Doorman rears are still the standard? Just be sure to get the China ones?

Too all!!!!!!!!! Very Important Info!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The Dorman ones that come with the black wheel studs which I think is all you can get now do not take either of the Miata sized wheel studs. They do take Mitsubishi sized wheel studs. The knurl diameter is slightly smaller than the larger of the two Miata sizes.

Confirmed. My Dormans came from Amazon. I found this out the hard way two weeks ago while trying to press in some ARP 100-7720 studs. Ended up reusing my old 1990 hubs and pressed in some ARP 7719's instead.

I'm finally getting around to doing my hubs this year. I pulled the rear hub flanges out of storage (bought them late 2014) and decided to check them after seeing bbundy's comment on the knurl size being off.

Hubs are Dorman 930-550 that I got off Amazon, the knurl diameter of the stud I removed is ~.560-562 and the diameter on the flange is ~.559.

https://www.miataturbo.net/attachmen...ine=1457461706

https://www.miataturbo.net/attachmen...ine=1457461706

That seems very big. I measured the OEM hole last night at .501". And the ARP studs are .507". I just got F-body studs to try out, and those are .509"

.560 is the Mitsubishi stud. OEM 90-93 is .501, but nobody should be putting original 90-93 hubs back on their car. All the replacements I've bought from Mazda have had ~.575 studs in them, which is the larger 94-05 size.

These are 96 hubs. Front. My mistake.

Ordered two Timken 510003 bearings off Amazon today. Are new seals and retaining clips required with these bearings?

Yes

From rockauto:

https://www.miataturbo.net/attachmen...ine=1457466422

Thanks! I'm shocked RockAuto is cheaper than Amazon for these.

I love rockauto. I replaced my upper ball joints and rear hubs, and rebuilt rear calipers, all for pretty cheap.

How appropriate that I came across this thread today! I replaced all four corners in the past month (May 2106) as part of the turbo build on my 243,000(+) mile NA chassis. It would be truly frightening to have this happen during vigorous street driving.

I can confirm this and I wish I had seen this thread prior to buying the Dorman 930-550 hubs. I kept them around too long to return them, so I'll put them on my other 93LE. The ONLY reason this was an issue for me was because I went to the ARP extended lugs on all four corners.

Oh shit. I have new dorman rear hubs and the machine shop just pressed the ARP studs through. No mention if they where too tight. Scrap them or run them?

+1 Don't be like me. Change your hubs.

Oh my god. Glad you where ok.

Dayum! Looks like you lucked out for sure.

Did poo come out?

Snot just came out. And whiskey.

Yeah, that's scary. Over 100mph and didn't tumble.
Kiss your wife, kids, dog, and cat.
If you have none of the above you should kiss someone else's. And call your mom. She misses you. And say a prayer of thanks. And pour one out for a homey who wasn't as fortunate. And ask that girl out you think is above your level. And take some time to just watch a sunset. And take a kid fishing that doesn't have a daddy. And bring something nice to an old widow who doesn't get many visitors. And adopt an older cat who doesn't have a chance. And feed some squirrels because they are bushy tailed rats.

Yeah, I've thanked my lucky stars every day for the last four months. Probably should start playing the lottery.

Ok, now I'm freaked out. Is it the hub or a bearing failure? I have replaced the bearings on my 95, but not the actual hub.

The hubs fail.

--Ian

The hub. https://cimg3.ibsrv.net/gimg/www.mia...559754551.jpeg

Crikey......

Glad you are still in one piece and perceivably the damage was not too extensive.

Glad you are all right Supersuckers!
That is just disturbing to watch!
Jeez!

Holy crap! Stock OEM? Original or have ​​​​you replaced at some point?

That's scary as hell. Can't believe you did not flip. I for sure would have needed new pants. How bad is the rest of the car?

Likely OEM.Car has 60k and ~120 hours track time.

Car is in surprisingly good shape. A little sheet metal damage in the wheel well, frame rail is a little deformed, busted CV boots, a slightly scuffed control arm, and the wheel and tire are toast.

