274 replies to this topic

[FTodaro]

But, also, how "tall" is the tire on the STL?  if you look at the bearing load diagram, the scrub radius and tire height are direct "multipliers" of loads and moments at the bearing ...

 

My experience has always been that these hubs fail at the outer race of the outboard row of balls.  Is that still the case with the new rash of failures?

 

I have some post-processing ideas we could try, but we need to figure out what the least sucky base hub is that we can start from .... and we need some test drivers that are failing them so often that we will be able to tell we are making a difference?

I will suggest Mike Novak as a test driver, two reasons, he has failed more hubs than anyone i know, and testing is his business. I have been paddocked next to him  and i try to keep him away from my hubs, just in case its contagious.

 

What are we considering a failure?

 

I have two hubs on my car that have a little bit of play in the hub holding the tire at 12 and 6 you can feel some play. I have repacked them and the race is fine, the grease is good, but it does have some play. so far, no failure.

[AW33COM]

I have been around cars and motorcycles since I was about 3.  My father in the 80's used to produce, among other things his own bearings.  Since then I have seen many bearing failures.  99.9% of that was my fault.  I am 100% sure the failures we are seeing is our fault, but it's hard to figure what exactly we're doing that creates those failures. 

 

Therefor, the best thing one can do is delete that "Repack your hubs" document on the forum.  That will take care of 50% of the failures.  There are so many things that can go wrong with that repack process I will not even bother to start.  One think I can tell you, bearing manufactures know way more about bearing grease than all of us combined.   Car bearings these days are a lifetime item, designed for many miles.  A lot of units these day are not "rebuildable", and they are self contained, so that nobody tries to make them "better", as there is no need to.

 

R compound tires, smaller offsets, racing, and etc does cut down on the life of the wheel bearing, but it does not cut it down from 300k miles to 30.  It roughly cuts it down to 10,000 miles.  Therefor any failure prior than 3000 miles puts the blame on the installer.  There are 3 places where we damage the unites:  repacking, putting the hubs together, final installation.  Once you eliminate repacking, all you have to do is install the hubs correctly and you're good to go.  If you lost hubs over a weekend race at NJMP, which is a smooth track, you may as well rethink the way you install those hubs.

 

I know, people will tell you these bearings are not meant for racing, these bearings cannot compare to a Trans Am car, you're driving like a girl, and etc.  Well, let me tell you, I run the same exact bearing (same series from SKF) in my Dodge Viper which has 600hp and about 3300 lbs.  If they were bad, they would fail long time ago.  Those hubs in your Miata are actually (contrary to popular believe) very good.  The plastic part inside the bearing completely does not matter, as it's pure function is to hold balls in place. 

 

There is also one more thing I noticed in club racing, most bearing failures happen in SM, but the same bearings or worse bearings are ran on heavier cars that also run Hoosiers.  Chances are the sole problem is repacking, but that's a wild guess.

 

Whatever you do, eliminate all "customization".  Buy Mazda (Koyo), or Timken (SKF) bearings/units.  DO NOT repack them EVER.  Install them using 165 lbs-ft torque fronts (you may go to 175 with SKF and see what happens), and 185 lbs-ft of torque for the rears.  It has to last for at least one season.   

 

There are many guys on the forum that run the same bearings for years.  Maybe they should post if they repack them or not (forum poll?) and what kind of approach they have.  That way we'll be able to pinpoint the cause. 

 

Building heavy duty hubs for SM will work, because guys will be more embarrassed to admit failure, and the bearings will be successful

But if what you say is true, that you go through 3 bearings over a weekend race, then no type of heavy duty hub will help.  They will all fail.

 

Front - SKF - 170lbs-ft

Rear - SKF -  185lbs-ft

NOT Repacked

Offset: 25

Tires: Hoosiers

3200 miles

[Keith Novak]

Chances are the sole problem is repacking, but that's a wild guess.

 

Whatever you do, eliminate all "customization".  Buy Mazda (Koyo), or Timken (SKF) bearings/units.  DO NOT repack them EVER.  Install them using 165 lbs-ft torque fronts (you may go to 175 with SKF and see what happens), and 185 lbs-ft of torque for the rears.  It has to last for at least one season.   

 

There are many guys on the forum that run the same bearings for years.  Maybe they should post if they repack them or not (forum poll?) and what kind of approach they have.  That way we'll be able to pinpoint the cause. 

