As cursory track prep for our NC2, we ordered Timken RX8 hubs from Rockauto. Stumbled across something along the way. The correct RX8 hub for the NC is with DSC (dynamic stability control). W/O DSC has a different ABS connector and is not compatible. I mistakenly ordered w/o DSC and got hubs with fat 9.9mm thick flanges and bigger bearings. Cool but the ABS connection was wrong. Re-ordered the correct RX8 hubs and was surprised to see that had the same thinner 5.2mm thick flange and 68mm bearing housing diameter as the OEM hubs that came off the car.

I was under the impression that the RX8 hub would have a thicker flange and a bigger bearing than the NC part. Scoured all the images for all brands RX8 hubs on rockauto and they were all the thin flange design like the Timken HA590205 RX8 hub. I get the impression that all the hub manufacturers in China figured out the NC casting fits the RX8 and now use it for everything.

Has anyone here taken measurements off the NC and RX8 OEM or aftermarket front hubs?

Timken HA590205 RX8 hub w/DSC - same dimensions as stock hubs that came of our NC2


Timken HA590906 RX8 hub w/o DSC. Product image on rockauto looked like the HA590205 above.

 

So the RX8 hubs you bought would be zero upgrade from the MX5 ones that just came off?

 

As near as we can tell, with a bunch of measurements, yes. So either the RX8 hub upgrade is a myth or the factories in China that make these are just using NC hubs for the RX8 application.

 

Timken shows a different part number HA590360 for the S2 (09-11) RX8 for the Hub W/DSC
Timken part number HA590205 is for the Miata.
Timken part number HA590096 is for the 04-08 W/DSC and 04-11 W/O DSC

The OEM RX8 HUB uses the same thinner flange as the NC, but a larger bearing.
I've got some OEM as well as Timken and NTN RX8 hubs in the garage I can measure when I get home tonight.
I think the tone ring is the same between the DSC and Non DSC. I haven't checked myself, but you may be able to swap the dust seal/cap on the back of the hub so you can use the DSC sensor.
On further review the S2 RX8 DSC and Miata hub uses a multipole mag ring, RX8 S1 and S2 W/O DSC uses a toothed tone ring. They likely won't change over.

 

Yup. We installed the HA590360 on our NC2 but the body diameter was the same as the OEM and HA590205. I was expecting at least a larger body (bigger bearing) on the RX8 hub. Thus my conundrum.

 

Well, this sucks. I was always under the impression that the RX8 hubs were the easy upgrade for NC's.

 

I've heard multiple bad stories about timken rx8 hubs in the last year or two, including one broken flange (with na/nb style wheel separation) on a relatively fresh hub.

My car came with OEM Mazda RX8 hubs so I haven't had to figure any of this out myself, but I need to do front hubs this year as preventative maintenance. My plan is to just pay whatever Mazda comp wants for a set and hopefully get the good ****.

 

I measured the OEM and Timken hubs I had and they were close +-.5mm to the 73.5mm you saw. They are S1 RX8 so not much surprise there. I couldn't find the S2 hub I had, I must have tossed it already.

Looking at all the pics of OEM DSC S2 hubs I could find online it appears that it uses the smaller bearing the Miata uses.
Unless someone picks up an OEM S2 hub to measure I would assume the S2 DSC bearing in the same as the Miata. Strange that they have different part numbers.
S1 and non-DSC S2 is the larger bearing. It appears Mazda did some consolidation in the parts between the RX8 and Miata in '09 as the RX8 got a revised DSC module that looks to be the same as what the Miata got. Front spindles on the RX8 changed to the Miata spindles too in '09. The non-DSC RX8 kept the same Sumitomo ABS so the S1 hubs carried over for the base model.

I've heard the same thing about Timken S1 RX8 hub being less robust than OEM. Dunno if it's a material issue, poor tolerances or bad grease, but the few reports I saw indicate they only last one or two track days on an RX8. I doubt it's limited to Timken though. The NTN bearings are identical down to the numbers stamped into the face. I'd wager 90% of the RX8/Miata aftermarket hubs come from the same factory in china with the only difference being the color of the box.
On a side note, the OEM S2 RX8 DSC hub (F189-33-04X) is ~$80 cheaper than the OEM Miata hub and ~$20 cheaper than the Timken Miata hub. The Timken S2 RX8 DSC hub is ~$125 cheaper than the OEM Miata hub. RX8 hub may not end up being an upgrade, but it's cheaper.

