and "links" the two wheels, so they have to spin at the same rate. It's not a trick of *traction* per se, like the title indicates... just mechanical linkage. Still, it works better than I'd expect.
The driver engaged secondary axle. 120psi tires at most, and that truck weights around 80 thousand pounds. That log would of just sqeezed through the tires and dropped to the ground.
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There are devices that do the same thing by hydraulically forcing a roller between the wheels. They're called Robson drives and are pretty common on trucks where I live.
Fascinating. I’ve never heard that before. I looked it up. Thank you for teaching me something.
i looked it up thinking it would be somewhat more sophisticated than the log but nope, it’s literally just pushing a cylinder between the wheels. fascinating stuff.
They also make more advanced systems with a hydraulically driven roller for forestry trailers. Same basic principle, but it takes power from the harvester/tractor/whatever and actively drives the wheels, turning a zero wheel drive trailer into a four wheel drive.
This one wouldn't become a high mass projectile.
?
I’ve heard of something called Differential lock, is it similar to (or the same as) that?
A diff lock locks two halves of an axle together. Without diff lock, if one wheel on an axle spins, all the power is sent to that wheel while the wheel with traction remains motionless. This method with the log is a trick to drive an unpowered wheel
Available on the 1963 Pontiac Tempest.
Not the 64 skylark?
What is a grit?
Driven by two yutes?
They were so close then went completely off script
Are you suuuuure?
Marisa Tomei. Yum.
Basically the same thing but between axles instead of between wheels on the same axle, yeah. It looks like only the rear rear axle is powered on this truck but if it was one where both were powered it might have an inter-axle differential lock to force all wheels to spin at the same rate.
Close. A diff lock locks 2 halves of an axle together to provide equal power to each side. Normally, the diff will allow each wheel to spin at different speeds whilst cornering. What you're seeing is when you have 2 driven axles (or a driven axle and the other is called a lazy axle which isn't driven) and one wheel on one axle loses traction, making all the power from both axles go to the one with the least traction. A device called a cross lock will lock the power split to both axles equally (providing both axles are driven) What the log is doing is acting as an idler wheel, transferring rotational force to the other wheel which does have traction.
No
Thx, I looked it up also. I'm surprised I've never seen this. Is there an obvious reason it's used in your part of the world? Where region do you live in?
I'm in Finland. I've mostly seen them on dump trucks at construction sites, I guess they're good for occasionally climbing steep inclines at construction sites in crappy weather (mud, snow, ice) where traditional 4WD systems wouldn't be worth the extra weight, complexity and cost.
I always wondered just what those did. I always assumed they were for lateral stability.
I have those on my truck, as long I remember to hit the switch before I get stuck, then those are great help.
He does? I always thought he was more of a strolling and rolling kind of guy
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That's pretty log ical.
Gotta add this one to my ana log of puns
Thats awful. Go ahead and log out for me.
Don't get board!
I can't believe you wood make such pun
Instructions unclear, 2x4 lodged in cranium
Its big, its heavy, its wood. Its better than bad, its good
It rolls down stairs, alone or in pairs, and over your neighbor's dog.
Its great for a snack and fits on your back.
It’s log, log, log!
What have I got in my pocket?
Log, from BLAMMO! 💥
It’s logggggg loggggg
Everyone knows it’s log
Ren and Stimpy had entered the chat!
Happy happy JOY JOY!!!!
Eets the elusive croco-stimpy!
Yes sir, I like it.
this is less “increasing traction” and more “all wheel drive” you can see before the log is put in, that the drive wheel is the rear. the log just connects the two wheels so that both are connected to engine power. the one in the front is doing all the pulling because it has some traction (so it is *technically* increasing traction, but not in the sense that the rear suddenly has more traction because of a log)
More wheels driving, more surface contact, more traction Edit: though in reality I think the guy just locked his diff during the pause, that log aint doing shit
If looks like that's what he did, the log didn't need to squish into the tires before rotating the front ones
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"Give me a log, and I shall unstuck a stuck 16 wheeler" Plato
"Shitters full!" Cousin Eddie
"Brooks was here" Brooks Hatlen
"If you tie a string around your finger real tight, you can make it turn purple." Nelson Muntz
"I love lamp" Brick Tamland
Plus a place to stand
Ah there it is. Reddit never misses a chance to sound smart.
https://xkcd.com/857/
what diff lock does to a mf
diff log maybe?
Came here to comment logking diffs
Did the wheels need to be actively turning when he put the log in there with his *hands*?
While incredibly unsafe, it did actually help drive the log down between the axles so there was more traction between the axles and the log.
The wheels stopped when he put his hand forward to place the log. You need to be patient and give your brain some processing time.
No, he didn't wait for it to stop, it simply happened less than a second before the log impacted the tire. It seems unlikely that the driver did that on purpose. This is needlessly risky.
From BLAMMO!
Always have a perfectly sized log with you when you're driving a truck through gravel ! Noted.
Essentially you gain 1 more tire
We have self-locking differentials and 6x4 in our Trucks
This isn’t traction, it’s torque. Also, and importantly, I have no idea what I’m talking about.
You break your spaghetti in half before boiling, don’t you?
What other kind of logs are there?
Doodoo logs. Probably wouldn't work nearly as well though.
Peanut butter logs are pretty good.
Cheese.
Smart. More tension, more traction. Simple solutions to difficult situations.
like sex
Exactly! More tension, more sexism.
Clever.
Can someone explain this in a way to understand the physics behind whats Happening here?
The front tire has traction, the rear tire doesn't. Power from the differential is spinning the rear tire uselessly, without transferring enough to the useful tire (or any power at all? Not actually sure how big rig drive trains work.). The log acts as an intermediary gear and "links" the two wheels, so they have to spin at the same rate. It's not a trick of *traction* per se, like the title indicates... just mechanical linkage. Still, it works better than I'd expect.
Stone Age Difflock
Clever
I swear I read…”using a wooden Leg” and I about fucking died laughing. Hahaha
Make sure you put that log back in the truck
I think its pretty dam slick
Poor man's diff lock for lorries.
because your tire cant spin out and slide back
Misread the title as wooden leg and thought the man had a prosthetic leg and was gonna put in the tires. >!Then I thought it was his penis!<
The driver engaged secondary axle. 120psi tires at most, and that truck weights around 80 thousand pounds. That log would of just sqeezed through the tires and dropped to the ground.
it makes since, i wonder if this has anything to do with tanks or excavators as well
Love the random Batman
Wood always solves the problem
And traction control was born.
Isn't this just because of the split differential? Can't they lock it for exactly this situation?
Damn thats genius!
That big ass sandwich really saved the day
Am I wrong in saying this is basically doing the same as a diff lock?
Yes
Care to elaborate?
Diff lock, is locking the differential gears between wheels on the same axle. Not wheels on seperate axles
I understand how a diff lock works. To me this seems to be basically a diff lock between wheels on the same side of the vehicle
why did you ask question if you didn’t want answer.
I do want an answer. One which isn't just no and telling me what I already know
Oh I see, then in that case it is identical and it’s the same technology many World War 2 tank crews used to unstuckify their tracks from mud.
No shit. That’s how it works.
But why did the wheels have to be moving when he threw the log in?
They literally weren't moving when he threw it in..
You're right. I thought I saw them moving when I first watched it.