not really sure if it belongs here, if not move me

today i was driving the RB4 when i noticed that.
step 1: flip ur car.
step 2: acclerate.
step 3: press the handbrake.

u will see that u only lose 50% of the shown speed.

so...that means that the front read 50% and the rear read 50% of the speed?
shouldnt both read the same?

edit: never mind, misread the post.

Maybe it was the differential slowing down the front wheels? Try it with a completely open centre differential - the speedo should stay the same.

Quote from AndroidXP :

Maybe it was the differential slowing down the front wheels? Try it with a completely open centre differential - the speedo should stay the same.

just tried that....
shown speed was 279 kmh, pressed the handbrake until the rear wheels stopped - speedo still was showing 179 kmh.

i forgot to say it, im in neutral whenever i do this.

what i try to say is, when i pull the handbrake it should either go to 0 kmh (reads from the rear wheels) or stay at the same speed (reading from the front wheels).
both reading around 50% doesnt make much sense imo

RB4 does read off front and back wheels iirc. Don't know why. Try for yourself, set the brakes to max and 95% front and drive along with them both locked, then drive along with the handbrake on and both rears locked. You still get an accurate speedo reading.
Maybe the phenomenon above with the upside down car, was caused by the torque split accelerating the rears to a higher speed compared to the fronts, and I can only assume the reading on the speedo is always taken from the fastest wheels at any given time.

No, with a viscous diff, even with a large difference in torque, the front and rear wheels are still connected to each other. With no load on either end (and barring any transient conditions such as letting off the handbrake), they will always be the same velocity. That's the way a viscous diff works.

Or, if one end is spinning and the other is not, their speeds will eventually equalize to the average velocity of all the wheels. This is only with no load or torque on the wheels, though, and only if you use a viscous diff.

With an open diff, the front and rears wheels should be able to spin independently of each other. However, since they're both tied to the engine and its rate of rotation, they will end up rotating at the same velocity, given no load, regardless of torque split. However, unlike the viscous diff, if you stop the front wheels, the rears will continue spinning. There is nothing there to equalize their velocities as long as it's in neutral.

It's too bad LFS doesn't allow for the center differential to be locked. With all three locked differential, it is impossible to only lock one tire.

Speaking of differentials, I was with my friends in their GMC safari, RWD, and an open differential. We had one tire on wet grass, and one on pavement. When we tried to accelerate away, the tire on the grass just spun, and we just barely moved forward. When the right tire came back onto the road, and we did a one wheel, tire-hopping burnout driving away.

Quote from sinbad :

RB4 does read off front and back wheels iirc. Don't know why.

it seems it does, but it doesnt make any sense for me.
why not fixed on one end?
i mean, when u race all 4 wheels are on the track anyways.
is there something "better" when reading from front and back?

Quote from AndroidXP :

Try it with a completely open centre differential - the speedo should stay the same.

shouldnt it double ?

Quote from Shotglass :

shouldnt it double ?

If the speedo is an average from both front and rear differentials, then no.

Maybe it counts both front and rear diff speeds, and then divides the result by two.

Quote from hrtburnout :

Maybe it counts both front and rear diff speeds, and then divides the result by two.

Did you read my post?

Quote from hrtburnout :

Maybe it counts both front and rear diff speeds, and then divides the result by two.

That'd be exactly the same as reading from the central diff.

Quote from wheel4hummer :

It's too bad LFS doesn't allow for the center differential to be locked. With all three locked differential, it is impossible to only lock one tire.

Speaking of differentials, I was with my friends in their GMC safari, RWD, and an open differential. We had one tire on wet grass, and one on pavement. When we tried to accelerate away, the tire on the grass just spun, and we just barely moved forward. When the right tire came back onto the road, and we did a one wheel, tire-hopping burnout driving away.

I call BS.


wheel doesn't have friends.

Quote from Shotglass :

shouldnt it double ?

Well, I assumed the readings to be taken from the input shaft of the centre differential. Guess I was wrong.