MR-S Rear Hub Discussion
 

Learned something interesting tonight doing a little research on hubs. Did you know that the mr2 spyder rear hubs have the SAME 26ct spline and diameter, SAME bearing race id diameter (40mm) with .07" thicker flange and overall beefier flange base? Differences are .2" longer spline length in the spyder, .09" longer bearing depth on spyder and .3" forward axle position on the miata hub... this is a perfect candidate to massage in a lathe and possibly offer a beefier alternative to the oem miata hubs. Who wants to try? Yea/nay/nof'inway? It'll be another 5yrs of I try it, lol
Btw, this new spyder hub from autozone was only $20 to play with.
I cut the race off to get the .09" length difference between the 2

Do you need lathe work? I can play...

What year MR2?
Any idea if the front hubs are similar enough to modify and use? Or if they're beefier enough for it to be worth it?
If there is anyone in the Seattle area willing to do the machining on them for me for a reasonable price, I'll give them a shot, especially for only $20 at autozone compared to like $55 I spent on new rears.

Spyder

Keisler drop spindles have an option to use these instead of garbage Miata units. I'd be in for some modified MR-S units, seems more in scope than drop spindles for me.

That's what sparked my interest in looking at the rear hubs off the spyder. I didn't know that the rear hubs were now an option with the Keislers. I have Sav's Keisler drop spindles and the front spyder hub it uses is certainly more robust - but there's no way it'll fit or be modified to work with the oe spindles for the guy asking...
Dropping hubs and oe spindle and axle to my machinist today to investigate further.

I'd be pretty wet if i could end up with MR-S rears and V8R fronts on oem spindles.

Am I to take it that you'll be up for beta testing a set of rears after signing a release of liability form :)

Sure, but i don't drive my car much.

Hrmmm, I could use those MR-S rear hubs. Maybe I'll bug Keisler about them. And by maybe I mean I'm messaging him now.

I will say this - like the miata hubs, I'd only buy oem hubs to mod (at @$170ish ea) unless actual lab testing says the aftermarket hubs are just as strong. I wouldn't mind watching something get crushed... best test would be lateral oscillation vs straight one-way force... which one of my sciencey customers can do.

I love this bar.

Worthless trash post so i can get notifications.

https://cimg1.ibsrv.net/gimg/www.mia...e916d77c7f.png

And that concludes my useless post to get notifications.

Typing is easier than clicking.

Have lathe......and ordered part to play with. This will go well with the front hub solution I'm experimenting with.

I ordered a couple toyota hubs to turn for my car... shouldn't be much if any differences dimensionally between them and the cheap $20 hubs. Why did they put 4 extra holes in the hub?

4x114.3 lug pattern maybe?

Weight reduction

I really think the only downside to this hub, after machining, will be a slight loss in overall spline length in the hub. Nothing I'd worry about unless I was drag racing with monster power to strip them out...

This is a great discovery GeneSplicer! I am not worried about the loss of spline length. If for some reason it did fail at least it's not catastrophic like the way they currently fail.

I run the sticky HooHoo's and would welcome the greater piece of mind these would offer.

That radius on the base is sexy.

/IBSubscribed

So I got one of these on hand now, from my measurements this is what's needed.

The wheel stud knurl OD is .507" so a Miata specific stud will work. A 1mm or .040" shim washer is needed between the bearing and the hub to get the rotor centered in the bracket. Then both the splines and the overall length of the bearing snout will need to be shortened to fit the Miata spline length. I don't have a spare axle to give measurements but this confirms to me that this will work.

I'm - or my machinist - is almost done with a pair of machined hubs. Is gonna work no problem. Best thing is, none of the machining is done anywhere that might effect strength - other than in the splines. I hope to have completed n installed pics soon. Now just to find some extended apr studs to press in. I had trouble finding them for the mr-s front hubs (keisler).
​​​​​

Just use the Miata specific front studs with the. 507" knurl.

