15" vs 17"

[Hal Copple]

I really actually like my 15inch Trigos's, with Goodyear GT II's on them. The tires are cheap, last a long time, just replaced the fronts which were still useable, at 40K miles, on the third set of rear tires, because i run my car hard. I dont' suppose the quality of the "ride" is important in these sorts of cars, but mine is very comfortable, even with a 1150 mile run without turning it off. I have heard the 17's are appreciably stiffer. I like the deep tread of the GT II's, and living in SC, drive in rain all the time. I am careful because of my engine torque, but i never have a problem with a feeling of hydroplaning. Besides, for me, one of my main enjoyments of my SPF is it's original look. I realize most folks would not notice the difference in tire/wheels, as they only vaguely recall the car anyway. But when i am sitting at a cafe, and some gent takes his wife over to my nearby car, and explains to her "these are very rare, historic cars, and we are not likely to ever see another one again" it makes my heart warm. The GT II's are speed rated for a sustained 118 mph, and are safe for brief runs well above that, because the car is so light, that the tires with proper pressure don't flex much, and don't get too hot. I have run as fast as 12.0 seconds in the quarter mile on them, too.

I have recently acquired another set of Trigo's upon which i have mounted 15inch Hoosier race tires, because my son wants to someday run the long course at VIR, where we will be on the south course in several weeks.

One consideration is your diff ratio, with the 17's you probably need to go down somewhat to a 3.55 or lower because of the much smaller rolling radius of the 17's compared to the 15's, i am running 3.73's which are perfect for my combination.

I have all the performance i can safely use for the street, as i save my hard running for my occasional race track driving. To me, it is largely a matter of original looks, tire cost, and ride.

I myself am a Vintage sort of guy, i guess.