Fun with RX7 rims

[gavin]

Much thanks to Chunchoy14 for the notice of a local fellow who had a set to sell for 150$

I already had a set of 2nd gen PGT rims for use with 225/50/16 kumhos for autocross, but at 16x8@13-14lbs compared to 16x7@23-24lbs, this was a no-brainer.

BEHOLD! rims


PGT rims have the same offset as stock(42mm), the FDs have a 50mm offset. No problem there, just need an 8mm spacer and its all good......um...problem. Ive been having MAJOR rubbing at all 4 corners. Overwide tires, massive camber....and now I want even wider rims(??!!). I need bigger spacers!

luckily there is a provision in the class I race that allows using spacers to correct for rims +-5mm from stock. lets see, 8mm plus 5mm, thats 13mm. 1/2" is about 12.5mm. That works.


For anyone who guessed that I would need longer wheel studs, give yourself a pat on the back. The lug nuts wont even touch the wheel studs this spaced out. I need longer wheel studs!

the stock studs are 42mm/40mm (f/r). I needed something 10-12mm longer with the same thread pitch (12x1.5) and same knurl diameter (@13.06mm). A trip to the local shop netted these. The closest to the measurements that I needed


A meeting with Rickyracer at the ALMS/Speedvision races netted some cool info about this subject. Aparently ARP has wheel studs for Camaro/Firebird/Corvettes that are 12x1.5 pitch at 2.5" long. Ill be getting those another time. (BTW Rickyracers car is an amazing machine. The fit, finish and workmanship is incredible).

As it was, I needed new rear rotors and new front/ rear wheel axle bearings, so I got the studs pressed in at the same time.


One final adjustment. The rear tires were just a bit too close to the fender lips soooooo.


There. Now wasnt that the easiest thing to do?



Gavin

[iggypop]

nice work ...been there , than that (check my sig )

i found that aftermarket studs are [shizzle] . i snapped 2 off and after that i said hell with this [shizzle] ,so be carefull ..

you need to PM AdamTurbo to make some hubsentric wheel spacers .

[Urethane]

It may be the torque created by the leverage of the big ass spacer that snapped the studs. Unless you found ones of higher grade that cured the problem???

[GT40man]

gavin needs a body kit. i go so spoiled with the one on mine. your car looks so plain, so 80's.

[2Rusty]

I already had a set of 2nd gen PGT rims for use with 225/50/16 kumhos for autocross, but at 16x8@13-14lbs compared to 16x7@23-24lbs, this was a no-brainer.

RX rims look good. At that weight it's hard to believe you even considered the 2g PGT wheels. With the addition of increased 225 tire weight those would have to kill your track performance enough to make the stock 15's the better deal.

PGT rims have the same offset as stock(42mm), the FDs have a 50mm offset. No problem there, just need an 8mm spacer and its all good......um...problem. Ive been having MAJOR rubbing at all 4 corners. Overwide tires, massive camber....and now I want even wider rims(??!!). I need bigger spacers!.

Those PGT wheels are only 40mm, so not quite the same as stock. But let's not concern ourselves with that.

luckily there is a provision in the class I race that allows using spacers to correct for rims +-5mm from stock. lets see, 8mm plus 5mm, thats 13mm. 1/2" is about 12.5mm. That works.

I'm confused, wouldn't the math work out like this: 8mm minus 5mm spacer = 3mm or a total running offset of 45mm? Definitely within the 5mm provision though.

Car keeps getting better. Keep it up. Could you possibly snap a picture of your rearend (not yours, the car's) close to the ground? I would like to see how wide those 8" wheels look.

[gavin]

Iggy...Of course I remember your site Ive gone through it on many an occasion(nice FE btw, harness and ecu, nice.) Why DID you sell your FDs?
And yes. I am keeping an eye on the studs. I did take care to find ones that had a larger unthreaded section so there would be less of a chance for snapping at the threads( theyve survived one autocross already). I am definetly getting ARP studs, much stronger.

