cordycord

iTrader: (2)

This project is deeper than my pockets, as the FEA testing costs more than a good used NB. I partnered with FM as Bill Cardell is literally rolling in cash up in Colorado. You ever see those game shows with the booth that blows money around? Bill literally has a basketball court like that.

Edit--heavy sarcastic humor. I'll be selling them too, but i'm just not the sales juggernaut that FM is so they'll see the lion's share of sales.

k24madness

iTrader: (6)

I look forward to these. Thanks Cord!!!

cordycord

iTrader: (2)

Don't thank me yet...there's still lots to do!





Check out the bump plot. So far the bearings just don't come into play.

k24madness

iTrader: (6)

First you tackle the extended lower ball joint project. Cleanest solution for additional camber yet!

Now you're going after the Achilles Heel of the Miata.

I'd say that deserves a big thanks!

GraemeD

iTrader: (1)

Excuse the dumb question, but in bump wouldn't the load be distributed between the bore of the wheel and ALL the wheel studs? It appears that the force is applied to only one wheel stud. But if one stud can handle the load then the rest is gravy.

acedeuce802

iTrader: (1)

The load should be distributed across the hub face and the hub bore (if the hub bore is toleranced correctly, otherwise it would just be the hub face). The studs shouldn't really take any force, but only provide clamp load.

bbundy

interesting for the 323/ protégé Mazda went from tapered roller bearings to ball bearings and durability went up an order of magnitude. I've had significantly better luck with cars with ball bearings and rolling resistance is also significantly lower with *****.

bbundy

Exactly the software I use every day although most solving is done with Abaqus.

acedeuce802

iTrader: (1)

Ball bearings are overall better than tapered roller bearings, but they have to be setup right. Ball bearings cannot withstand axial force or moments, which is why two bearings must always be used in a wheel bearing application. The further spread apart, the lower the moment. The larger the bearing, the lower the moment. Our bearings on the FSAE car are 90mm ID and spread ~60mm apart.

We actually used angular contact ball bearings, which when oriented properly (clocked the right way, spaced out properly with respect to the diameter) they can react load efficiently in pretty much all directions.

jmann

Cars up until sometime in the 60's had ball bearings front and rear and it used to be a regular maintenance issue. We used to replace alot of them back in the day at my grandfathers garage. Since going to tapered rollers up front and flat caged or tapered in the rear they last forever, I can't remember the last time I had a wheel bearing fail except on a trailer which had ball bearings. Now most on here aren't old enough to remember the good old days but I well take a tapered roller any day over a ball bearing for longevity.

Mobius

iTrader: (2)

In. Thanks Cord!

bbundy

Tapered rollers are suited to High loads but not so much high speed. Friction and bearing temperature rise is much greater with them. They are well suited for a heavy *** lumbering truck hauling a load 60mph on 43" OD truck tires but not real well suited for a car running 120mph on 23" OD tires like a skate board for comparison.

Kind of like Bias ply tires. Sure the load rating is high but try to pull them loaded at freeway speeds and they overheat and delaminate.

Results may prove me wrong but it goes against my engineering knowledge.

I have never seen a trailer axle with ball bearings and I have been through just about every supplier of trailer axles and hubs catalog. I've seen tons of trailer wheel bearings fried, all tapered rollers.

jmann

I raced corvettes for several years at high speed and can't remember having a bearing failure running tapered bearings. I would be willing to bet there are alot more cars by a boat load on the tracks with tapered rollers then ball bearings. I ain't no engineer, just going by what seems to be the bearings of choice by most pass. and race cars.

patsmx5

iTrader: (16)

Yeap. You should have a wheel bolted to that hub in the model (torque at fasteners, etc) , and apply the loads to the wheel and then see what it does. IE simulate a load the way it's actually going to be applied if you want to predict the stress/deflection accurately.

Leafy

iTrader: (1)

Stock miata hubs use angular contact bearings, two of them. same for the rear. We ended up using what I later found out to be stock miata rear bearings on the front of the FSAE car one year. Of course we paid taylor race a nice 4X markup on a $20 bearing because it said formula car on it and we didnt know any better.

The thing that taper roller bearing hubs really get you is the ability to take a shim out of the shim stack and crank ye ol nut a bit tighter to get that last session in on a set of bearings that are 90% of the way fucked. Of course if we didnt have modern manufacturing tolerances and wonderful engineering the miata would also have some shims to set the bearing clearance on their angular contact bearings. I'm with Bob, leave the tapered rollers on your trailer. Unless you cant possibly package a set of ball bearings in the miata hub. What is nice though, he do have the room to go with a larger bearing on the outer than the inner on the miata hub and the outer takes the most axial load in cornering.

bbundy

Since 1984 all corvettes have angular contact ball bearings in the front and rear hubs C4 C5 C6 and C7. Going on 32 years now with ball bearings. Your age is showing.

Leafy

iTrader: (1)

And thank god for that the C4 and 4th gen F-body hubs fail even if you place race tires next to the car.

jmann

I guess the "engineers" that designed the porsches, aston martins, audis and the majority of other race cars were wrong in their choice of bearings, and I do know how to pack the miata hubs.

jmann

Those are a lot newer then what we were racing and it does look like they have gone to a hub asm. which probably has ball bearings. C4's weren't real corvettes.

bbundy

Modern Porches, Astin Martin, BMW etc all ball bearings. I can look them up at rock auto. Most anything resembling a modern sports car for the last 20 years or more has *****. Trucks and SUV's however.