final drive design

[rado360]

Any ideas why you couldn't have two tapered roller bearings,one big on left one small on right?Instead of one big ball bearing and small tapered bearing?

;)

[Sully]

Sweet idea! Just think if it got used as a revision/improvement- oh, wait... it might cost $5 more in the MSRP.

It would make a great modification, I think. Any engineers on the forum want to crunch the numbers and let us know which bearings to use.

[AntonLargiader]

The amount of preload required to control backlash with dual tapers might be tremendous, given the load that it sees. IMO the solution is to go away from tapered bearings entirely.

[cjack]

The amount of preload required to control backlash with dual tapers might be tremendous, given the load that it sees. IMO the solution is to go away from tapered bearings entirely.

The new final drive on the 1200s has a grooved ball bearing on the wheel side of the bevel gear and a needle sleeve on the other. Lifetime fill. I'm hoping...
I enjoyed your article "Final Drives" in the RA On the Level. I'm looking forward to the next one on the shimming preload discussion.

[rado360]

after Jack's and Anton's comments I like the idea of no taper bearings,also I go along with Anton that a little play in the setup is better than tight.I wonder how side load is controled on new lifetime setup?

[roy]

With a grooved Ball bearing and a caged needle bearing, how or what controls the crown to spur gear tooth engagement?

Just curious

Roy

[cjack]

after Jack's and Anton's comments I like the idea of no taper bearings,also I go along with Anton that a little play in the setup is better than tight.I wonder how side load is controled on new lifetime setup?

I'm missing where Anton said that, but as for the new drive, the needle sleeve may be tapered. I don't know. There are adjusting "washers" in the assembly that may effect a preload. The specifications for the drive are "no movement". The repair manual I have does not outline rebuilding the drive yet, however there are spare parts available.
BMW specifies a small preload in the present setup (older drives). I think it's .05 to 0.1 mm.

[AntonLargiader]

As for the changes with the Evo Paralever, I think I touch on that in the follow-up article so I'll bow out of the questions until then. :)

[cjack]

I'm missing where Anton said that, but as for the new drive, the needle sleeve may be tapered. I don't know. There are adjusting "washers" in the assembly that may effect a preload. The specifications for the drive are "no movement". The repair manual I have does not outline rebuilding the drive yet, however there are spare parts available.
BMW specifies a small preload in the present setup (older drives). I think it's .05 to 0.1 mm.

I see from the repair manual (later edition) that the backlash is adjusted by the thickness of the shims between the housing cover and the housing. The tooth pattern is determined by the shims between the housing and the radial thrust bearing of the pinion. So no preload looks like and the needle cage is not tapered.