 

People have been repacking their hubs for years.  If that is exclusively the problem, it should not be a new one.  If they are using the same hubs, the same grease, and the same repacking technique as always and the failure rate issue has only started to occur recently, it would lead me to believe that something else must have changed to cause the issue.

[Bench Racer]

AW33COM, hate to bust your bubble, there are many F production Miatas with Hoosier tires that have the front hubs as a normal maintance/replace item. I crewed one of the National/Major front runners untill a pro shop took over. Oh the pro shop also has the front hubs as a normal maintance/replace item. I don't know the loads of either the Spec Miata or the Hondas in H production racing with Hoosire tires. A Honda H production car that won three SCCA National championships NEVER lost a front hub bearing, oh and they changed them once a year at best. Being you've been around bearings your entire life, you know case hardening bearing outer races for grocery getters allows the bearing to be smaller and dirt cheap compared to bearings that have real outer races. How many inner races fail on Spec Miatas?   Maybe we need to look closer at inner races.

If we continue to share info openly,  we'll get to the root cause of the bearing failure.   No question in my mind, if we were allowed to redesign the bearing hub/select a bearing with real races the failures would stop. There have been several hub flange failures.

[SaulSpeedwell]

  Well, let me tell you, I run the same exact bearing (same series from SKF) in my Dodge Viper which has 600hp and about 3300 lbs. 

 

The Miata front hub is/was only used on the Miata and other tiny JDM stuff (a.k.a. Mazda 121/Ford Festiva).  My pile of failed/bandsawed/hardness tested hubs from the last 10 years has led me to the opinion that the "off the shelf" bearing set has rarely been the problem, but the cast "hub" that the outer race is machined is almost always where failure occurs.

[SaulSpeedwell]

 

 

What are we considering a failure?

 

I have two hubs on my car that have a little bit of play in the hub holding the tire at 12 and 6 you can feel some play. I have repacked them and the race is fine, the grease is good, but it does have some play. so far, no failure.

 

I'm surprised that some of you are getting as many hours as you are once play has manifested, with or without retorquing.  That doesn't match my past experience, but Mid Ohio is smoother than almost anywhere else.

 

I have caught bearings with play during hot pit stops, that then magically "healed" in the paddock when cold.  Such bearings failed within 1 weekend, namely with spalling in the outboard outer race.

[AW33COM]

^ Bad repacking and bad installation will cause the outer race to fail. 

 

I'm not suggesting repacking is bad in motorsports, but where is the proof the REDLINE grease is better than the grease manufactures use in their lifetime bearings? Also, who on this forum (besides pro painters) knows that cleaning bearing elements in paint thinner/ mineral spirits/etc requires a 20 minute flash out period before applying grease?  Otherwise a chemical reaction could affect the grease itself. 

 

There are a lot of pitfalls when rebuilding hubs.  I'm very curious what will come out of this, but I will be the last person to blame the bearings. 

[Brandon]

AW33COM,

Please read this thread I started.

 

http://mazdaracers.c...ro-hub-failure/

 

These were straight from MSP via UPS and no disassembly was done before installation.

I'm still waiting to hear back from ProParts/MSP on the review of my failed hub.

 

I'll just set aside the blanket comment about people not rebuilding their hubs properly.  

I can equivocally state it takes me at least three beers to complete two pairs of hubs.  They 'air out' long enough.

  

 

L8R!

[FTodaro]

Since we are all speculating, I will give you mine, I think there have been a change In the quality in the hubs being supplied. We do not know the history of the rebranding and repackaging of these replacement parts, but we have been running Hoosiers and off sets for a few years yet we are seeing a recent rash of failures,

I think repacking is more important now than before, inspection, daily is also more important.

If I could Sum it it in a few words, cheap steel and poor processing specifications

[SaulSpeedwell]

Since we are all speculating, I will give you mine, I think there have been a change In the quality in the hubs being supplied. We do not know the history of the rebranding and repackaging of these replacement parts, but we have been running Hoosiers and off sets for a few years yet we are seeing a recent rash of failures,

I think repacking is more important now than before, inspection, daily is also more important.

