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Miata guys - wheel bearing/hub question


Chappy
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I see see all over the net where guys are saying they need replaced/serviced frequently.  I’ve ran the Miata in 5 races now (64hrs of racing) without touching them.  I’m anal about checking for loseness and drag after each day/race and havent seen any concerns.  In fact the bearings spin just as easy as they did when I purchased the car.  

 

How often are you guys repacking/changing wheel bearings and hubs?  

 

Thanks in advance!

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I’m getting ready to change ours out, not because of a real or perceived problem, but just because I have no idea how much time is on them. 

Im of the opinion that the reason you hear about so many hub problems in SM is the Hoosier. None of the tires we run put anywhere near as much side load on the bearings.

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Yes, the HoHo's put a lot more stress on them.  I also think that the QC has improved on them.  Back before SM was running Hoosiers the Toyos used to tear them up too, lost one after only about 9 hours of run time.

 

Considering their price and the fact you can change one in about 3 minutes, they are just a consumable.

 

Rear hubs are better, but they fail differently.   I've had a couple and seen plenty more where you make contact against a rear wheel and then have a spectacular failure sometime in the next 2 to 8 hours.  It isn't the hub that fails, but the flange the lug studs are pressed through.  Leaves the wheel being held on by the brake pads.

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#30 Miata, We change front hubs every weekend, as we rotate thru 4 sets of them.  2 older sets are test day only, 2 better sets are race day only.

the faster you go, the more it will be a problem.  And more curbs strikes, off track etc, the more to watch them.  Add more tire or wheel or offset, more prevelant the issue...

it will be an issue for you at some point, your question is when, and that could be in 100 track hours, or 2...  To many factors to tell...

Used to use redline CV2 to repack.  On redline, it took us 5 front hubs to finish the 24 hrs of buttonwillow in 2nd place, 4 failures, each around 10 hours.  Also had one fail at Vegas overnight 13 hr.  Since switching to Amsoil Dominator grease, we have run several hub sets over 36 hrs with no on track failure.

    With redline, failure mode  was galling of an inner bearing race, which rocking top and bottom of wheel will show you..  Another failure mode is the balls cracking as the hardened layer seperates, which does not show as wheel play until several balls are gone...

 

check closely the inner lip seal when repacking grease in a hub, the seal dying allows grease out or brake dust in, both very bad...

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We used to run daisies and no spacers and the fronts would go a couple of seasons without issue.  Now we run 245s on 9s on the current build and I feel like two weekends is the max.  I had one fail catastrophically on a previous Miata and had to replace every bit in that corner.  It was ugly.  Preventive action is advised, don't wait until they go.  They are cheap, add a little grease and consider them a wear item.  BTW I stopped investing in expensive ones, they seem to wear just as fast on my cars...

Edited by Jer
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After we switched to 245 on 10" wheels we are going about 32-35 hours on front hubs and that is with a clean and repack after 16 hours.  Considering the number of failed hubs we see at every race this works for us and isn't a major monetary investment compared to switching to the fancy hubs or doing a BMW hub swap. 

 

Now if I could figure out what to do with the ten or so sets of old hubs hanging around the junk box.

 

Edited by dvot
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1 hour ago, dvot said:

After we switched to 245 on 10" wheels we are going about 32-35 hours on front hubs and that is with a clean and repack after 16 hours.  Considering the number of failed hubs we see at every race this works for us and isn't a major monetary investment compared to switching to the fancy hubs or doing a BMW hub swap. 

 

Now if I could figure out what to do with the ten or so sets of old hubs hanging around the junk box.

 

Donate to Champcar for new trophies?

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There is a place selling billet hubs with I think dual roller taper bearings that would last a lifetime on a dump truck.  I think they are pretty pricey though.  Also, I doubt they would be legal unless you could put up a hard argument for safety.  I still think they shouldnt be free though.

 

 

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Thanks for all the feedback!  It sounds like everyone has concerns with fronts, any concerns on the rear other than during contact?  Those aren’t as quick of a fix, I do have two spare rear knuckles assembled for spares at every race. 

 

I have a new set of cheap hubs that I carry in the spare box, I’ll probably put those on for the next race and then repack the ones on the car for spares.  

 

The car is an NA6 running 225 RS4 on 15x8s for what it is worth.

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Rears are difficult to redo, but in my experience rarely fail and give you lots of warning when they do.  I plan to do these once a season (four race weekends) regardless.  

 

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7 hours ago, Jer said:

Rears are difficult to redo, but in my experience rarely fail and give you lots of warning when they do.  I plan to do these once a season (four race weekends) regardless.  

 

We have been doing 2 seasons on rears.  That was when they went bad so I would think that yearly is a good idea.  We dont have the tools to do it (need a press) so we pay I think $150 including the parts to have it done at a local shop.

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Just now, Alchemy Autosport said:

We have been doing 2 seasons on rears.  That was when they went bad so I would think that yearly is a good idea.  We dont have the tools to do it (need a press) so we pay I think $150 including the parts to have it done at a local shop.

I pay a little more to do a set.  Even with a press, the rears are tough to do.  The race comes off the bearing and it's damn near impossible to get off without damaging other things.  It's the one thing I have chosen to farm out.  What a PITA.  

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If the issue is load related failures of the wheel bearings, you might consider what grease to use.  On our SAAB 900 front wheel bearings were a problem.  I started to repack the bearings with Lubrication Engineers 3752 grease which our shop at work had used with great success to vastly lengthen wheel bearing life on test vehicles.  End result, front bearings would go well beyond 100 hours of racing...This grease is quite tacky and highly water resistant so it is great for boat trailers too.  

Edited by oddcarnut
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14 minutes ago, oddcarnut said:

If the issue is load related failures of the wheel bearings, you might consider what grease to use.  On our SAAB 900 front wheel bearings were a problem.  I started to repack the bearings with Lubrication Engineers 3752 grease which our shop at work had used with great success to vastly lengthen wheel bearing life on test vehicles.  End result, front bearings would go well beyond 100 hours of racing...This grease is quite tacky and highly water resistant so it is great for boat trailers too.  

Agreed that grease is a huge part of this.  Hence @WilsonSteele s response about the Amsoil Dominator that we use.  Its cost reasonable, at roughly $14/tube, vs some of the crazy racing grease like Swepco which gets pricey and I havent heard much about it being any better.

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Running 205 tires, we have never had an issue.  We do repack and check constantly.  The minute we went to 225's we lost a wheel at the end of a race.  The rears last forever.  It is only the fronts.  Buy the cheap ones and swap them every race if you run fat tires.  If you go to REALLY wide tires, your on your own, but I have seen others have issues even with the expensive hubs.  Miata hubs were designed for 195 tires....

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