Specific Wheel/Tire fitment question

[sjwelna]

Hey guys, I'm finally in the market for some new rims/tires. I have decided to go with the 5Zigen FN01R-C's in gloss black with a polished lip, 17x8" rim with a +35mm offset. I also have chosen to put on some Goodyear Eagle F1 GR-D3 rubber on the rims in a 245 wide tire. My question about fitment on my 2g awd is as follows: Will I be able to fit this rim/tire combo on in a 245/45-17 with the given +35mm offset? If not, would the 245/40-17 size tire be a better fit? If I can fit the 245/45 on without rubbing the knuckle, I will, as it will give me a better ride than with the 40-series tire and is closer to the oem tire size. What do you guys think? I'm trying to be as specific as possible, but if there is anything else that you need to know, just let me know. The car is on the stock suspension for now, will be putting on Tein Flex coilovers in the future, and I am willing to roll the fenders if needed.

Thanks,
Steve

 

[wret]

You will be well away from the knuckle with either of the sizes you mentioned. Your problem will be on the other side of the wheel: the fender. A 245 tire on a +35mm offset wheel will protrude about 1/4-1/2 inch. With high enough and stiff enough suspension, you should be okay. The clearance issue will be lessened with the 245/40/17's because of the smaller diameter. Also consider 235/45/17's.

 

[sjwelna]

You will be well away from the knuckle with either of the sizes you mentioned. Your problem will be on the other side of the wheel: the fender. A 245 tire on a +35mm offset wheel will protrude about 1/4-1/2 inch. With high enough and stiff enough suspension, you should be okay. The clearance issue will be lessened with the 245/40/17's because of the smaller diameter. Also consider 235/45/17's.

From what I have seen on tirerack.com the difference between the 235/45 and the 245/40 in terms of diameter is pretty minimal (.3" difference total, the 245 being 25.7" in diameter and the 235/45 being 25.4") With this in mind, do you think I would have problems with these tires rubbing in the 245/45 size on stock suspension? I plan on rolling the fenders up a bit to try to make as much room as possible. If this were your car, which way would you go? Tein recommends a distance from the center of the rim to the top edge of the fender of 13.5", which means that with the 245/45 tires, I would potentially have a distance from the tire to the fender of .65" with the 245/45, a gap of .8" with the 235/45. According to tirerack, they don't offer the Eagle F1 gs-d3's in a 245/40, but I am trying to find the diameter of this size (if available) to calculate the potential difference in the gap from tire-fender for your information.

Thoughts?

-Steve

EDIT: I found the info about the 245/40 diameter tire on goodyear's website, which is shows a 628mm diameter, which is about 24.7", which leaves in theory a 1.15" gap between tire-fender. Obviously this is a fairly big difference compared to the other two, but will the ride quality be significantly degraded going from a 45 series tire to a 40 series?

 

[wret]

Don’t go blind researching tire diameter specs. They all conform to standard calculated sizes. http://www.miata.net/garage/tirecalc.html Width is a different story.

You are getting ready to lower your car onto stiffer springs and dampers, and low profile tires and you are concerned about ride quality? The signal to noise ration will be such that it will be difficult to discern the difference in ride quality between the 40 series and 45 series tires.

Don’t get hung up on Tein’s wheel gap recommendations. They are adjustable after all. Did you read the part where they say “FOR OFFROAD USE ONLY?”

Thoughts? Same as before. 245 width tires on +35mm offset wheels will protrude and will require some careful suspension management to keep them out of the fenders.