VCCA Home Forums GENERAL DISCUSSION General Discussions Dominant Driving Wheel(s)

I have come to understand that the right rear wheel on our old Chevrolets (and other marquee's as well) is the dominant (driving wheel). That is to say that it is the dominant wheel when going down the road on even pavement. That the spider arrangement in the differential only acts when something causes it to come into play such as a curve and differences in dips and/or bumps in pavement in which case the left merely lags behind the right and visa versa. Otherwise the left rear is just along for the ride and isn't doing any work other than keeping the brake flange from scrubbing the pavement.

Question:
a. Why is the right wheel dominant over the left and thus doing almost all the work?
b. If the engine turned right instead of left, would it cause the left rear wheel to be dominant?
c. In a limited-slip arrangement, is the right wheel still dominant?
d. What about four wheel drive, is there only one wheel dominant at a time? Or is it two? I think only one.
e. In the movie, "My Cousin Vinney", was that just Hollywood stuff about the two scratch-off tire marks on the highway owing to limited-slip differential, or what? Seems to me there would have still been just one tire burn streak and the only way to get two (of equal leavings) would have to had a lock-up arrangement of some kind.

I do not know the answers to the above questions. (Even if I did, I wouldn't say so.) I hope you all can straighten me out. (I need a heap of that.)

Best, Charlie

Theoretically, the power is distibuted equally to both wheels, until one wheel encounters a traction problem, then that wheel spins.This is with out a traction lock or posi rear. The reason that the right tire spins easier than the left is that in a high load situation,(hard acceleration) the rotation of the engine is trying to twist the rear end housing the same way as engine rotation, thus lifting the right side tire and putting more weight on the left. If the engine spun the other direction it would lift the left and plant the right. Drag racers often preload or adjust the suspension to compensate for this.

Many different arrangements for the 4 wheel drive and all wheel drive. To many to go into, but most 4 wheel drives will spin 1 front and 1 rear tire when stuck in the snow,whichever one has the least amount of traction, unless they have a posi differential.Hope this helps. I am sure others will weigh in.

When I had my 68 Caprice (with limited slip), if you tried to "burn out" it would "fish tail" as traction shifted from wheel to wheel. I never could get it to do that on clean dry pavement, but did on wet.

Good explanation 61 vert. Makes good sense. I have had 2 vehicles with posi and liked them with the exception that if starting from dead start and turning, front end wanted to "wash out" as posi would act as lock and both rear wheels pulling together. It happened on both concrete and on my lawn at home. Doesn't if have to do with weight also as you eluded to. If weight the exact same on both rear wheels, if you could figure that with the torque applied, than I would think that a non posi rear end would act more like a locked rear end with both wheels pulling equally. Even with the weight of just driver on left side, doesn't that contribute to more traction on left wheel vs right wheel? Using motorcycle theory, the "jacking" of the rear end with shaft drive is the pinion gear trying to "climb" the ring gear under acceloration causing lift of the rear of bike and squat as its de-accelorated. I'm just thinking aloud here, but theory based on my personal observation of having 4 wheel drives stuck, the wheels spinning both front wheel and rear, the wheels with the least traction will spin out. Thinking here of the weight thing only. Posi is supposed to transfer traction to the wheel not spinning to move vehicle. If there is enough power applied with speed, than transfer of traction between rear wheels to cause both wheels to spin, than the transfer would be done fast enough to cause rear end to sway from side to side on slippery surfaces and less sway on good solid surfaces. Did I just agree completely with you or is weight a contributing factor to this discussion??

You sure do know how to make a guy think Charlie!

Jim.

A posi rear differential is designed to lock both wheels together with clutches or in the case of a locker, dogs engage. Then when you go around a corner, the faster spinning tire unlocks the unit.

It all works as long as there is enough resistance to disengage the clutches. If not then the rear end can remain locked causing the rear wheels to break loose.