If I could Sum it it in a few words, cheap steel and poor processing specifications

 

It might be "some of all of the above", Frank.  I'll fess up a little  here - my magic hubs that I "ordered" in 2006 and have since run out of, were NTNs with the "double wide" induction hardening that I know you have seen.  At the time, I sectioned them and hardness tested them against 1992 Koyos.  Hardness in the outer race is only part of the equation, the rigidity and toughness of the hub section is just as critical.  AT THE TIME (<2010), I believed failures were due to insufficient hardness in the outer race, or insufficient "toughness" in the 0.030" or so beneath the race surface.  NOW, I am wondering if rigidity of the hub itself is the issue - specifically the outer race section becoming "bellmouthed" under load.  The fact you guys are getting play and still running the bearings tells me that you are possibly plastically deforming the hub.  Some are retorquing and overtorquing and getting better luck.  That also is a change, and also suggests that the hub is "creeping" permanently.  Still speculation, as I haven't seen a any of those parts .... but "play" in all the failures in the past were always due to spalling in the race, and this quickly degenerated into a grinding, super-sloppy, mess of a bearing.  (Caveat:  We never bothered "analysing" unbranded private label hubs that failed super quick.  We only analysed failed hubs we thought were good to start with.)

 

Anyway, mine were true NTNs that came out of an NTN facility.  The distributor I bought them from is no longer an NTN distributor.  There is zero doubt that the grease specified for this cheap, light-duty, aftermarket, application was NOT a top-of-the-line, expensive, OEM grease.  "We" are nowhere big enough to get our own part number from NTN or anyone else, so I bought all I could afford and repacked them with Infinitec 152.  They were always seemingly bombproof, not just on SMs, but any Miata-based thing we put it on. 

 

The "old" NTN part number changed to a "new" NTN part number since then.  Why?  I have no idea.  Two years ago, Timken 513152 "looked like" the same bearing, including NTN markings, and my customers generally had good luck with those bearings - but I never tested them.  I haven't gotten to the bottom of what happened to Timken 513152 since then, but Timken and Autozone appear to have divorced, and pricing, availability, and secondhand reports on the "appearance" and performance of Timken 513152 has been all over the map in the past 2 years.  I've been busy with everything else, and haven't done anything of substance on hubs.

 

You may very well be right, in that there simply may not be an "OEM Quality" version of the Mazda NA01-33-04X anymore.  This bearing may have simply been shipped off to "Aftermarket Hell" with no engineering oversight at all, whereby unless the Autozones of the world get massive warranty returns on their private-label Duralasts and such, there won't be any reason for anyone to look at one of these bearings failing or bother with improving it.  If Mazdaspeed could get Mazda to lean on THEIR supplier to treat this bearing like an OEM bearing, it might help.  But, realistically, why would they?  For a few hundred units a year?  The bearing wasn't designed for what we are doing with it.

 

Having said that - there may ALSO be something causal in the tires, or the wheels, or the repacking, or the studs, or the torquing, or whatever. 

 

It is mathematical fact that higher offset, shorter tires, less grippy tires, will reduce bearings loads.  I know nobody wants to spend money changing those things, but hubs and DNFs and time spent repacking and replacing are money, too.  I'd love to be part of the bearing solution, but I don't think it will be cheap, and the payback will be a long time away.

 

Here's an idea:  If Novak is the bearing killer, get him some low-mile boneyard bearings.  Have someone "lucky" repack them and torque them for him.  And see what happens. 

[Jamz14]

I repack my hubs when I first get them (usually) and before every race weekend. Just now getting a bit of play in one of the fronts after season a season of racing last year and a couple of races this year. The problem is not repacking. It is as saulspeed says. The outer races suck balls. Little round metal balls.

[FTodaro]

It might be "some of all of the above", Frank.  I'll fess up a little  here - my magic hubs that I "ordered" in 2006 and have since run out of, were NTNs with the "double wide" induction hardening that I know you have seen.  At the time, I sectioned them and hardness tested them against 1992 Koyos.  Hardness in the outer race is only part of the equation, the rigidity and toughness of the hub section is just as critical.  AT THE TIME (<2010), I believed failures were due to insufficient hardness in the outer race, or insufficient "toughness" in the 0.030" or so beneath the race surface.  NOW, I am wondering if rigidity of the hub itself is the issue - specifically the outer race section becoming "bellmouthed" under load.  The fact you guys are getting play and still running the bearings tells me that you are possibly plastically deforming the hub.  Some are retorquing and overtorquing and getting better luck.  That also is a change, and also suggests that the hub is "creeping" permanently.  Still speculation, as I haven't seen a any of those parts .... but "play" in all the failures in the past were always due to spalling in the race, and this quickly degenerated into a grinding, super-sloppy, mess of a bearing.  (Caveat:  We never bothered "analysing" unbranded private label hubs that failed super quick.  We only analysed failed hubs we thought were good to start with.)

