1st Gen SA/FB answer to all of your wheel questions! Hardcore TECH.

[P71]

After doing this >>> for the last month I have solved the wheel problem for us poor SA/FB guys with 4x110 that don't like Konig's/Rota's/Panasport's.

First, some stock dimensions of the "+" wheel:

Diameter: 13"
Width: 5.5"
Bolt Pattern: 4x110mm
Backspacing: 120mm/4.7"
Offset: 38mm/1.5" POSITIVE
Bore Diameter: 2.375" (roughly)
Lug bores: 3/4" (roughly)

OK, so other then finally having a real number for the offset/backspacing, what good is that info? Easy. Nobody makes a 4x110 wheel I like, and 4x114.3mm/4x4.5" is extremely popular. That's why GSL-SE stuff goes for massive $$$. What about those of us either A: on a budget, B: where GSL-SE stuff has dried up, C: can't change the stock brakes due to race class rules, or D: like me, in all of the above?

The answer is adapters. Yes, adapters. The stock flange on the SA/FB brakes is only 3/8" thick. A 3/8" thick adapter will allow double the lug-bolt strength, have a 4x114.3mm STUDDED pattern, and will allow a 15"x8" wheel with a +15 offset to bolt on and be in the STOCK location. As any of you who are into other cars know, that size/bolt pattern wheel is about the most common on earth right now.

So here's what you need:

Diameter: 15"
Width: 8"
Bolt Pattern: 4x114.3mm
Backspacing: 129mm/5.1"
Offset: 15mm/0.6" POSITIVE


Why a 15x8? Well, the stock tire is a 185/70/13, not exactly easy to find. A 205/50/15 (again, about as common as dirt thanks to the Civic and the Miata) is the same rolling diameter and designed for a 15x8 no problem. So you don't have to worry about fender rubbing, strut rub, or even changing out your spedometer gear.

OK, so you need a 4x110 lug to 4x114.3 stud adapter in 3/8" thick, where to buy it? Well, I'm having a set custom made. Now that he'll have the CNC program setup he can make them whenever I want. A group buy could easily be arranged. I'm sure there's a bazillion outfits out there who can also one-off you a set.

OK, but what if I'm not comfortable with only a 3/8" thick adapter? Easy, use a common 1/2" thick one. The fender-to-wheel clearance can allow the extra 1/8" with no problems whatsoever.

Any questions?

[P71]

While the 15x8" is 2.5" wider of a wheel, the whole "package" is only 20mm wider, or about 3/4". The 185's "balloon" off of the stock wheels while the 205's and the 8" wheels are the same width.

Look at it like this, the tread width and section width of the tire are the only things to worry about as that's what gets close to the fender lip. The stock 185 tire has a 185mm tread width (give or take, each tire brand/model will be different) which is 7.3". The 205 tire has a tread width of 205mm which is 8". So even with making the backspacing/offset equal, the increase in overall width is only .7" or about 18mm. That's less then 2cm and less then 1". There's a good 1.5" in between where the tire would be and my fender lip. The only real difference is where the wheel itself is in relation to the body, and with most +15 15x8 wheels you will end up with a deep lip so it's only the actual "rim" that will be out the additional amount, and there's plenty of room to grow in that area from the "+" wheel!

I attached some pictures

[Nutsid]

Absolutely fantastic writeup. There needs to be a sticky thread at the top with links to posts like this one. An FAQ sticky, for example. This explains things beautifully.

[TheDriver216]

as soon as you get a price for a GB im down

[TypeSL_T]

Originally Posted by TheDriver216

as soon as you get a price for a GB im down

+1

James

[ROTOSPEED]

+2

i need a set of these

[djjjr42]

Originally Posted by P71

The answer is adapters. Yes, adapters. The stock flange on the SA/FB brakes is only 3/8" thick. A 3/8" thick adapter will allow double the lug-bolt strength, have a 4x114.3mm STUDDED pattern, and will allow a 15"x8" wheel with a +15 offset to bolt on and be in the STOCK location.

Can you clarify what you mean by the "stock location"? If the wheel/tire is wider then it either has to stick out from the car more or inside the fender more, right? The reason I ask is because IIRC some SA owners had issues with the tires on the Rewind's rubbing the strut tower.

