17x10 & 17x11.5 ... Tire choices?

[Wild and Blue]

The more I look at this stuff the less I feel I should go ahead with out some opinions. I have all kind of charts but I am more interested in real world experience. Here it is....
I probably should have moved up to 18" wheels but I stuck with my original 17" and just went a half inch wider all the way around. My logic MAY be faulty but it was that I thought I could move to a wider than factory tire at some point but I could run the factory spec tires still on the car till they were not so new if I stayed w/ 17s and only went .5" wider on the wheels. The 275/40r17 and 315/35r17 combo has worked just fine but I really would like as wide as is feasible without worrying about rubbing. I am not crazy about getting taller sidewall height but that seems to be a must. Dumb as it seems, I also do not know if a variation between the upgraded front and rear heights from level ... AND compared to factory spec Front/Rear, is a big deal or not. Then there are the circumference differences where the change is not the same on each end. These are the # differences I have been able to find:
.................. 285/40r17 .................. 325/35r17 ,,,, Variation of:
Sidewall Difference: ( +4.0mm ) ......... ( +3.5mm ) ,,,,, .5mm
Overall Height Diff: { +8.0mm ) .........{ +7.0mm } ,,,,, 1.mm
Circumference Diff: [ + 25.13mm ] .....[ +22.0mm ] ,,,,, 3.13mm

OR
.................. 295/40r17 ................... 335/35r17 ,,,,,Variation of:
Sidewall Difference: ( +8.00mm) ....... ( +7.00mm) ,,,, 1.0mm
Overall Height Diff: { +16.0mm} ...... { +14.0mm} ,,,, 2.0mm
Circumference Diff: [ +50.27mm] ...... [ +43.98mm] ,,, 6.29mm

. I realize these are very small differences but they are not exactly on the same plane (completely level, as with the factory spec) and the front will not be raised the exact same amount as the rear. Maybe it is too small of an amount to worry about but I would rather expose my ignorance than screw up my car or buy a set of tires that won't work well. I hope I have explained in a way that it can be understood.
. Also, Does any one know who offers the 295/40r17 and/or the 325/30r17 tires ? Otherwise, with the 285/40r17 and 335/35r17 combination, the variation between front and rear will be even greater. I have found Manufacturers/Dealers for the other two but all of this is immaterial if I can't find a set in the right size.

[jonszr1]

did you send the wheels out to be widened? or did you buy aftermarket? the 285s arent a problem 295x40 i dont know of anyone making . 335s i believe there are only a couple of companies making. 18s might have been a better choice. to me the tires ( factory)are wide enough (but i am not a corner guy) the only thing i want to do is lower the car around the tires to improve the look.

[8upZR1]

I have yet to upgrade wheels & tires on my ZR1, but I have changed to and from staggered wheel sizes on mustangs and porsches and I personally have never felt a difference. I have gone from 17's all around to 18's up front 19's out back. Also from 18's up front 19's out back to 20's all around. All of these were relatively minor size differences as yours is. If you are truely worried, take a test drive and then srping for a set of adjustable coilovers. I imagine going from 18's all around to 15's up front, 24's out back would be noticeable. For the hassle I would just consider putting the stock size tires on the larger wheels. Because the rim has grown the footprint will be larger even with the same tires. Going from 315 to 335 on the same rim doesn't make that much of a difference.

[Aurora40]

I don't think you'll find any 325/30's or anything. The 335/35 is about as close as it gets. I believe several people have gone that route without problems.

To me your wheel choice sounds logical. There is a lot of selection in the stock sizes, more than there is in 18" sizes.

[Wild and Blue]

Thanks for the responses.
jonszr1; They are aftermarket. I do love the corners though. The LT5 and its reliability {with that kind of power} are foundational reasons behind my choice of a ZR1 but the 1g definitely pushed me over the edge. Those 270 degree on-ramps as well as the sweeping higher speed turns are a blast.
8upZR1; I appreciate the reassurance. I knew the difference was small and I had changed tire sizes on other cars but always equally front to rear and never on a car I cared as much for as this ZR1. I knew if I could ask the question, someone here had the experience. Coilovers are on the list of hoped for/planned upgrades.
Aurora40; Wow, are you ever right about the 325's. It seems like I have been to nearly every tire retailer on the internet and could not find that size even in race only tires, let alone street tires. I do feel a little less foolish, though, to find out I have more choices in the 17's than I originally thought.
It looks like the 285/40r17 and 335/35r17 combination is the way I will go. Now I just have to decide whether to run Goodyear D3's on the front and Michelins on the back or to just go with Michelins all the way around.

[Aurora40]

Originally Posted by Wild and Blue

It looks like the 285/40r17 and 335/35r17 combination is the way I will go. Now I just have to decide whether to run Goodyear D3's on the front and Michelins on the back or to just go with Michelins all the way around.

I personally wouldn't mix tires like that, if for no other reason than simply asthetics. I believe the Pirelli P Zero is also available in 285/40 and 335/35.

[Wild and Blue]

Originally Posted by Aurora40

I personally wouldn't mix tires like that, if for no other reason than simply asthetics. I believe the Pirelli P Zero is also available in 285/40 and 335/35.

Makes sense and probably the way I eventually would have decided to go, mostly the asthetics but also in case they "stuck" differently. I liked the looks of the Michelins better than the Pirellis but I am still checking out reviews so my choice is not set in stone as of yet.
Thanks