charchri4

What I am running now is 15x9 +31 with 225/45/15 and they measure 23” tall with 8.5 of tread on the ground. It looks like this




I’d like to go to a decent street tire around 255 wide or so and the only thing that is out there are in 17s. The tires measure 25” tall x 10.2” wide at the tread compaired to 23T x 8.5W that is on the car now. Anyone know if I can stuff a 255/40/17 on a 17x9 +36 wheel in an NA?

cvx_20

Well, sure, that's the whole point of the 5-lug conversion

Although I think the offset was only 25 or so. And the weighed a LOT. The Bullets were 38 I think.

https://www.v8miata.net/members/cvx_...-gt500-476.jpg

I need to add all of my wheel pics to that blog I guess.

Mike

charchri4

Sweet! I remember that shot from your excellent wheel post. What size are the tires in the pic Mike?

cvx_20

235/45/17 on rear, 225/45/17 on front. Those wheels are 24mm offset, I was close.

Mike

mazdaspeedmiata

cvx can u post more pics of your car
close up fenders
direct front / back shot maybe

cvx_20

I'm going to be adding pics to the picture blog I set up. I just added all the wheels, a couple shots may be useful. The rear fenders were pulled and rolled, the fronts weren't. The front plastic bumper was trimmed for clearance early on, as was the Racing Beat bumper later.

I've sold the GT500 wheels, they were kind of pricey, and I didn't like the feel of the car with them. Could have been the tires, because the Bullitt wheels were borderline dangerous with the stock Mustang tires that were on them.

It seems to me that running 17" wheels is certainly do-able and is probably the wave of the future, but I prefer the look and feel of the 16's.

Mike

MiataV8 Conversion: Wheels

mazdaspeedmiata

im planning on running the 17x8 mustang gt rims
i pick them because they only weight 19 lbs and dirt cheap

charchri4

I'm thinking 275s on 17x9.5s falls into the go big or go home category....

mazdaspeedmiata

i see
u like to rub ....

charchri4

Nahh just messing around with a tire off a Firebird. Even with flares those 275s are way too tall. I ordered 17 x 9 3/4 wheels over the weekend and will see what I can get a way with for tires. In the front I think 235s would be easy, 245s with some surgery but I am hoping for 255s.

Amellrotts

How are people doing the 5 lug conversion?
I am starting to think about my tire options and want more than the 225 Rivals I am running on my Turbo Miata.
How negative will the extreme weight increase of my wheels/tires effect my handling? This car will have the torque, but will it offset the rolling weight?
I plan on a wide body so I can do any tire/wheel I want.....please give me your thoughts.....

charchri4

Thoughts you ask? I have searched under every rock and on every website for hours on end and THERE ARE NO GOOD TIRES FOR MIATAS! Period that’s it. I don’t care what size wheel or what offset you pick there are no good street tires available that are wide enough for a V8, and short enough to run on a Miata.

I'd walk to the moon for 295/30-15s in a 300 tread wear tire. Even 275s would be worth the trip. But you will never seen them becuase there are no factory production cars that use wide 15” tires to support wider sizes. The Corvette has used wide low profile tires for that last couple decades so the guys in Camaro and Mustang world have lots of great tires available to them. But our little Miatas have no such benefactor.

So like you most guys run 225/45-15s which is the biggest streetable size there is but still a very wimpy tire even for a turbo car. And all the tires in that size are expensive track orientated tires with only 7/32nds tread and a wear rating of 200. So good luck getting even 10,000 miles out of them. At the rate my Rivals are wearing I think 3 track days would completely consume a brand new set of them.

I can't answer your question about handeling with the Miata (yet) but I did go through this with my donor Camaro. I went from 17x9" 275/40 NT05s with 7/32s tread and 140 wear, to 18x10.5" 295/30 Ventus V12s with 10/32s tread and 280 tread wear. I got twice the miles out of the bigger tire which was the goal but no one was more suprised than me that grip for both track and autocross changed very little with the harder tire. The extra rubber on the ground made the difference and over all I saw no down side to adding probably 8 lbs of wheel weight to each corner.

I am in the process of going from 225-15s 200 tread wear to 255-17s 300 tread wear but it will be at least a month before I have mine back on the road to know how it will do.

cvx_20

I don't know how others do it, but here's one way:

MiataV8 Conversion: Five Lug Conversion

The downside is then you can't run 6UL's

Mike

Amellrotts

Jim,
Thanks for your reply, and the frustration in your words leaves me little hope of finding what I am looking for. I would love to find a 17x12 wheel that I can run 315/35 or 275/40 tires on. There are some decent street tires available in the bigger size for cars like the Camaro/Mustang. I am going to hack my body all to ---- so I won't have any issues with tire rub and thought the extra rubber would really help my cornering. I am very surprised to read that you couldn't feel much of a negative impact on your car with wheel weight variance as much as 8 pounds. Not questioning you, just surprise. Pleasantly actually. That gives me hope. Everything I have read on other miata forums suggest you must ad the lightest wheels possible or you will burn in hell. I have time to do more research, I just thought I would see what others had come up with. I found this thread while searching and saw where you planned to go to the larger wheel and was hoping to hear about your experience with that.

charchri4

Thanks Chris. Keep in mind that 8 lbs of wheel weight was on a 3600 lb Camaro that had 425 hp slinging them around. But still I think wheel weight is over blown most of the time. GRM did a test on that on an NC a few years ago and a couple of lbs per wheel made no difference in track times but it did affect feel especially on rough roads.