GT40man.... HEY! I resemble that remark . I prefer to say "tastefully early 90s "

2Rusty.... I got the PGT rims years ago for 100$ and when I decided to go racing the rules for street touring said 7.5" rims max. So I kinda just ran with them. They were strong(bombproof almost), fit the tires I wanted, fit the car with minimal hassles, and..I had them. This year though, 8"rims are allowed in street touring "X", so thats why I switched. Whoo hoo.

You know, now that Ive been looking around I see 2 listings for the PGT rims. 40 and 42mm. Maybe thats where I erred. But as you said, not that much of a difference.

And right again(kinda) about the math. I should have said that I was subtracting positive offset. Start at 50mm minus 12.5mm(the 1/2" spacer) and voila 37.5mm offset. Still within the 37mm allowance given from the stock offset(42mm minus 5mm).

Gavin

[iggypop]

mine were 641-2169 wheels bolts with unthreaded section just 'lil bit longer than yours . i tried 5/16 (8 mm)spacer , but rims still would not fit . then i glued 2 togheter for rears .. i ran 205-55-16's no spacers in fronts , though . it rubbed all the time and when bolts started breakin , then I said heck with this ...

yep , thanks on Fe ..Let s just hope that ECU works ....
hey , i m geting a donor for my FE. its same color as your's ... only thing though , its kitted ..

[GT40man]

yes iggy is getting my old 6er.

[Jon]

Look for the thread that has like 7 billion replys and is titled "Gavins All Out Suspension Thread"

[gavin]

2Rusty... Pics.



Couldnt get the flash to work as well on the wider shot.

Gavin

[Jah1mon]

That should have been the set of wheels from the factory for a MX6. I wish 3rd gen RX7 wheels were more plentiful. Gavin are you still using Kumho's on the new wheels? and did you notice a difference in drivablity over the weight difference in the rims?

[Urethane]

looks nice, bet that thing handles like a dream. Where did you get that rear lateral link tie bar? And did you have to get a longer pivot bolt to get it to fit? Or is it stock on the 91's?

[2Rusty]

Wow, looking very solid there. I love the way wider tires help box off the rearend on the 1st gen. Urethane, that's a stock tie bar but gavin has poly bushings on it, of course.

[gavin]

Jah1mon.... The Kumhos were moved from the PGT rims to the RX7 rims. Ive run them once so far (amazingly everything held together ). The conditions that Im used to running is on the clean, flat, concrete surface at Marina airport. This time however I was running on a parking lot surface( Asphalt, bumpy, semi gravelly) so it was a bit difficult to say how much difference there was.
The car did seem to be a bit better off with the bumpier surface, more stable and less prone to be knocked off line. But again, with two very different surfaces its really hard to say(Im sure it doesnt HURT things to be less weight though).

Keep a look out for rims. 3rd gen RX7 owners tend to upgrade to better rims so the stockers are usually up for grabs. 2nd gen PGT rims are heavier but also available for cheap.

Urethane.... the tie bar will fit the 88-89s with no problem. The bolts are long enough already. It should be a cheap item from the dealer too considering that the rear strut tower bar is @ 65-75$.

2Rusty.... Funny you should mention the tires. This past sun at the local BAPOC meet one of the guys in a 2nd gen mentioned how wide the tires seemed. Its the same profile as a stock 2nd gen PGT I mentioned. He countered with, "Ive got 235s and those are wider than mine". We decided to check and he was right. The width was wider(probably due to the 8"rims) and the actual amount of tire touching the ground was wider also. I did notice that his Dunlops had more "overhang" (the remainder of the tread pattern that doesnt touch the ground, thats how Id describe it) compared to the lower overhang of the Kumhos.

I guess depending on how the tire carcass is designed and the rim width used you can get a "narrower" tire to have more contact area than a "wider" one . Funny stuff.

Gavin

[91maz626lx]

does anyone know if the new rx8 wheels will fit or even the 5 lug mazdaspeed prodege wheels. i work at mazda and i can get them cheap, and i know what your thinking why can't you do this yourself, well the rx8 is not listed on any manuals yet, and even if they did i don't think they have the lug size so plz help