Tires Options

[partwerks]

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?

[smj]

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...

[partwerks]

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?

[partwerks]

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?

[JRust]

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

[matthepcat]

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.

[partwerks]

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.

[mepstein]

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

[Kansas 914]

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.

[partwerks]

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.

[GeorgeRud]

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

[Kansas 914]

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.

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"

[matthepcat]

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

[partwerks]

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?

[partwerks]

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

[matthepcat]

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?

[partwerks]

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?

[matthepcat]

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.

[partwerks]

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

[mikesmith]

Was asking about what size to use.

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.