I suspect one thing that helped me is that I had replaced the factory brace behind the diff with a 1x2" piece of steel for greater exhaust clearance. The custom brace is an inch lower than the factory brace and took the brunt of the impact and kept the car a little further up off the ground. Also a great jack point. (Diff pic is post repair)https://cimg2.ibsrv.net/gimg/www.mia...5035c64029.jpg
https://cimg4.ibsrv.net/gimg/www.mia...30d143ca17.jpg

Had you ever inspected it? I look at mine for cracks before every track day... not sure if that would catch it though.

I'd inspect them when I changed the pads. Moving forward I'll replace every season. The juice ain't worth the squeezing if you try and run them longer.

Reading back through. Do we have a part number for the ARP extended studs needed for use with the Doorman larger stud hubs.

And should wheel studs be replaced with hubs? I assume so, but figured I'd ask what the norm was.

According to Bundy, it appears to be 100-7717. looking through the specs of the stud they look right for the reported changes in the Dorman hub. I'll be purchasing both shortly and follow up.

Yes. worst case is you spent an extra couple bucks for no reason.

Ok, so I just bought a few of the Dorman 930-550 rear hubs from Rock Auto for around $15/ea.
They are made in China.
https://cimg4.ibsrv.net/gimg/www.mia...030cdae84d.jpg

They are drilled with a ~0.552" hole for the wheel stud.
The closest 'murican drill sizes are:
35/64=0.5469
9/16=0.5625
The closest metric drill size:14mm=0.5512
https://cimg7.ibsrv.net/gimg/www.mia...e88697cd35.jpg

I then measured the knurled diameter of the original stud to be 0.571"
https://cimg1.ibsrv.net/gimg/www.mia...bccd14164b.jpg

These are the ARP wheel studs which are specified for the 94-05 rear.
https://cimg2.ibsrv.net/gimg/www.mia...bc7ab85694.jpg

ARP says they have a 0.579" knurl diameter, so that means I can measure good.
https://cimg5.ibsrv.net/gimg/www.mia...4003030fb9.jpg

I really don't know what size stud they should be.
The ARP 100-7717 has a knurled diameter of 0.565", which is 0.006" smaller than the original studs. The 100-7720 is 0.008" oversize.
I had no issues installing the 100-7720 with my hazard fraught ball joint press. Either will fit in the end. I didn't see anything in the machinist's handbook about press fit with knurling, so I'm not sure if it functions the same as a standard interference fit joint or not. I don't know how to measure the inner diameter of the knurled stud, unless I cut a stud in half so I can get the calipers on it.
Anyone want to start cutting studs in half to measure for the good of the internets?

I looked on the ARP site and the only sizes are 0.565 or 0.579/0.580, so take your pick.

Meh. I just run whatever studs come with the hubs.

When I called ARP to ask about mis-sized holes on front hubs, they recommended that the major diameter of the knurl should be .005 bigger than the ID of a round hole. Not sure how that applies to a measurement taken off a hole that's been deformed from previous stud installation.

Once you add spacers and aluminum hats (which are a few mm thicker than stock steel rotors), there aren't many threads left on a stock stud.

--Ian

I'm not certain, but I would expect that properly-sized studs are sized to keep the hub in the elastic deformation zone (ie, will return to original shape when you pull it out). Once you get into plastic deformation, the strength drops.

--Ian

The (front) hubs I've seen have all had visible ridges from the knurls of the original studs after they were removed.

I'm not saying the hub is changing shape and stretching out, just an indentation, so the necking phenomenon past yield in a tensile strength test wouldn't apply.

I am interested to know how many rear hubs rock auto has sold in the last two weeks because of this video. I know I got a set.

Do you guys always replace the bearings at the same time?
That was scary indeed...

I always do. I don't think it is possible to press the hub out without trashing the bearings, but maybe?

No offense, but I would throw those hubs and studs in the trash. Hole diameter is .551, press-fit is .005-.008, and you pressed a .028" oversize stud into a part which is already known to be weak enough to require regular time-out intervals. Way, way too sketchy for me.

