Bruce In Philly

Why does Porsche use ball instead of roller bearings in wheel hubs?

First, just to be sure, my 2009 C2S has ball-type no? My 2000 Boxster S had ball type. In my 197K miles on that chassis, I went through one set all around (fronts and rears wore at different rates).

On one of those restoration car shows, I saw they pulled the wheels from a 60s era Chrysler product and it has roller bearings. Why there and not here?

With increased surface area, a roller bearing can handle greater loads and shocks such as chuck holes. If we are paying for superior engineering, why *****?

Peace
Bruce in Philly
(too much time to think... that darn active imagination again... and my old bearings from my Boxster are cool paperweights on my desk)

extanker

well maybe because they have a BIG leftover supply of ball bearings cuz they aint puttin them inside the motor any more i couldnt resist a ims jab.

motopix

"It's all ball-bearings these days."
- Fletch

Sneaky Pete

Don't know but I'm sooooo glad this thread wasn't what I thought it was.

Macster

Just wait.

Macster

Think you are trying to find a problem where none exists.

When I did brakes on my other (non-Porsche) cars I replaced the wheel bearings (the front bearings at least) every time. This is what my mech. buddies advised. The bearings were easy to replace. Just a small drift and a small hammer to drive the bearing race out and then pack the new bearing with wheel bearing grease, slip it in and with a new seal install the hum and tighten the hub to seat the bearing. Takes longer to write it than it does to do it.

OTOH, I've done the brakes on my Boxster a number of times and the wheel bearings, all ball bearings too, are original (save one that was replaced (noisy) at around 80K miles) and all were just fine.

The Turbo too has had its (front) brakes done once and the wheel bearings were left alone. They were just fine.

fnckr

An engineer should respond, but my guess is that a wheel hub must endure force from many angles. A bearing sitting in a curved race might handle those forces better.

Fred R. C4S

Ding.....ding...ding...Winner,Winner, chicken dinner!

Ball bearings can carry radial load as well as some thrust load. Roller bearings only carry radial loads.

Bruce In Philly

LOL! No not at all, I was just wondering about the "why" of engineering choices. Nothing sinister here at all although I can understand why folks may think this given the large amount of trolling here.

Peace
Bruce in Philly

Bruce In Philly

Interesting.... so then I must conclude that the engineering design choices for big American muscle of the sixtys were straight-line performance and Michigan chuck holes? And European design criterion was for curvy roads?

Peace
Bruce in Philly

Wayne Smith

I fear I am confused here. I understand that a straight roller (needle) bearing won't take a side load. But a tapered caged roller bearing will.

I know, caged and bearing should never be linked together!

I had a clutch engaged, flywheel driven, intermittently cyclical machine wherein the flywheel was supported with a ball bearing with grooved races. Over time I found up to .003" of side play that developed. This was beyond tolerance as it affected clutch and brake settings, and stopping times could exceed the safety curtain ergonomic equations.

So I went to tapered and solved the problem.

You can't snug and adjust a ball bearing. Call me old fashioned, but there was a good feeling to putting a wad of grease onto your palm, working it into a bearing, snugging the crown nut, and inserting the cotter pin. Times change.

Macster

There is sometimes more than one suitable or adequate solution.

While I replaced the wheel bearings when doing the brakes in some vehicles, the bearings were not shot. The bearings were replaced because they were easy to replace, and because the old bearings required considerable effort to clean and repack. They had to be removed to clean and then a new seal used when installed.

It was just easier to replace with new. But the tapered roller bearings were quite adequate for the job. I mean the loads my 3/4 ton Dodge D200 4000+ lb pickup -- sometimes with over 2000lbs of machinery strap to the bed of the truck -- put to its front wheel bearings had to compare to the loads my Boxster puts to its front wheel bearings. And even in the Dodge pick up truck I never replaced the rear wheel bearings. They were in the axle tube of the rear end and not exposed when doing the brakes.

Macster

Never bothered to convert any ball bearings to tapered but I rather enjoyed at a primal level the job of packing fresh grease into a new wheel bearing, installing the bearing against a new outer race, fitting a new seal and putting the hub on and using the crown (castle) nut to squeeze the bearing together and setting the amount of free play, then using a new cotter pin to lock the crown (or castle nut) in place.

Even now I get all warm and fuzzy thinking about it.

Wayne Smith

Just to be clear, I never modified a car's bearings. I was referring to some industrial machinery that I was specifying out of South Korea. That change involved casting and milling changes that I would not want to do on a single car!

And I believe you are right ... Castle, not crown, for the common term.

One last note ... "Warm and fuzzy" is a a phrase I use quite frequently as I coach people to take proper care of their equipment. It is good to see someone else use it! An apt description in this case as well.

ralt12

How ironic; Porsche switched from ball bearings to tapered roller bearings in the '50's…..

Wonder when the switch back was ?