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-   -   When was the last time you changed your rear hubs? (https://www.miataturbo.net/race-prep-75/when-last-time-you-changed-your-rear-hubs-72613/)

hornetball 03-21-2017 03:57 PM


Originally Posted by bigben (Post 1400135)
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?

Savington 03-21-2017 06:08 PM


Originally Posted by engineered2win (Post 1399721)
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.
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

These are the ARP wheel studs which are specified for the 94-05 rear. ARP says they have a 0.579" knurl diameter, so that means I can measure good.

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.

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.

aidandj 03-21-2017 06:10 PM

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

codrus 03-21-2017 06:26 PM


Originally Posted by aidandj (Post 1400282)
How do you make sure you get the non china doormans. Different PN?

What does Mazda supply if you order from Mazdacomp?

--Ian

aidandj 03-21-2017 06:29 PM

No idea never tried.

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

Savington 03-21-2017 06:46 PM

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.

aidandj 03-21-2017 06:47 PM

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

jpreston 03-21-2017 06:48 PM

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.

engineered2win 03-21-2017 06:50 PM


Originally Posted by Savington (Post 1400279)
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.

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.

Savington 03-21-2017 06:55 PM


Originally Posted by engineered2win (Post 1400297)
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.

codrus 03-21-2017 07:18 PM


Originally Posted by Savington (Post 1400298)
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

aidandj 03-21-2017 07:19 PM

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

Savington 03-21-2017 07:28 PM


Originally Posted by codrus (Post 1400303)
If you have the reamer sitting around and your time is free, maybe.

--Ian

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.

codrus 03-21-2017 07:30 PM


Originally Posted by aidandj (Post 1400304)
Drilling and reaming 8 holes is worth $80 to me. I'm not on that bay area salary life though :D

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

aidandj 03-21-2017 07:34 PM


Originally Posted by Savington (Post 1400307)
it's $20 per hole.

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

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

aidandj 03-21-2017 07:37 PM


Originally Posted by codrus (Post 1400308)
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

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.

Mobius 03-22-2017 01:10 AM

5 Attachment(s)
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

ryansmoneypit 03-24-2017 02:58 PM

I went the Rock Auto way, in regards to the hubs. Dont get this one:
DURAGO 29595035 Info
Rear
This one had teeny tiny holes for the stud, listed through all years. Im done messing around, calling mazda now.

ryansmoneypit 03-27-2017 03:13 PM

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!

jpreston 03-27-2017 04:11 PM

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


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