54 replies to this topic

[bones240z]

Has anyone experienced more hub failures at 30mm offset vs. 25mm offset?

[Jim Drago]

Has anyone experienced more hub failures at 30mm offset vs. 25mm offset?

I think hub failures have increased with extra grip of the Hoosier, but the offset has not had much to do with it.
Jim

[davew]

I think hub failures have increased with extra grip of the Hoosier, but the offset has not had much to do with it.
Jim

 

Agreed

 

Dave

[AW33COM]

Has anyone experienced more hub failures at 30mm offset vs. 25mm offset?

 

I don't think anybody monitors hub failures by offset in Spec Miata, so it's difficult to say.  Mazda Miata suspension was build around offset of 45/40 (offset is selected at the factory based on the type of bearing/hub you're running in order to distribute the load evenly across that very bearing).  We reduce the offset to 25 for racing. 

 

In general, it is true, the smaller the offset the greater the load (at an angle) on the bearing.  In reality though, the difference is very small, and much smaller in motorsports as comparing to grip in tires and etc.  Maybe some college student should calculate for us the loads based on tire/offset combination.

 

Having said that I still believe the failures we are seeing are due to improper bearing installation (incorrect repacking, over torquing the hub nut, over torquing the wheel nuts, etc). 

[DrDomm]

Having said that I still believe the failures we are seeing are due to improper bearing installation (incorrect repacking, over torquing the hub nut, over torquing the wheel nuts, etc). 

 

...and what are your recommendations to prevent such failures.

[Jim Drago]

I ran the same set of hubs on Mine, Sandlins and Berrys cars all year, They were installed for last years Runoffs. Doing the same now. One of mine has very little play, the other five have no issues at all. We run about as much as anyone IMO

Jim

[Bench Racer]

Having said that I still believe the failures we are seeing are due to improper bearing installation (incorrect repacking, over torquing the hub nut, over torquing the wheel nuts, etc). 

And what percentage of hub failures do you attribute to the cheap manufacturing process used for these hubs/outer races? 

[AW33COM]

...and what are your recommendations to prevent such failures.

 

Common sense.

 

 

 

And what percentage of hub failures do you attribute to the cheap manufacturing process used for these hubs/outer races?

 

I don't know, hard to say.  We all knock on cheap manufacturing process without sending out damaged bearings for proper analysis. 

Bearings I've damaged when opened up turned out to be my fault.

 

The riddle is: some can go for years on the same bearings that others do damage in one weekend.  

[Bench Racer]

 We all knock on cheap manufacturing process without sending out damaged bearings for proper analysis. 

There is only one thing that may be said about inductioning hardening outer bearing races within an economy hub, CHEAP. And not originally ment for racing.

 

The riddle is: some can go for years on the same bearings that others do damage in one weekend.  

If one looks at the front Miata hubs as anything other than a perishable item their looking for an issue. One weekend bearings are most likely self inflicted.

[Ron Alan]

And what percentage of hub failures do you attribute to the cheap manufacturing process used for these hubs/outer races? 

To clarify...front hub/bearing is a single assembly. Different factors going on here with potential for different types of failures. I'm going to guess the bearing justs get sloppy most often. Anyone seen the hub separate into 2 pieces?

 

Rears...the hub presses into the bearing which is pressed into the knuckle. Hub, bearing, knuckle...3 separate items. I guess you also need to include the axle in this equation!

 

Bearing failure...seen this!

 

Hub failure...seen this!

 

Knuckle failure...never seen

 

axle failure...seen this(sheared off at the nut.)

 

Many warned of the extra stress the R-compound was going to have on these parts! Is this what a lot of you fast guys are experiencing?

[Keith Andrews]

I can only offer anecdotal input.  I've used the same left front bearing for 20 weekends that usually include a test day and the Majors this year have generally been 4 day events.  The right front 1 year roughly 10 weekends.  I clean and repack the front bearings about every 3-4 weekends.  All this has been on Hoosiers.  I used to do the rears once a year but now I just go until failure.  No rear failures this year.

 

I also have removed the metal seal on the new bearings when the rubber seal underneath it starts coming apart.  I replace it with the old style rubber seals that Advanced sells.  So far I have had good luck and no issues doing this.  It just extends the life of an otherwise good bearing.  

 

I only used the Toyo's for one year. 

[Bench Racer]

To clarify...front hub/bearing is a single assembly.

 

Different factors going on here with potential for different types of failures. I'm going to guess the bearing justs get sloppy most often.

 

Anyone seen the hub separate into 2 pieces?

Thanks for the clarification, would have never known without your input.

 

So if the "bearing gets sloppy", you words. Is it the inner race, the outer race or the balls. With my minimal experiance compared to prep shops I have never viewed an inner race failure. I have never measure the balls after a bearing failure.

 

I have viewed the inductioned hardened material of the outer race peal away from the parent material. 

 

Side note for those taking notes:  

 

With production calss cars they typically use 30mm offset wheels along with 3/4 to 1 inch width extender spacers. Don't know the comparable hub filaure rate to the Spec Miata. At Fridays Road America test day with a production class car we had a front hub that was only three race weekends from new show the start of failure. We changed it before failure. It was torqued to approx OEM spec, had a slight bit of top to bottom movement and could feel a slight roughness at slow hand rotate/feel. 

 

The prep shops have plenty of data. The stay out of these on line pi$$ing matches. 

[Ron Alan]

David...clarification was for those who maybe are new and learning. You and I both know if someone says "hub" failure...this can be different things entirely. How did this thread go form steering wheels to race failure??

[Jim Drago]

Most all failures we see are the outer race. 

[Bench Racer]

David...

 

 

 How did this thread go form steering wheels to race failure??

 

 

Has anyone experienced more hub failures at 30mm offset vs. 25mm offset?

 

  Tangent>>>>>>>>>>>>