Wheels and tires...

[Sean]

On the old E3S, I had started a pretty informational thread on tires and wheels.

Well, I'm here once again.

Lets look at it this way to keep things easy, I'm going to list the wheel size, then ask what size tire would fit / look better. And, are the sidewall heights I have below, right? how much could I change them without messing with the speedometer too much?

16x7.5 wheel - 205-50-16 or 225-50-16?

16x7 Wheel - 205-50-16 or 225-50-16?

And, how about 15" rims?

15x7 - 205-55-15 or 225-55-15?


I'm going to guess overall that a 225 might look silly on a wheel only 7 in width.

I'm just trying to figure out what size to go with. Would a 225 rub the fenders without spacers?

The tires I'm lookin at are the Bridgestone Potenza RE750's - I just need to figure out what tire size I'd go with depending on the different size wheels I may get. If this thread is a little jumbled, let me know. :) I can try to order things so they're easier to follow.

[Erick]

Alex S. runs 225s on his 15x7 Kosei K1s...... I must admit they look sick! :twisted:

[Sean]

I'd have to agree, those do look pretty dang nice.

I was considering getting the K1's, but had set that idea aside. They seem to suit a track car more. I may or may not use my car to autocross. I would, but my dad's M3 is pretty fun to autocross in too.

Did he have to use spacers? Cause those sure to seem pretty far out there. And, would those rub too?

[alex]

Alex S. runs 225s on his 15x7 Kosei K1s...... I must admit they look sick! :twisted:

Back up here a bit. They are 16x8.5 and the tires are 245/45/16. A3SO3 Hoosiers. So you were wrong twice. Sorry :-) They don't look too bad, I agree here, thanks.

I'm using 1/4 spacers and the fenders were rolled also.

I've used 225/50/15 and 225/45/16 on stock car with no problems at all with Eibach Pro Kit. 225/45/16 is closer to stock in size.

I've also autocrossed 245/45/16 Kumho Victoracers with 16x7.5 rims on an eta car with stock suspension and 1/4 spacers with no rubbing. It might rub in the rear on newer body style as the fenders are a bit lower.

[Erick]

I read 225 somewhere.... sorry and wow... make way for my jaw to drop some more :shock: :P

[Sean]

LOL I thought those looked really wide for only 225's. 8)

So, I could get 225-45-16's without spacers and not have to worry about rolling any fenders?

I was thinking 225-50-16 was closer to stock, but you say 45 sidewall?

And, would 225's look alright on a 7 or 7.5 width wheel?

[alex]

make way for my jaw to drop some more :shock: :P

Here you go:

I'm considering using 285/30/18 for next season. They are only 0.1 inch taller than 245/45/16. Just a bit wider... The only a couple of drawbacks are cost of tires and cost of wheels. Did I mention the cost factor?

[alex]

LOL I thought those looked really wide for only 225's. 8)

So, I could get 225-45-16's without spacers and not have to worry about rolling any fenders?

I was thinking 225-50-16 was closer to stock, but you say 45 sidewall?

And, would 225's look alright on a 7 or 7.5 width wheel?

Correct, that's what I had on my car. What wheels are you using (size, offset)?

225s will look fine with either 7 or 7.5 wide wheel

You can use this for calculations:

http://www.miata.net/garage/tirecalc.html

[Sean]

Well, I was looking at the Borbet Type C's or Type T's.

I have my eyes open though, as those are getting harder to come by.

And, i thought that both wheels I was looking at had the right offset. And, what is that again? :D


Currently, I have the bottlecaps, which I plan on using as dedicated winter wheels. (which I already have tires for)

[Brew]

I've got 225/50-15's on my 15x7 Zenders. They fit perfectly.

If you really want to know every tire size combo that works, just calculate it out.

You take the tire width, 225mm, or 22.5cm, multiply it by the profile, 50% or .5, multiply that by two, for both sides, and add in the wheel size in cm. That will give you the overall height of the wheel/tire combo. The size I have is very, very close in overall height to the stock 195/65-14's. Within a few millimeters. 225/45-16 also works, and so does 205/55-15, there are a bunch of em'.
Then you gotta see what kind of offset your wheels have.
To run a 225, you need about 27mm of offset or less. 215's, about 32mm or less, 205's about 37mm or less, and so on and so forth.

[alex]

The offsets are:
( I got this from bmwe30.net few years ago)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
E-30 offsets

4x100mm, center hub is 57mm, wheel bore 57.1mm
6" rim width: 33mm offset = 4.7" backspace
6" rim width: 35mm offset = 4.6" backspace **
6½" rim width: 26mm offset = 4.7" backspace
6½" rim width: 30mm offset = 5.0" backspace **
7" rim width: 20mm offset = 4.7" backspace
7" rim width: 25mm offset = 4.9" backspace **
7½" rim width: 20mm offset = 4.9" backspace
** Factory sizes for an E30
Wheel diameter is irrelevant concerning offset.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Borbets probably have correct offsets but I'd definitely check before I commint to buying. There's usually a stamp on the inside that says something like "ET 25" where the number is the offset.

[Erick]

make way for my jaw to drop some more :shock: :P

Here you go:

I'm considering using 285/30/18 for next season. They are only 0.1 inch taller than 245/45/16. Just a bit wider... The only a couple of drawbacks are cost of tires and cost of wheels. Did I mention the cost factor?

Yes but you didnt mention the sickness factor in it 8) Anyways.... are you sure you really need that much rubber width?? :roll:

[Brew]

are you sure you really need that much rubber width??

Yeah, really dude. I saw that video of your car going up on two wheels. :shock: And you want more rubber??? You must be planning fender flares too, right?

[alex]

are you sure you really need that much rubber width??

Yeah, really dude. I saw that video of your car going up on two wheels. :shock: And you want more rubber??? You must be planning fender flares too, right?

No, I'm not sure I need more rubber. No, I'm not planning fender flares, I like how this looks:

http://www.e30.de/st/st3.htm

That partucular turn was very specific with just the right ingredients: high entry speed, decreasing radius, off camber. I know of another guy with E30 that went up on 2 in that turn at least twice.

[808BMW]

That should be your sig pic :P

285's deserve fender flares. Hell, you could even mold outriggers onto the flares :P