z31maniac

Update to my situation:

ART continues to NOT return emails, so I sent a quick note to Flyin' Miata. They are replacing the hub on their own, so of course a big thanks to them for their continued customer service.

However, I think going forward, I'm just going to buy OEM and keeps spares. Not even bother with rebuilding them and just change them when they fail.

Leafy

iTrader: (1)

On the a similar note to this thread.

Repacked rear bearings saturday. You do it the same way as the front bearings, like almost exactly the same way. There's not write up for it, but you can figure it out. One thing I did find is that the cheap bearing use a different style seal than the OEM bearing and they are not interchangable.

cordycord

iTrader: (2)

Just FYI, there should be another hub option available next year. Right now we're working on front and rear hubs with U.S. made tapered bearings, which are designed to take axial loads and should (in theory) dissipate heat and loads much better than stock.

The hubs right now are only optioned with 70mm endurance studs (12.9 grade). It wouldn't be an issue to ship the hubs with the studs not installed, just in case someone wanted to install standard-length studs.

The supplier is an OEM Tier 1 manufacturer. The cost...less than current hubs.

Any comments or concerns? Would you all prefer 70mm studs installed or separate?

Leafy

iTrader: (1)

Will these come with all the proper install instructions and torque specs? This will be different than the stock dual row dual angular contact ball bearings. And I'm assuming they're going to have a lower torque spec which could cause spindle fatigue failure rather than bearing failure is my only concern.

cordycord

iTrader: (2)

At this point these hubs will look exactly like OEM and would have the same torque specs. The only outward difference between these and stock would be teh 70mm studs. For racing, there should be absolutely no performance advantage. However, the hubs should last far longer than standard ball bearing and therefore be safer.

The bearings are not double-row ball bearing, but U.S. made tapered roller bearings. These have a much, much higher surface area than ball bearing (even double row), which helps spread the load.

Pictures, pricing and test results will follow as soon as they're available, which is to say after the ball drops and the champagne pops for 2014.

Leafy

iTrader: (1)

So these aren't like normal old school tapered wheel bearings where you crank them to a certain torque spec, then back off 1/4 turn then to the nearest cotter pin hole in the spindle?

cordycord

iTrader: (2)

The Miata hubs are the style where the top and bottom cup are compressed, leaving enough room for the bearing to operate normally. No backing off is necessary.

Leafy

iTrader: (1)

Yes I know how the stock hubs are. I've changed enough of them. So I'm assuming from what you're saying is that these will be "non-adjustable" tapered bearings which have shims between the two inner races that set the pre-load So you just tighten the nut on the spindle to the same as stock so you get the same pre-load on the spindle as before and but the pre-load on the bearing is set by the shims between the races. You said these are being supplied by an OEM. Will the pre-load shims be setup for OEM or racing applications, these are typically different. And falls into the "if I'm paying x for this..." category of fiddling.

cordycord

iTrader: (2)

Didn't mean to offend. I've repacked enough old skool Volkswagen bearings to know that you were referencing. The whole idea for the hubs is to have something for the guys with wider tires and more ponies. Let's face it, there's only so far you can go with the Miata spindle size and 4x100 hubs, so if the hubs are being overloaded, they'll fail whether they're heavy duty or not. I'm simply trying to delay the inevitable.

One other obvious point: ball bearings are efficient in a straight line, whereas tapered bearings will take axial loads far better. However, tapered bearings aren't going to give you the gas mileage of a ball bearing...but those are the choices we make for safety and performance.

Not trying to hijack either, so please talk amongst yourselves...

z31maniac

I'd prefer to see a bulletnose ARP stud (and would be willing to pay the extra for it), and have it already pressed into the hub.

That way it can go from box of spares in the truck, to on the car with minimal effort.

Savington

iTrader: (31)

A few quick thoughts for you:

1. Designing hubs for high-horsepower guys is a pretty fatal mistake IMO. High-horsepower cars don't see enough run time to damage the hubs. Design the hubs for the thousands and thousands of club racing cars that actually wear front bearings out.

2. If the studs aren't ARP (not ARP-style, but specifically made by ARP), then I will not pay a penny for them and will prefer to remove them and install genuine ARP hardware.

miata2fast

iTrader: (2)

Our little motors need all the help they can get. Personally, I would prefer the ball bearing style hub and keep my less rolling resistance. We aren't driving 400 cubic inch, 3500 lb. monsters.

cordycord

iTrader: (2)

Bottom line is that I'd be making the hubs for me. I think the benefits they offer would cover most of the Miatas that track. Sure, there are guys who want aluminum and guys who will step up to 5x114.3 and custom uprights, but these hubs will cover the majority of tracked Miatas.

As for the studs, so far there's one vote for installed and one vote for not. FYI, I've ordered and used hundreds of thousands of studs for trucks and off-road racers from my current supplier, and none...not one..has failed.

cordycord

iTrader: (2)

You forgot the main reason why they're used...cost.

I wonder if a change in hubs could even be measured in terms of acceleration, back to back.

miata2fast

iTrader: (2)

I guarantee they can.

Leafy

iTrader: (1)

And IMO a tapered bearing really isnt a good solution anyways, just form cost-benefit. Our hubs most likely come with Grade 100 ***** in them, stepping up to grade 5 would theoretically increase life 10 fold, and going ceramic would easily double that. But just a grade 5 ceramic rebuild in $20 hubs puts the price up to $120/hub + grease. I couldnt find steel grade 5 ***** in my quick search but they're going to be cheaper than ceramic.

cordycord

iTrader: (2)

But I haven't told you the price yet.

Leafy

iTrader: (1)

So what I'm saying is that for it to make sense they need to cost $80 or less each and not drag any more than stock.

cordycord

iTrader: (2)

Yes, it's the "curse of the Miata owner"; where you'll scour a junkyard for a $20 hub, pull it off, clean it, find and order the bearings, replace 'em over the weekend and then say it only cost you $80.

Leafy

iTrader: (1)

And by scoure the junk yards you mean log onto rock auto or ebay.