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Old 03-16-2010, 07:33 AM   #1
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Largest Wheel for 986

I have searched the forum, but haven't been able to find a thread that answers my question.

What is the largest diameter wheel that will fit on the front of an '01 986 without contacting the strut/coil?

A 245/35ZR 19 on an 8J x 19H2 ET57 rim doesn't fit. Based on the tire specs, the diameter is 25.9".
Would a 235/35ZR 19 with a diameter of 25.5" work?
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Old 03-16-2010, 10:50 AM   #2
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Your question begs some questions.... I'm sure you mean largest diameter tire.

Assuming you've got 'stock' suspension when you say "hit the strut and coils", you're referring to the underside of the spring plates the coils sit on, right? It's hard to say for one thing because one side may squeeze in there and the other not. I've had 17" rims with just slightly too tall a tire (Victoracers)and it worked on the right, but not the left. I was able to 'mitigate' the rub by putting on 7mm spacers and with the angle of the strut to the hub/bearing carrier, it just cleared - luckily.

If it rubs underneath, you may be able to 'shave' the tires about 4/32 or 1/8" - they'll perform slightly better too.

25.5" might work.

good luck,

kj

Last edited by Boxster44; 03-16-2010 at 10:53 AM. Reason: add'l
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Old 03-16-2010, 11:32 AM   #3
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Quote:
Originally Posted by ancster
I have searched the forum, but haven't been able to find a thread that answers my question.

What is the largest diameter wheel that will fit on the front of an '01 986 without contacting the strut/coil?

A 245/35ZR 19 on an 8J x 19H2 ET57 rim doesn't fit. Based on the tire specs, the diameter is 25.9".
Would a 235/35ZR 19 with a diameter of 25.5" work?
I all due respect, your question runs helter shelter. In order to determine proper wheel fitment, one has to first create a baseline of information and calculate accordingly. For example, what are the sizes and offsets of your current wheels ? What kind of clearance do you currently have ? What type of suspension set-up does your vehicle currently have ? And are you likely to change it ? All of these concerns have to be factored in first. There is no exactitude in this regard. However, I can tell you from experience, depending upon the offset, most enthusiasts who upgrade their boxsters typically utilize the following widths: Front: 8 to 8.5 inches Rear: 9 to 10 inches . In addition, in order to achieve correct wheel diameter, wheel (diameter) and tire size (width and aspect ratio) ideally should comport with the same diameter as the factory specifications.
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Old 03-16-2010, 05:01 PM   #4
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Largest Wheel for 986

The wheels are 19" Sport Design. As mentioned in the initial post the issue I have is with the front wheel/tire. The specs on the wheel are 8J x 19H2 ET 57. The tire is a Bridgestone Potenza RE050 Pole Position - 245/35Z 19.

I have stock suspension on my '01S.

I'm trying to determine what is the largest tire diameter that will fit on the boxster without using spacers with the current suspension.

Thanks for your help.
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Old 03-16-2010, 06:51 PM   #5
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A 225/35/19 or a 255/30/19 will give you proper OD of 25". You will probably need a 5-7mm spacer for the 255s. The 255s really need a 9" wide wheel also.

You want a taller wheel up front so your Porsche will sit higher?? Rally car??
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Last edited by Topless; 03-16-2010 at 06:59 PM.
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Old 03-16-2010, 07:23 PM   #6
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Quote:
Originally Posted by ancster
The wheels are 19" Sport Design. As mentioned in the initial post the issue I have is with the front wheel/tire. The specs on the wheel are 8J x 19H2 ET 57. The tire is a Bridgestone Potenza RE050 Pole Position - 245/35Z 19.

I have stock suspension on my '01S.

I'm trying to determine what is the largest tire diameter that will fit on the boxster without using spacers with the current suspension.

Thanks for your help.
Again, I think that you are somewhat confused. When you say "tire diameter", are you referring to the profile of the side wall (aspect ratio) ? If, so, that would have little to do with "spacing". Perhaps, you mean to say tire width. In which case, you would have to calculate the difference between the width of the two tires, taking into account the offset of your current wheels, and see how it would effect your clearance. Personally, I don't think that its so much of an issue of clearance , as I do a potentially poor choice in tire size. In my opinion, running a tire as wide as a 245 up front on an 8 inch wheel doesn't seem optimal. That's quite a wide tire to be matching up with such a narrow wheel. I would have concerns about the tire remaining "seated" under demanding driving conditions. Moreover, from the standpoint of performance, I would think that a tire of that width on the front would cause an awful lot of "tracking". I know that some members of this forum run tires of that size up front. Perhaps, they can comment. However, most "tuners" and enthusiasts that I know typically run no more than a 235 up front and a 275 on the rear. Again, wheel offset can often dictate what the widest tire a person can use.

p.s. Just off the cuff, if you are currently running a 245/35 up front, it would seem to me that you would have to come down to a 30 profile in order to stay within an acceptable diameter.

Last edited by Johnny Danger; 03-16-2010 at 07:30 PM.
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Old 03-17-2010, 06:00 AM   #7
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To answer your questions:
1) When I'm referring to tire diameter, I mean the OD of the tire.
2) The tire size is larger than the recommended Porsche standard which would have 235/35 for this wheel. But, these were originally purchased for an '06 Cayman from a local Porsche dealership.

I'm taking the car to my local shop to see what options I have.

Thanks,
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Old 03-17-2010, 06:15 AM   #8
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It sure sounds like the fitment problem you're having is due width, not height. A .4" difference in diameter ( .2" radius ) is a 1.5% change, well within the allowed 3%.
As I mentioned in your other thread, Instead of buying expensive new tires, try a small spacer, 5-7mm ( with longer bolts ). That will either eliminate your rub, or cause the outside to rub, In which case you'll have to go to either a 235/35-19 ( factory 987 size ) or 225.
The 8" wheel is within the recommended range for a 245 tire.

Last edited by stephen wilson; 03-17-2010 at 06:22 AM.
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