 

Anyway, mine were true NTNs that came out of an NTN facility.  The distributor I bought them from is no longer an NTN distributor.  There is zero doubt that the grease specified for this cheap, light-duty, aftermarket, application was NOT a top-of-the-line, expensive, OEM grease.  "We" are nowhere big enough to get our own part number from NTN or anyone else, so I bought all I could afford and repacked them with Infinitec 152.  They were always seemingly bombproof, not just on SMs, but any Miata-based thing we put it on. 

 

The "old" NTN part number changed to a "new" NTN part number since then.  Why?  I have no idea.  Two years ago, Timken 513152 "looked like" the same bearing, including NTN markings, and my customers generally had good luck with those bearings - but I never tested them.  I haven't gotten to the bottom of what happened to Timken 513152 since then, but Timken and Autozone appear to have divorced, and pricing, availability, and secondhand reports on the "appearance" and performance of Timken 513152 has been all over the map in the past 2 years.  I've been busy with everything else, and haven't done anything of substance on hubs.

 

You may very well be right, in that there simply may not be an "OEM Quality" version of the Mazda NA01-33-04X anymore.  This bearing may have simply been shipped off to "Aftermarket Hell" with no engineering oversight at all, whereby unless the Autozones of the world get massive warranty returns on their private-label Duralasts and such, there won't be any reason for anyone to look at one of these bearings failing or bother with improving it.  If Mazdaspeed could get Mazda to lean on THEIR supplier to treat this bearing like an OEM bearing, it might help.  But, realistically, why would they?  For a few hundred units a year?  The bearing wasn't designed for what we are doing with it.

 

Having said that - there may ALSO be something causal in the tires, or the wheels, or the repacking, or the studs, or the torquing, or whatever. 

 

It is mathematical fact that higher offset, shorter tires, less grippy tires, will reduce bearings loads.  I know nobody wants to spend money changing those things, but hubs and DNFs and time spent repacking and replacing are money, too.  I'd love to be part of the bearing solution, but I don't think it will be cheap, and the payback will be a long time away.

 

Here's an idea:  If Novak is the bearing killer, get him some low-mile boneyard bearings.  Have someone "lucky" repack them and torque them for him.  And see what happens. 

I will let mike chime but I already think that is his plan is to run old OEM bearings.

[Jamz14]

I am trying to remember a lot of different comments by people so please forgive me if I am off base due to being old with a faded memory caused by self induced destruction of brain cells.

 

I think Jim mentioned that he recently saw an unusual number of failures at a recent event on his cars. This after Jim has moved to the new Mazda heavy duty hubs that are the same hubs with better balls. I don't think anyone doubts how Drago handles his balls and hubs, so I think it reasonable to assume that the problem isn't his balls, or his procedures. That leaves the races, or an esoteric problem with hub flexion as Mark has suggested.

 

Todd posted lateral G loads from a number of different tires. They all look reasonable and within the expected limit of those tires. However, recently I have seen long and lat G loads that looked unusually high. Long G loads in the .8-.9 range, and lat Gs at 1.6 or so I believe.

 

I believe therein lies the answer. Jim, Mark and others are indicating that the hubs were never designed to be racing hubs. Even with better balls than the rest of us, they are stuck with the same races as they have always been. Yes hub flexion may be the issue, but if so, it will be a long long time before anything can or will be done about it. The problem is the races are poor and the fast guys are getting faster and pushing the cars harder (IMO).

[Bench Racer]

 Yes hub flexion may be the issue, but if so, it will be a long long time before anything can or will be done about it. The problem is the races are poor and the fast guys are getting faster and pushing the cars harder (IMO).

