Do you need the absolute burliest hub available for your NA or NB? Have a dedicated track car with giant sticky tires, and you're treating lesser hubs like consumables? Here's your answer. The product of two years of R&D (with lots of learned lessons), these hubs use a burly 4150 chromoly body with carefully designed geometry to get rid of stress risers and make the hub as strong as possible (no more runaway wheels). They then add true NSK roller bearings (no fraudulent and short-lived knock-offs), but these aren't trailer bearings - no adjustment or constant fiddling is required. They have very carefully calculated and machined spacers, so you simply torque them. The spacers take into account the proper preload as well as thermal expansion to ensure that everything is just right. They're then carefully sealed with O-rings front and rear (and a second seal in the rear) so the bearings stay nice and clean. Finally, they have long bull-nose MSI Racing studs and a new axle nut. The studs are the absolute best you can get, as they're machined from aircraft quality alloy steel and have a baked-on CT-10 coating with Teflon and Moly. Buy the right hub and buy it once.

How much better are these than stock (or blueprinted) hubs, from a longevity standpoint? In a worst-case situation (extremely aggressive driver, abusive curbs, lots of load from sticky tires and/or aero, etc.), a blueprinted hub could last around 15 hours. In testing - over two years of passing the same set of hubs between five different race teams - there were no failures after almost 100 total hours of use (that weren't due to water / dirt contamination). So we can't apply a per cent improvement since the upper end hasn't been found. While the balls in the stock (or blueprinted) hubs are too small for the huge loads true track cars can generate, these roller bearings are dramatically larger and more capable - it's literally not possible to exceed their ratings in a Miata (over 22,000 lbf of load per hub and 380 mph with 205/50R15s). That large surface area and additional (but not too much!) grease means that the heat is much lower in these bearings. Lower heat = longer life.

For especially abusive cars - particularly if there's any suspicion of dirt or water intrusion - these should be cleaned and regreased every 15-20 hours. That said, endurance teams will use them for an entire race weekend, with 24 hours of use, without having to rebuild them in the middle. While these are well sealed, and even better sealed with the latest version, they're not as sealed as stock or blueprinted hubs - if this is a street car and you're not destroying your stock or blueprinted hubs, you're probably better off sticking with those. These hubs are for those track cars that go through normal hubs like candy.

How do these compare to other options? These are rebuildable, don't use a spindle sleeve to use a bearing with a too-big ID, and don't require any adjustment. The lack of adjustment means they aren't susceptible to improper adjustment (which can kill otherwise great bearings) and don't need to be re-adjusted regularly. If you do need to replace the bearings, you can find them at most auto parts stores (NSK HR303/28C, just be sure they're authentic NSKs).

These are sold individually, you'll need two hubs for one car.

Legal for Spec Miata with both NASA and SCCA - this is the only non-stock hub that's legal. SCCA info is here (GCR p. 567, 9.1.7.3.b.r), NASA here (p. 19, 15.15).

Not compatible with ABS - the body of this hub is bigger, so you can't swap your tone ring over. Bear in mind that this hub is about 1 lb heavier than stock (or blueprinted) hubs per side.

Since the cap that the rotor centers on is aluminum, the protrusion that the rotor centers on is slightly smaller than stock. This is on purpose, as the aluminum construction means the material will grow, with heat, more than the stock iron hubs. We haven't seen any NVH concerns because of this change, through many years of selling these.

For more details and installation instructions, check out the videos below! Note that there will be a tiny amount of play when the hubs are fully tightened - that will go away once the hubs heat up and things expand slightly.

NA (1990-97) : Handling : Suspension components

Mazda Motorsports front hub