The Dorman Taiwan hubs have the proper rear hole size. The China hubs do not. If you are replacing studs, IMO, you have to start with US or Taiwan hubs.

How do you make sure you get the non china doormans. Different PN?

What does Mazda supply if you order from Mazdacomp?

--Ian

No idea never tried.

They want $94 a side without wheel bearings. Curious what manufacturer they use.

I make sure I get non-China by shelling out for hubs from Comp. The price tag sucks but I just don't have time to mess with it.

Interesting. Didn't know that mazdacomps were from doorman. Good info. Thanks.

I bought the OEM ones through Mazdacomp when I did mine a year or two ago. From what I remember, they came sealed in a Mazda bag and didn't have any manufacturer markings other than Mazda. I don't think they were made by Dorman. ARP studs pressed in easily.

If I use standard interference fit clearances, such as you listed, then even the stock studs are the wrong size on the Dorman hubs. I'm not a design engineer or machinist and have found nothing online about clearances for interference fit joints with knurling. Hopefully we can come up with a cheaper solution than buying OE replacements from Mazda. I can buy a stack of Dorman hubs and get them reamed at the machine shop for less than 1 OE part.

Look at the geometry of the knurling on the Chinese stud (it's not an OEM part, I promise you) vs. the knurling on the OEM stud. Totally different. The Chinese stuff works together, but you yourself said that ARP wants .008" and you had 3x that. No bueno.

I can't see any problems with reaming Chinese hubs to the proper dimension, so long as the geometry and metallurgy of the rest of the part is adequate.

If you have the reamer sitting around and your time is free, maybe.

--Ian

Drilling and reaming 4 holes is worth $80 to me. I'm not on that bay area salary life though :D

At $94 vs $15 per part, it's $20 per hole. If you have a local machinist near your house/work, it may actually make sense.

The reamer will probably cost you $30 -- how many holes is it good for before you have to throw it away?

And I suspect Savington's labor rate is high enough that it's not worth his time. :)

--Ian

Thats not the first time i've heard that around these parts

https://cimg0.ibsrv.net/gimg/www.mia...a26275f841.gif

Chinesium reamer vs chinesium hubs. If I did hubs every other year. And reamed 8 of them I bet I could go 10 years on one reamer.

I went with Madza comp hubs, for a couple of reasons. #1, guaranteed to work. #2, guaranteed to work.

Pictured also are lovely Madzacomp brand new rear knuckles. Why? A couple of reasons
a) original uprights with this car are 180k and no ABS. I am installing ABS. For those not in the know, this requires new uprights all the way around, unless you possess mad machining/fab skills not available to mw, The mounting points for the abs sensors are not machined on the non abs uprights.
b) used rear abs uprights are problematiic. How many miles do they really have? I purchased some, and they came with bearings and dust shields, but the rust factor was real. For a track car seeing 2x+ oem power, I questoned them. Also one of the dust shields was bent during shipping, not the fault of the seller, but. But. My experience with separating 100k+ mile rear knuckle components is bad, here in the salt free NW. I didn't even contemplate trying to take the bearings and dust shield out of those uprights. So I just bought new.

For your internet amusement: New Uprights (w/bearings, as MazdaComp ships them), new rear hubs. Deadblow Hammer. Win. As with so many things, apply lube and hammer it home. The pipe products pictured are 1-1/4". Floor adapter, nipple adapter, joiner. 32mm socket.


https://www.miataturbo.net/attachmen...1&d=1490159215

https://www.miataturbo.net/attachmen...1&d=1490159215

https://www.miataturbo.net/attachmen...1&d=1490159215

https://www.miataturbo.net/attachmen...1&d=1490159215

https://www.miataturbo.net/attachmen...1&d=1490159215

I went the Rock Auto way, in regards to the hubs. Dont get this one:This one had teeny tiny holes for the stud, listed through all years. Im done messing around, calling mazda now.

so whats the difference with the ABS vs non abs hubs? From my local dealership, the non abs are $30 more expensive. $130.00 each yikes!

There shouldn't be any difference on the rear. The ABS ring is on the axle.