There is a process to eliminate the hub issue. It's called "a safety issue" more so when the hub flange breaks and the wheel says, by, by without the car. Hub bearing failures also cause many DNF (racing costs with zero return) because these cheap a$$ed hubs are ment for grocery getters.     Add up the costs of DNF'S because of hub bearing failures and crash damage because hub flange failure and the cost of redesinged hubs will not financially out of place or off the charts. The first step in the process is, do we have a consenses that we require a safer hub/hub bearings. Second, if we do, we need to in mass (plus 50% of Spec Miata owner/drivers) individually write letters for approval to proceed with a redesinged after market front hub from one source, provided one does not exist. With letters in mass the SMAC or CRB will have a difficult time with their typical, "Thank You for Your Input" .   

[Caveman-kwebb99]

I really dont think letters are neccesary. I think it will take some time and some more failures but eventually something will change, there are plenty on the CRB and SMAC that care about the class and the safety of our racing!  This hub thing IMO has been getting steadily worse, and I dont see it getting better... nobody likes the added cost of going through hubs like water anyway... Have a little faith that people in charge are already thinking about this one.

[RazerX]

Just curious to Saul and others.  If today, you had to order a replacement hub what would you order?  Said another way what is on the consensus on what sucks the least?

[Jamz14]

There is a process to eliminate the hub issue. It's called "a safety issue" more so when the hub flange breaks and the wheel says, by, by without the car. Hub bearing failures also cause many DNF (racing costs with zero return) because these cheap a$$ed hubs are ment for grocery getters.     Add up the costs of DNF'S because of hub bearing failures and crash damage because hub flange failure and the cost of redesinged hubs will not financially out of place or off the charts. The first step in the process is, do we have a consenses that we require a safer hub/hub bearings. Second, if we do, we need to in mass (plus 50% of Spec Miata owner/drivers) individually write letters for approval to proceed with a redesinged after market front hub from one source, provided one does not exist. With letters in mass the SMAC or CRB will have a difficult time with their typical, "Thank You for Your Input" .   

 All true bench. But I am not tearing though hubs at the degree others are and nor do we race SCCA. So no letter will be forth coming. And if and when I ever do start tearing through hubs like others, you guys will be long down the road of complaining about it to whomever will listen and my letter will not be needed. As far as a hub being available. Make the hub open like air filters and plug wires, and some enterprising young person with American spirit will fill the void with a reasonably priced hub that can stand up to the new  loads being put on them. After all, that is what everyone really seems to want. A competion hub. I say that because I don't really hear anyone going with Saulspeeds very reasonable suggestion that we narrow up the track or harden the tires. Everyone says that they want this to be the low cost class that the average guy can compete in, but that is BS. We really want to feel like our cars are full blown race cars to stroke our tender egos and make us feel like corvette racers.

[Jamz14]

What Kyle says!!! Letters are not necessary because the problem is afflicting people that have pull and influence. Whenever a problem hits those people, us that don't can enjoy a coat tail ride to the promised land without expending the effort!! That is what racing is about, maximum performance with the least effort.

[Bench Racer]

 Make the hub open like air filters and plug wires, and some enterprising young person with American spirit will fill the void with a reasonably priced hub that can stand up to the new  loads being put on them.

 

 

After all, that is what everyone really seems to want. A competion hub. I say that because I don't really hear anyone going with Saulspeeds very reasonable suggestion that we narrow up the track or harden the tires.

 

 

Everyone says that they want this to be the low cost class that the average guy can compete in, but that is BS. We really want to feel like our cars are full blown race cars to stroke our tender egos and make us feel like corvette racers.

Point A. Would you like a front hub with  a two row ball cartridge bearing or tapered roller bearings? A mature enterprising person.

 

Point B. A few years ago there was similar issues with the front hubs on the Mazda RX7 in E production, redesinged hub, issues solved.

 

Point C. Move from the Chick car class up the ladder to a class that provides your feel goods, Spec Miata can't be everything for everyone.

What Kyle says!!! Letters are not necessary because the problem is afflicting people that have pull and influence. Whenever a problem hits those people, us that don't can enjoy a coat tail ride to the promised land without expending the effort!! That is what racing is about, maximum performance with the least effort.

No dissrespect towards Kyle, unless he has insider info, don't hold your breath.

[FTodaro]

Just curious to Saul and others.  If today, you had to order a replacement hub what would you order?  Said another way what is on the consensus on what sucks the least?

That is a good question because what is on the box does not always tell the truth about where the hub came from, or who manufactured it. An NTN hub could be NtN parts assembled by a Jobber.

 

I want to find some OEM hubs and repack that is my answer.