I agree completely with you 315s would be epic on a wide body Miata! The problem is cutting the fenders and quarters won't get you there. It takes a whole lot more surgery than that!

The deal is the absolute max tire size you can get away with is 24 5/8" tall. Any more than that and you hit the frame gusset on the fire wall on an NA and the upper fender support just rear of the head light on an NB. Both parts are not able to be cleared by rasing the car and both are major structural components of the chassis that short of building a tube frame and can not be modified very much and keep the integrity of the car. You have a bit more room in the back but anything over 25 1/2” tall hits the front of the wheel well at the rocker. The rocker would be no biggie to modify but my plan all along was to run the same size on all 4 corners so it was irrelevant.

So take that 24 1/2 max tire height over to tire rack and start hunting and you will soon be very discouraged. It doesn’t matter if you swap to 5 lugs or go to 16,17 or 18” wheels you are stuck with that height restriction and wide sub 24 1/2" street tires just don’t exist.

That being said there is one significant advantages to going to 17s IMO. We are losing 15” tires all the time as the auto industry continues to move to larger lower profile tires. So as long as BMWs, Minis and NCs have wide low profile 17” tires on them we will have a good supply of options for us too.

If you follow my blog you will see I am going through an extraordinary amount of effort just to go from 225s to 255s and no one in their right mind would do it. There is no question 30mm of width is not worth all the effort for performance or anything else. I just like tinkering on the shop...

Amellrotts

Jim,
Sorry I didn't see this sooner. The more I drive my turbo miata the more I think about the LS1 build on the horizon. My plan is for custom tubular control arms to widen my stance by at least five inches. I plan on "tubbing" the rear with custom metal quarters, but I had no idea I was going to run into trouble in the front. Truth is I have not really looked into this, I am only in the thinking process. Make no mistake though, I have a complete 2000 Camaro SS and pretty much everything I need to do the swap shy of an exhaust. So, Jim, what do you think I gain by going with wider front arms? Will it get me at least a 275/17?

charchri4

Interesting concept for sure. I'm not really seeing the advantage in longer control arms. For most wheels it only takes a small spacer to clear the sway bar at full lock and that much extra width I would think would really mess with the suspension geometry and effect the handling. Anyway I'll have to look again but I think 5 inches is enough to clear the rear frame support. Where it hits is directly behind the tire like where the clutch pedal is mounted so it takes quite a bit more width to clear the foot well area.

But there might be a better solution for you if larger tires. There is quite a few choices in 285/30-18 tires and they are just 24.7 tall. That is the max for sure but it will fit with just a little hammer work and flares. The reason I didn't go that size is IMO 17 already looks like too much wheel and the tires in that size are 50 bucks each more than 255/40-17s. And for me the whole point was tire options and $$s.

Gabriel

Hey Jim, did you ever end up getting your tires for the 17 x 9 3/4 wheels you bought? would love to see how it looks.. I'm a few months away from getting my project finished, but I'm really starting to wonder what wheel/tire combo to get... even 8 inch 15s really narrow the search... never-mind tire

charchri4

Yes I did Gabriel! 255/40/17s on 17x9.75 +25 wheel fit perfect on the car



Unless you want to drive it! It takes a bus load of surgury to make it work. I still have not driven the car with them but will in a couple weeks.

Gabriel

nice - I'm loving the ones you chose! let us know how it drives, and If it's not too much to ask, when take it for a spin, can you get a picture of the whole car with wheels on? you might have to let us know what you had to do to get them on, I'm starting to like the idea of 17s..

charchri4

LOL Gabriel you might not want to know! The whole disaster is spelled out on my blog but in a nutshell buying $250 fender flares was too easy so I've spent the 3 months and about 200 hours building a flare / wide body kit that will crack and fall off on the first bump I hit.












Now to be fair I would not have had to make them near this big and simple flares would have worked fine but I was going for bold and differnt. This is my inspiration:



And this of course... :-)

WolfGT

Jim, even if you don't stick with those wheels, please post up a set of good pics (side, front and at an angle) so we can see what the stance looks like. I will be coming up to this issue in a couple months. I have the advantage of the wide body, that may help me with choices.

charchri4

Be glad to Greg. I'm going to have her on the road in about 2 weeks to do a good shake down on everything and get the A/C finished up before paint. I'm running an autocross May 17th and I'll take lots of photos there. After that off to the paint booth!

BTW the only wheel tire combo that I like better than what I have is 295/30-18s and had it not been for the price of tires that is what I would be running now. Not as many 4x100 18" wheels to choose from but a few good ones.

charchri4

I rolled it out today and got some photos of it. I still have some work to do on the wheel arches but it's getting close. These are 17 x 9 3/4s +25 with 255/40-17s all around.

jreid1000

Hi Jim,
I believe you did the electric cutout. What muffler/s are you using. Thanks!
Jim Reid