There is something else worth noting here. I'm not trying to rain on anyone's parade, but I think a lot of people fail to take into account when upgrading their wheels that the stock brakes are designed to work with stock wheels. Having that much more unsprung weight and rubber on the road changes the handling characteristics (which is good in some cases, like for the snap oversteer), but that also increases the load while braking on the rotors and/or drums, to well beyond the limits of what the stockers are designed for. Larger brake rotors and pads would be ideal, but I understand for racing class rules that isn't an option. Safety should be of utmost concern at all times, and a lot of us (including me) more often think about going faster, making the car look better, etc. instead. At the very least you will burn up your pads much faster. But a busted rotor could get really ugly. Also the extra weight and friction from the wider tires translates into a loss of drivetrain efficiency. It takes more power to turn the larger, heavier wheels across a larger surface area. You will not be able to get off the line as fast as you can with the stockers.

A real world example of the safety issue happened to me a few months ago. I have the 15x7 Rewinds on my GS. On the highway one night I had to lock up to avoid rear ending an SUV that had to lock up to avoid a deer. I didn't know it at the time, but when that happened I blew out the rear wheel cylinder. Brake fluid leaked everywhere in the drum, and a week later I was driving and the fluid caused the lug bolts to work out, and all 4 came out at highway speed. Luckily the drum just dropped down inside the wheel and it stayed under me. I wasn't hurt, and the damage was minimal. But if it had been the front it would have been a much different story with a nastier ending I'm sure!

[warwickben]

bump

[P71]

I'm still working on it guys. Freaking adapter places want more for the adapters then the wheels!!

I am finding alternative solutions, I'll have links for you in a few days.

By "stock location" I mean stock location in relation to the strut/inside/total backspacing. Any additional width will stick out into the fender (where let's face it the stock wheels aren't exactly filling it up).

[warwickben]

i had a link hat would make custom spacers for around 100$.ill see if i saved it. all so ask billy he mite be down for making them. heck ill go post in his section.

also when you get the spacers made you need the right size hole in the center. a problem a few people found out the hard way with the rewinds is you need a insert ring or the lugs can work them selfs free. dont bash me for this but i wish i could get adapters to convert it to 5 lug so i could try to get built type rims for my sa. i know i know there ment for mustangs but i do own a rs turbo capri and love those rims.

[djjjr42]

From Mariah's website (http://www.mariahmotorsports.com/):
"We are now in the development of wheel spacers to allow 1st gen RX-7's, with the 4x110mm bolt patterns, to fit FWD application wheels and open a whole new world of custom wheels to the 1st gen RX-7."

[Rogue_Wulff]

The +15mm offset works great on FB's, and *should* eliminate the issue with the SA/Rewind combo. The Rewinds have a +20mm offset, which moves the edge of the tire 5mm closer to the spring.
I have 15x7 +15mm offset 4x110 wheels, with 205/50-15 tires. The car has a very old set of ST springs, which have lost there integrity, so the car sits VERY low. By low, I mean ~1 to 1.5" off the bumpstops, without me in it. That's after I cut 1.25" off the rear bumpstops.
I have very minor rubbing on the rear fender lips, after rolling, since I cut the bumpstops.
I have acquired Grond Control coilovers with Eibach springs, and matching rear Eibach racing springs, which should raise the car back up. Once those are installed, I plan to step up to a 225/45-15, on those same wheels. The 225/45-15 is 20mm wider than a 205/50-15, but within 3-4mm diameter, so the speedo will remain dead on.

However, if there was an inexpensive source for adapters, I might consider a set, for more wheel options. I do need another set of wheels, for race rubber......

[P71]

OK, here's the skinny. There's a very easy and cheap way to convert without having super-expensive custom adapters machined.

First, you'll need "wobble bolts":

http://www.ezaccessory.com/PCD_Varia..._p/98-0048.htm

This will allow you to do 2 things. One, install correct offset 4x108/4x4.25 wheels directly to the SA/FB brakes. And two, will allow you to use this:

http://www.ezaccessory.com/Wheel_Ada.../4425-4425.htm

It's just a 4x4.25 to 4x4.25 adapter BUT it has the proper width to allow you to run FWD/modern offset 4x108/4x4.25 wheels (using the wobble BOLTS to bolt the adapters to the brakes and regular tapered lug NUTS on the built-in studs, opening a HUGE amount of aftermarket wheels!).

These same guys also offer a 4x4.25 to 5x114.3 adapter and a 4x110 spacer. They will also special make a 4x110 to just about anything adapter (but realize that that will be more expensive.)

So have at it!

[warwickben]

thanks for the info have you tried this out yet?

[P71]

Not the adapters, though I know those work.

The wobble bolts work GREAT for 4x4.25 wheels. A set of of early fox-chassis 14"s bolted right on and looked great. Not enough offset for me, but the bolts worked as advertised, which opens up a whole new realm of wheels.