I currently have on the front: 205/55 ZR16
Back: 225/50 ZR16

I was wondering if there is a better size for fit than what I currently have?

From the tiny image at left, it looks like your rear fenders (at least) might have a mild flare. Can you confirm? (Apologies if your build thread or equiv is well known.) This will have a lot to do with what might fit...

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I am running 225/50/16's up front & in back. I plan to go to 245/40/16's in back. Pretty sure they will fit but all depends on the tire company & the tire. That is on 16x8 fuchs on all 4 corners

I am running 16x8 Fuchs on mine with 245/45/16 Hoosiers. I think you will fit with a flair.

Dumb question, but I know they are 16", but how do I know if they are 8", as in is it stamped on the wheel somewhere? I'm guessing they are.

Yes. Looks like the fronts are 7, rear 8. Classic combo. I'm running the same width wheels and tires but adding a 1" spacer behind the front wheels to fill out the flare a bit.

Great looking car btw

I have fiberglass flares with 7" wheels front and 8" wheels on the rear.

Front: 225/50/16
Rear: 245/50/16

I could stand to push the wheels out a little with spacers to fill the flares.

Are the first 3 numbers related to the width of the tire?

If so, I could go to a wider tire for the front, or add a spacer in there somewhere?

I think it would look a bit better if it was closer to the edge of the flair.

The color black is going by the wayside to somewhere between silver, and closer to gray.

Spacing the front tires further out will fill the flares better, but will increase your steering effort.

225/50R16 = 24.9X8.86R16
Diameter = 24.9"
Width = 8.86"
Wheel = 16"
Sidewall = 4.43"
Circumference = 78.1"
Revs/Mile = 811.7

245/50R16 = 25.6X9.65R16
Diameter = 25.6"
Width = 9.65"
Wheel = 16"
Sidewall = 4.82"
Circumference = 80.5"
Revs/Mile = 786.8


The first three numbers in a typical size (225/45R17) are the tire's indicated section width in millimeters, measured from sidewall to sidewall.

If you are familiar with measurements in inches, the section width in millimeters can be converted into inches by dividing it by 25.4. For example:

225mm / 25.4 = 8.86"

The second pair of numbers (225/45R17) is the tire's aspect ratio or profile. This percentage represents the ratio of sidewall’s section height to the tire’s section width. The section height can be calculated by multiplying the section width by the aspect ratio percentage. The answer will be the height of one sidewall. For example:

225mm x 0.45 = 101.3mm
8.86" x 0.45 = 3.99"

The last number (225/45R17) is the diameter of the wheel in inches.

If you are familiar with measurements in the metric system, the wheel diameter can be converted into millimeters by multiplying it by 25.4. For example:

17" x 25.4 = 431.8mm

To calculate the overall diameter of a tire, the sidewall height must be multiplied by 2 (remembering that the tire diameter is made up of 2 sidewalls, the one above the wheel and the one below the wheel touching the ground) and add the diameter of the wheel.

101.3mm + 101.3mm + 431.8mm = 634.4mm
3.99" + 3.99" + 17" = 24.98"

Or just use this calculator: http://www.miata.net/garage/tirecalc.html

I wonder which would be better, a spacer or just a bit wider tire?

Like from my 205, to a 225, must gain about 5/8" wider tire for every 20?

So a 40 would be a taller tire?

I wonder how a low profile tire would look on it?

Spacer will give you more of a wheel flush with the body, but you have to be careful that it might be too far out and rub on turns.

What low profile tire size are you looking at?

Was asking about what size to use.

Where would wheel spacers be gotten at?

You can find spacers at the car junk yard off of 944's. Really depends on what size you need. Ebay tends to have used Porsche factory units.

Just have to figure out the depth, but something comparable to this:
http://www.ebay.com/itm/PORSCHE-M12-x1-5-3...c9f&vxp=mtr

It's hard to guess just looking at your pictures. A good start would be "how much clearance do you have with your current tires"?

Check the clearance around your tires, including at both left and right lock extremes. Don't forget to check the gap between the tire and shock absorbers.

Now you know how much room you have to grow. If the gaps are asymmetrical, then using a spacer to move the wheel out may give you a bit more.

Don't forget that tires move around; 1/2" clearance is about the minimum you want to avoid rubbing, and you may need more depending on sidewall height and driving style.

Be careful with this link. Porsche studs are 14mm, not 12mm. They probably
have a typo but if not you will be drilling. I've bought similar items on ebay from
different sellers who listed it correctly.

It's looking like it is going to be the spacer side of things. About a 1/2" clearance from where the tire is on the back side of the fender well, towards the outside. So probably keep the same size tire, but just get a spacer? Looks like I could grow about 1/2?

With the wheels straight ahead, I have about 1 1/2" from the edge of the tire, to the fender, and about 1 1/4" on the rear tire, to the edge of the fender. So I could maybe go wider on the rear tires, or spacer?

You can come almost right to the edge of the rear fender with a spacer/ wider tire.

The front I would give yourself at least an inch for steering clearance.

What thickness can the spacers be gotten in?

As the steering is cranked all one way, the edge of the tire runs at an angle over to the back of the fender, and so I wouldn't think much more over a 225 on the front, up from the 205 on there now, and could go 245, on the back, up from the current 225?

If I go spacers, my mechanic said I would need longer bolts/studs.

At some point the driver's side tire rubbed a bit on the inside, but not on the passenger side, so for some reason must have been a one hit wonder?

It appears for about every 20 points, is about 5/8" in width on the tire. Like from a 205 to a 225?

On the front, when doing a full tilt either direction, just eyeballing it, going another 1" might be forcing the issue.
I presume a wider tire would grow both directions, whereas a spacer just extends it out further?

On the front tire, edge to fender lip is about 1 7/8", and on the back is 1 1/4" to edge of lip. I assume I could go to a 245 on the back w/o any issues?

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Mine looks like if I go any wider than 1/2" on the front, when turning it will be close to rubbing on the back of the fender well?

Do you have any close up pics of yours?