Now to press in extended studs and install into my Keislers :) more pics to come. https://cimg6.ibsrv.net/gimg/www.mia...724492f6bf.jpg
https://cimg7.ibsrv.net/gimg/www.mia...022f2093da.jpg
https://cimg8.ibsrv.net/gimg/www.mia...d404715455.jpg
https://cimg9.ibsrv.net/gimg/www.mia...8ca9935a77.jpg
https://cimg0.ibsrv.net/gimg/www.mia...ae51ca9d0a.jpg

Oh yes - as I stated before - miata ARP extended lugs wont work​​​​.
The ID of holes where the mr-s oem lugs came out are .550 (the other 4 empty holes measure .595"), and the mr-s knurled lugs measure .560, Mazda knurled lugs are .580 (.020 too large)... soon as I match up ARP lugs I'll let y'all know... or you could just rock on the mr-s lugs as is (same thread pitch as miata).

Why wouldn't we just use the mr-s lugs as is?

Absolutely so - I just want ARP extended lugs

Try the mitsubishi extended lugs mentioned in the "when was the last time you changed your rear hubs" thread. ARP part #7717 if I remember correctly.

If your machinist is up for churning out a plug and play solution, I'm in for a set, I don't have a local machinist I trust.

He says supply your hubs of choice - he'd do them at $50/hub.

Any word how these have worked on track or even on the street? Any issues at all?

Sorry man - not subb'd to my own thread!
I haven't gotten my Eliminator back from wiring/tuning, but when I do, it's one of the first things to swap in.

So for anyone asking, I don't care if you market these or make them yourself. I left the dimension details with my machinist - so if you want exact dimensions of what needs to be done, just pay him to knock you out two... or break out a pair of calipers and mic it out. It's really not hard to figure out what needs to be done. I'm just trying to throw him a little business since he's the one that did all the hard work. I might have discovered this, but it's a free for all as far as I'm concerned :)
If my machinist doesn't care one way or another, I'll list the specs... yeah, I put money into the discovery - but I got a nice pair of mr-s hubs outta it, so I'm happy :)

Follow up - he doesn't care and has limited time to actually work on this anyway. I'm not interested in making money on this so in the spirit of MiataTurbo, I'll post the specs (when I get them) on the modifications needed to the MR-S hubs for them to work - based off OEM hubs (others might be different).

Stoked!

Awesome, I think i'm gonna try this. Especially since i have a lathe and tools available.

Take my money

Let me practice and ruin mine first.

I have a set right now for Marcus, im r&d-ing. Sadfab will probably be offering these soon enough. Ill probably write up a how to as well.

Very interested in this, timing is perfect since it's time to change the rear hubs on Creampuff.
Did you ever find which ARP studs work in the MRS hubs?

MR2 (00-05 spyder) stud specs- 0.559" knurl, 40mm length, m12-1.50

According to ARPs catalog, it looks like the IS300 studs will work perfectly with lancer and celica studs as a close 2nd. IS300 is 66mm under head length(26mm longer). In my experience with wheel studs, you can go about 5 or 6 thou over sized before the hub will crack from hoop stress, when made of cast iron(GM metric chassis shit I do). Im pretty certain these hubs are all steel, so you could add a few thou to that number I would think, and Im pretty certain the 0.565" knurl diameter of the lancer and celica will be just fine. You can also dril the hubs out to fit whatever stud you choose provided they are a larger knurl and not smaller for obvious reasons.




https://cimg0.ibsrv.net/gimg/www.mia...7740ea9ac1.png

Much excite. My current hubs have only about 10 hours on them including transit time, but the part of me that likes to completely overbuild things eagerly awaits these.

I also plan on making some when the budget allows, so probably mid/late March. Will be able to provide machining services for others most likely. Very stoked!

Y'all making me feel good for actually being interested in something I discovered and that actually contributes to the cause :D yay me
I should have the specs this week, with pics

I believe IS300 arp studs are 0.559-ish.

Edit: I missed Sean's latest post.

You should absolutely feel good, this is a fabulous thing to discover, Gene!

Heres what I got


This is Preliminary!!!!!!!!!!!!!!!