 

Reached out to Timken. MOQ to make the fatties for the NC was 5,000pcs. Oh well.

Fidgitk, nice intel. Thx

 

Revisiting this..

Digging a bit further, The S1 RX8 has one part number for both DSC and non-DSC, F151-33-04X that's not compatible with the NC ABS connector. It also has the thin flange. The thick flange came with the S2 but only on the non-DSC version. Mazda made the DSC hub for the S2 the same as the NC. That part appears to have always been the same part for both. I can find no evidence that the OEM S2 RX8 DSC hubs had the same thick flange or larger bearing of the S2 non-DSC.

My guess is that Mazda's MX5 cup car builder at the time adapted the beefier S2 non-DSC hubs to the NC by hacking the harness and or ECU. That info got out as "S2 RX8 hubs are an upgrade for the NC". As the aftermarket and Mazda S2 RX8 DSC part number does indeed fit the NC, I'm guessing everyone just assumes they were "better".

So does anyone here have concrete evidence that an NC compatible thick flange/large bearing RX8 hub ever actually existed?

Please prove me wrong so I can track down these phantoms

 

In response to a similar thread over on m.net..

Ordered OEM S2 RX8 DSC hub (F189-33-04X) from Mazda Motorsports. Measured shell diameter (bearing size) and flange thickness against the OEM NC2 hubs that came on our car and the Timkens.
The Mazda S2 RX8 DSC hubs were identical in every dimension to the OEM NC hubs. So the perceived superiority of the RX8 hubs comes from being made in Japan from an OEM supplier, not because they are actually bigger.
My guess is that Mazda sourced NC hubs would be the same level of durability as they are the same dimensions as the S2 RX8 DSC hub.

The takeaway is to only use Mazda hubs made in Japan, no aftermarket.



F189-33-04X S2 RX8 DSC from Mazda


F189-33-04X S2 RX8 DSC from Mazda. Same dimensions as OEM hubs that came off our NC2

 

I'd back up the opinion to stick with OEM no matter what for the front hub bearings, RX8 or NC.
The set of NTN(look identical to Timken probably made in the same factory) S1 bearings I put on my RX8 have a significant amount of play in them after ~1000 miles of street driving. I'm replacing them with a set ordered from Mazda.

 

The OEM RX8 HUB uses the same thinner flange as the NC, but a larger bearing.

 

The aftermarket RX8 hubs do not. So we purchased an OEM Mazda RX8 hub and it also did not. While it's possible the oem Mazda hub had a larger bearing in the past, that appears to no longer be the case. I have not seen anyone post direct evidence that the RX8 S2 DSC hub ever had a larger bearing.

There it does appear to be some evidence that the OEM Mazda hub is better quality and last longer than the aftermarket hubs so for the time being. that still probably the best bet.

 

Reviving an old thread, but I'm running into problems using these exact hubs (TIMKEN HA590360) from RockAuto. Having a slightly different issue however and seeing if anyone else noticed this. I pulled the wheel studs and went to swap in a set of ARP 100-7719 extended studs and the knurled diameter is smaller than the hole in the hub. This is odd to me because this is the second set of wheel hubs I have ordered and the last time they went in just fine into another cars front hubs. Now I'm using the leftover studs from that same package that I ordered a year ago and the brand new set of TIMKEN HA590360 hubs I got 2 weeks ago. The studs do not fit, they are loose, and I mean LOOOSE in the holes of the hub. I am so lost as to why
I will add pictures later tonight

 

Sort of related.. we are developing heavy duty hubs for the NC & ND, front and rear. Much thicker flanges, SCM440 extended studs, high temp synthetic grease, PnP installation. NA/NB versions are in production. NC/ND around mid 2024.

 

Any update on this for NC?

 

No updates. Still on the list, but still not at the top of it - only so much we can do at once.

 

My question regarding the ABS connector for the hub. If the connector is different why not just try running it and swapping the connector ends? The real issue is could see is if the tone ring or magnet inside is different than the NC hub.

​​​​​Has anyone disassembled the bearings to check the internal differences?

 

Following up on this subject. Our Competition hubs for NC and ND are in production now.

Link to thread here or visit our website for details https://www.miataturbo.net/suspensio...4/#post1657547