Highest aspect ratio I can run?

[Jbauer]

i lowered the GT with the pro kit a few days ago, but the rear aren't as low as i would like them. It is my understanding that even if I go to 18s, i can actually have MORE wheel gap if the aspect ratio is smaller..so i figured, i can run my stock 17s with a higher aspect ratio, and the gap will be smaller, right?
Right now i've got 245 45 17, Is it possible to go to say.. 55 for the A.S?
Don't know much about wheels..so please forgive me if i come off like a dumbass

 

[Nightstick]

Best thing you can do is go here http://www.tirerack.com/tires/Spec....&vehicleSearch=false&fromCompare1=yes&place=6
and look at tire specs and see how much effect the ratio has on the OD of the tire. A wider tire of the same aspect ratio will be taller and lessen the fender gap.
I chose not to lower my car but wanted to do the same so I just went up to 255/45/17 on the stock rims. Its wider but its also 4/10s of a inch taller and made it look noticably better.

 

[Jbauer]

So what if i went to say..300/35/18.. would the gap look smaller or larger?

 

[isjoining]

gap would look smaller, but your speedometer would be 2.2% off.

 

[Jbauer]

But isn't 35% of 300 Smaller than 45 percent of 275? If aspect ratio affects the height of the tire; wouldnt i have MORE wheel gaps with the 18s?

 

[isjoining]

you never said anything about 275/45 tire size, so i was comparing it to 245/45/17. 300/35/18 will have a bigger overall diameter than 245/45/17 and therefore the gap would be smaller.

 

[Jbauer]

sory, typo- it IS A 245 45 17

 

[jprovence]

Are the springs brand new, if so, they have to take a few weeks to settle.

 

[Mustang5L5]

Give the springs time to settle.

If you start playing with wheel sizes, it also throws off the ABS system and will cause an error.

Stock tire diameter with 245/45/17 is 25.7". You need to stick close to this number.

Good tire calc to use
http://www.miata.net/garage/tirecalc.html