The Mazda 5.12 rear end is desirable and rare. I have two and they cost me dearly.
They are made by Jesse Prather every decade or so once demand reaches a certain threshold and apparently it is there. If you are in the market for one or want to speculate on the market, contact him to place your order.

https://jesseprathermotorsports.com/new/

Alan

 

If you don't know, jesse is a great dude.
no worries when dealing with him.

 

Thanks for the heads up. I just messaged Jesse indicating my interest.

 

Might jump on board with this. Is there a price estimate?

 

+1 I could use a spare

 

I heard from Jesse. He said he is making Miata units, not Rx8. But if 10+ of us want Rx8 He would consider it.
No pricing mentioned.

 

So, we're at 4 somewhat interested, depending upon price.

 

if the past cost is any measure I’d expect it to be around $1500 or so

 

Miata ones are $990

 

it’s just an estimate based on what it used to sell for, but maybe the source is different now

also the MX5 is a different differential; smaller, more popular fitment into other models

you could do a search on it if you wanted

 

I have purchased a new 5.12 diff gear set from "nodlaww" off ebay (https://www.ebay.com/usr/nodlaww).
He's in Brisbane, Australia, and has been selling rear gears for RX-7s and RX-8s for at least a year and has 100% positive feedback.
With tax, shipping, and handling, the exchange rate convert to less than $800 (take the Best Offer route)
He even has 5.375 and 5.8 gear sets!

Here is a current listing as an example: https://www.ebay.com/itm/13340607156...m=133406071562

 

^ i bought one of those and had been running in my track car for over a season now.

 

That's great to hear to provide some confidence in this vendor and approach.
My purchase has been shipped. I'll report on the transit time.

 

That's great Waldo is doing the 5.125 ratio. When I asked a few years ago he just had the 5.375 He's a very successful racer over here in Oz

 

Nice to know
I am considering 5.12 this year too

 

my friend who installed the diff and a heck of time trying to shim it. none of the factory available shims seem to be the right fit. had to make some custom shims.

 

Hello all,
I know this is quite the resurrection, but I have been looking into the 5.125 final gear as well, and also came across "nodlaww" on ebay.
I am unsure whether this guy is reputable, and reliable? He does not have a website, nor will he tell me who manufactures it (other than that it is made in China).
Could someone who have bought from him and used his product please let me know how did it go? Is the product good? Was it a direct bolt-on, or was there any processing required in order for this to fit?

Any help will be greatly appreciated!

Thank you!

 

I think I bought from same guy
He is using same pic

I had 5.3 from him
Noisy then stock , even with correct backlash
But no issue with Intense track use

https://www.ebay.com/itm/Mazda-RX8-C...154756-20017-0

 

Thanks a lot for the response! How long ago did you purchase from this guy? I was not sure if he was trustworthy & reliable because he couldn't provide me any information or websites, and so I was beginning to think this was a bit sketchy.

 

people on here buy from him as it’s the only new source, just search the name
.

 

Thank you Team! Is it true that this is a direct bolt-on part? Nodlaww told me it is a direct bolt-on. No processing required.
I thought I read somewhere on the forum that some was able to directly bolt it on, while someone else had to do some sort of processing or adjustment?

 

I bought a set from him a few months ago. Came in like 2 weeks. 10/10 would recommend.

Currently working on building the axle. So far the only thing I have to worry about is the pinon gear spacer.. but that's par for the course, and I am also putting a Cusco LSD in there so..

 

bought a 5.125 recently as a backup plan with the CD009 trans; using 2nd gear for drag launching with 1st reserved as a low speed pit/trailer gear, still reasonably low priced even with tax and shipping due to the exchange rate

it should allow 30 - 80 mph in 3rd without shifting for autox

bought some parts and tools directly from AU recently as well for the same reason



with the 5.3 and 5.8 gears the extreme tooth contact and resulting scrub is likely the noise issue. The 5.1 was already pushing it …


11p/41r = 3.727

11p/43r = 3.909

10p/41r = 4.100

10p/43r - 4.300

9p/40r = 4.444

9p/43r = 4.777

8p/41r = 5.125

8p/43r = 5.375

7p/41r = 5.857

.