Edit- see post #108 for final drawing

https://cimg5.ibsrv.net/gimg/www.mia...a5c0b9600b.png

Some clarification on "bore C": This only needs to be opened up to fit the mazda axle nut which is around 1.8" OD on the flange, the ID of the hub bore is 1.765". A spacer/washer needs to be used under the nut since the splines stick out past the seating face, and so that the locking tab of the nut ends up where it should be. There is a really healthy chamfer at the bottom of the bore where the nut would seat, and since you have to make a washer anyway, you can either:
1. Make the washer OD small enough to fit inside the chamfer so it seats flat, which is 1.600" max. Then you only have to bore as deep as the nut flange sits, about 0.250"
or...
2. Bore all the way down to the face to whatever ID you desire granted its larger than ~1.820" but less than 1.965"ish, and make the washer whatever size you want to fit in that ID. It looks like genesplicer's machinist did the latter and maybe even press fit the washer into place, which I think is a great idea.

With this configuration the wheels will be pushed out 0.038", or just less than 1mm.

Also, the alternative wheel stud pattern on the mr2 hub is indeed 4x100, and the IDs are ~0.589".

Excellent, thanks!
I'll order a set today, been meaning to replace the hubs before SLB and ran out of time, at least I'll start this year fresh :)

I am pursuing making a batch of these as well, have a date with a machinist this afternoon. I haven't gotten final measurements yet, but it appears that there might be some slight differences in the mr-s hubs. Did you use the Toyota hubs or the ones from Autozone? I've got a Duralast mr-s hub from autozone. Also what are you doing for the big washer on the back side to space out the wheel bearing?

I meant to ask in the previous post why the large washer is needed to space the hub from the knuckle?

I honestly havnt had them in a knuckle yet so I may have posted prematurely. Thinking about it, the only issue I can see is the back of the studs rubbing something on the knuckle, or the seal lip seating too far up the radius... probably the latter looking at it now.

These are china from rockauto

https://cimg6.ibsrv.net/gimg/www.mia...bfef085dc8.png

I believe Genesplicer implied that the big washer is needed to space the hub face OUT about 1mm so that the brake disc is still centered in the brake caliper. I have some question if that is 100% necessary. I also don't see why you need a washer in bore C, that appears to need to be machined down regardless so why not just machine to the depth you need and leave out the washer?

Bore C washer is probably for engineering purposes and / or so you don't get binding with the nut.

Bore C washer is probably for engineering purposes and / or so you don't get binding with the nut. Even though it is a flanged nut.

OK I need to double check some things, maybe I didn't carry a 1 lol. I measured that the wheel was pushed out 1mm as described above, adding a spacer would just push it out more. I might have my directions wrong and that may be "in" and not "out" lol.

The washer is needed because the splines poke through, the issue is that bore C is too deep, not that its not deep enough. You have to add material.

Ok, now I'm seeing what Gene did, I couldn't figure out why he machined the splines in the hub out, but you are right he added a piece. And yeah by eyeball it appears to me that if you don't have a spacer on the wheel bearing side the wheel will be moved in 1ish mm.

Im curious, to know how much that really matters with a factory caliper or even a wilwood as there is a little bit of wiggle room. In either case that can easily be added if necessary.

I agree. Especially for a single piston/stock caliper, which should self center anyway. If it became problematic you could also just shim the caliper bracket out 1mm. Probably easier to buy off the shelf hardened washers for those bolts vs machining a custom one for the bearing.

I think most of the time that 1mm offset wouldn't cause any issues with bolting it all together and rolling down the road. I'm less sure what happens when you are on the ragged edge on track and if that would have any effect on brake wear.

Also I think for the guys that are trying to run maximum wheel and tire width that small change in the offset could mean they have to get a 1mm wider wheel spacer.

Just looked at my numbers and yea I was thinking backwards :loser: the hubs in my possession are indeed 1mm in and not out.

I would agree on spacing the caliper rather than the hub, being cheaper/easier/better, except that the caliper bracket mounts to the outboard side of the upright mounting tabs and that would space the assembly out rather than in.

Assuming there is sufficient travel available in the caliper sliders and pad abutments(where the pads slide in the caliper bracket as they wear), I cant see this causing any issue.

The MR2 hubs without the hub spacer would push the caliper off the pins 1mm(caliper would move left in the pic away from the bracket), and bring the rotor 1mm closer to the bracket
http://www.miata.net/garage/ebrake/FigureD.jpg

Im thinking something like this

https://cimg3.ibsrv.net/gimg/www.mia...5cde8d2e01.png

Edit- fixed pic