DIFFLOCK66 · Sep 19, 2013

I don't know? Interested to find out, though not by practical experimentation with mine. Will it try and kangaroo around?
Edit:- will it cause a spin?
Diff.

200tdi ayre · Sep 19, 2013

jamesmartin said:
youve never seen one with both rear wheels going in opposite directions,perhaps some study on how diffs work ,and which way opposite wheel goes if you turn the other

Of course I know how a diff works, I only work on vehicles every day :doh:

My argument still stands, the handbrake as an Emergency brake is still better than not bothering even trying

jamesmartin · Sep 19, 2013

200tdi ayre said:
Of course I know how a diff works, I only work on vehicles every day :doh:

My argument still stands, the handbrake as an Emergency brake is still better than not bothering even trying

except you wernt sure what wheels did,so still stuff to learn,oh yes better than nothing ,but my point was not to try and use like a std handbrake that works on the rear wheels

200tdi ayre · Sep 19, 2013

jamesmartin said:
except you wernt sure what wheels did,so still stuff to learn,oh yes better than nothing ,but my point was not to try and use like a std handbrake that works on the rear wheels

Because when I bump start (very rarely) I usually do it in the right gear, I know that the wheels would try to turn in opposite directions but have you ever tries to break traction with a tractor

jamesmartin · Sep 19, 2013

200tdi ayre said:
Because when I bump start (very rarely) I usually do it in the right gear, I know that the wheels would try to turn in opposite directions but have you ever tries to break traction with a tractor

i did grow up on a farm and i am also a qualified agricultural engineer, so you can understand why yanking on transmission brake isnt necessarily a good idea

200tdi ayre · Sep 19, 2013

jamesmartin said:
i did grow up on a farm and i am also a qualified agricultural engineer, so you can understand why yanking on transmission brake isnt necessarily a good idea

I never said it was good, but I wouldn't have a second thought about doing
It if I had to

jamesmartin · Sep 19, 2013

200tdi ayre said:
I never said it was good, but I wouldn't have a second thought about doing
It if I had to

thats the whole point ,you should have a second thought if using a transmission brake at any form of speed

200tdi ayre · Sep 19, 2013

jamesmartin said:
thats the whole point ,you should have a second thought if using a transmission brake at any form of speed

Anything I could do to slow down a crash is fair game, normal brakes, dropping gears and if all else fails handbrake, it's
Just common sense mechanical sympathy goes out the window in an emergency

DIFFLOCK66 · Sep 19, 2013

So.... what does happen yanking on the transmission brake? (Note: I did no it was a no-no before getting into all this, but I'm curious.

Ta.

200tdi ayre · Sep 19, 2013

DIFFLOCK66 said:
So.... what does happen yanking on the transmission brake? (Note: I did no it was a no-no before getting into all this, but I'm curious.

Ta.

The rear prop will stop turning (or almost) and so the wheels will want to turn in opposite directions as you will still be traveling forward so the diff will try and spin as the wheel with the most grip tries to turn the other wheel the opposite way, this could lead to a lovely action from the back end, a broken diff/half shaft or a spin

DIFFLOCK66 · Sep 19, 2013

200tdi ayre said:
....or a spin

Ah, thanks! So I was guessing along the logical line of thought.

200tdi ayre · Sep 19, 2013

DIFFLOCK66 said:
Ah, thanks! So I was guessing along the logical line of thought.

We've got a customer who's front wheel bearing collapsed and seized, she spun in the middle of a main road, and this would be a similar effect

quattro6999 · Sep 19, 2013

200tdi ayre said:
The rear prop will stop turning (or almost) and so the wheels will want to turn in opposite directions as you will still be traveling forward so the diff will try and spin as the wheel with the most grip tries to turn the other wheel the opposite way, this could lead to a lovely action from the back end, a broken diff/half shaft or a spin

You would think so, but bear in mind that both wheels will be on the ground, so they can't contra rotate due to the forward motion, plus the fact that the prop can't turn (as it's locked by the handbrake) so the wheels can't turn as the prop is stopping the diff from turning.
Yanking the transmission brake on at speed is liable to cause some damage somewhere.
Have done handbrake turns on snow/ice, quite fun

200tdi ayre · Sep 19, 2013

quattro6999 said:
You would think so, but bear in mind that both wheels will be on the ground, so they can't contra rotate due to the forward motion, plus the fact that the prop can't turn (as it's locked by the handbrake) so the wheels can't turn as the prop is stopping the diff from turning.
Yanking the transmission brake on at speed is liable to cause some damage somewhere.
Have done handbrake turns on snow/ice, quite fun

That's the theory anyway

Your prop not turning is the reason the wheels counter rotate as because the prop can't turn tye wheel with more grip will send power through the diff to the other wheel turning it in the opposite direction, but your right it would have to break traction with the surface first

Hand brake turns in cars are different as they brake the hubs not the transmission so this effect doesn't happen

DIFFLOCK66 · Sep 19, 2013

200tdi ayre said:
Hand brake turns in cars are different as they brake the hubs not the transmission so this effect doesn't happen

I know that only too well

who needs 3 point turns? With the exception of my Disco, all my cars have done handbrake turns, usually more often in winter...

SteNova · Sep 19, 2013

So if I have to use it in an emergency I need to engage my rear locker first?

D90mitch · Sep 19, 2013

SteNova said:
So if I have to use it in an emergency I need to engage my rear locker first?

Don't think yer ring and pinion would be thrilled by that but you might save yet half shafts

jamesmartin · Sep 19, 2013

SteNova said:
So if I have to use it in an emergency I need to engage my rear locker first?

would be safer

easye1 · Sep 19, 2013

jamesmartin said:
except you wernt sure what wheels did,so still stuff to learn,oh yes better than nothing ,but my point was not to try and use like a std handbrake that works on the rear wheels

reading through this thread with its fors and againsts,
must add I "warm" up my handbrake when its cold outside, but only in the lower gears = slow speeds.
another point missed with your comment James,
back in the day (series period) commer vans had the hand brake on its front wheels I believe = interesting Idea In cases of brakeless emergancy stops....

jamesmartin · Sep 20, 2013

easye1 said:
reading through this thread with its fors and againsts,
must add I "warm" up my handbrake when its cold outside, but only in the lower gears = slow speeds.
another point missed with your comment James,
back in the day (series period) commer vans had the hand brake on its front wheels I believe = interesting Idea In cases of brakeless emergancy stops....

didnt know that would be interesting yanking that on at speed

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