Ok I just purchased a new set of Z07 wheels the fronts are 18x9.5 and the backs are 18x11 now I need new tires what kind and what size should I put on these wheels. I may be driving the car 4500 miles a year. No racing or anything groofy just normal driving and oh yea I do not drive the the car in the rain.I live in Illinois so I don't have a lot of good months to drive the car . Thanks John

 

Hi John,

Greetings to you. And, I must congratulate you on a well chosen selection of wheel sizing. Upgrading to at least 18 inch wheels all around will certainly provide you enhanced esthetics. But, most importantly, improved performance, braking and handling. Furthermore, an 18X9.5 inch wheel for the front coupled to 18X11.0 inch wheels for the rear axle, is a fine example of an exceptionally balanced and race inspired "staggered stance". And, with the correct offset, the 11.0 inch wide rear wheels will fit in an "untubbed" C5.

Moreover, there are several tire manufacturers that offer appropriate tire sizes that you may choose from. However, IMHO, the manufacturer and model tire that will provide you perhaps the best tire size application in regards to available tire specs within that particular tire size range amongst most of the available tire manufacturers is Michelin.

For the 18X9.5 inch front wheels: The Michelin Pilot Sport PS2's in size 275/35-YR18, would be a proper fitment in tire width for an 9.5 inch wide front wheel width upgrade.

For the 18X11 inch rear wheels: The matching compliment and correct pair and application for the rear tires are the Michelin Pilot Sport PS2's in size 315/30-YR18. This specific rear tire size would be a proper fitment in tire width for the 11.0 inch wide rear wheel upgrade.

The reproduction Z07 wheels "should" already be in the correct offset based upon an o.e. offset application for an 18 inch diameter application. Consequently, you should not experience any troubling wheel fitment issues. Lastly, John, it sounds like you are on the right track. Therefore, I hope that this suggestion is helpful and insightful for you. And, please do post a picture for us all to drool over. Cheers.

Best Wishes and Keep On Waving,
Eden

 

Unless he upgraded his engine and got bigger brakes, the only possible benefit of going to a larger diameter wheel is potentially better handling from less sidewall deflection from a lower-aspect-ratio tire. There is always more mass in a larger diameter wheel, especially less expensive aftermarket ones.

All things being equal, performance and braking will decrease from larger wheels. If they are lighter than their 17" counterparts, which is highly unlikely, then there is potential for better performance and braking.
Not to hijack the thread, but wanted to help clarify.

You should get a 275/35R18 in the front. However, a 315/30R18 will be too short, and will **** off your traction control system. Get at least a 35-series tire in the rear. I suggest a 295/35R18, or if you don't mind the Toyo Proxes, a 305/35R18.

My rear track tires are 315/30R18 and I can't use traction control with them because the computer thinks they're spinning (because they're rotating faster, because they're shorter than spec).

 

I agree your handling, acceleration, and braking could be somewhat negatively effected by the heavier wheel. But if you were running runflats prior and you are switching to a high performance non runflat tire the lighter weight of the tire will probably offset the weight of the wheel. With softer and more rubber on the road you will probably see a little improvement, hard to say for sure. You will have less noise and a little better ride due to non runflat tires though.

Hey you did not get these to race anyway, right. And they are great looking wheels.

I also agree that the 315/30/18 and 275/35/18 will not give you a taller rear tire so that may not be the best choice. I ran 315/25/18 and 285/25/18 and had no AH/TC problems, although this size has been discontinued in the Pirelli Pzero Corsa competition tire I used. Most advise making sure your fronts and rears are the same overall diameter or the rear is taller to avoid AH/TC problems. Although there was a recent tire thread and several members stated they were running slightly taller tires in the front with no problems, I still would not take a chance on it.

Here is a tire calculator, just make sure your fronts are not taller than your rears in the overall diameter column.

http://discounttire.com/dtcs/infoTireMath.dosiscount Tire Co.

 

I Have These Same Rims I Went With The Kumho's 265-35-18 Up Front 295-35-18 In Rear No Problems

 

I would go with the Michelin Pilot Sport PS2's 315/30/18 and 265/35/18. You will keep the size offset that the computer likes too some degree. Many have said that as long as the rears are at least the same diameter (1 inch bigger is optimal) as the fronts you won't have any problems.

 

not true, wider tires means more traction (unless he gets tires that are worse than the runcraps), so you will be able to stop harder w/o locking up the brakes. The limiting factor on brake performance is (and always should be) the tires, as long as the brakes have enough power to lock up the tires (engage the ABS), they are doing all that they can do to stop you. The reason for big brake kits and heave duty track pads is not a shorter stopping distance, but a more consistant braking when the brakes get hot (repeated aggressive braking on the track)

back to the origional queation if you haven't already decided yet, you got a few choices. on the front you can use a 265 or 275 and on the back, you can go with 295, 305, or 315. The Z06 comes from the factory with a 265, 295 combo, so that's a safe bet (265/35-18 and 295/35-18 will work fine and is what I am running now (but my rear wheel is only 10.5") I am fighting a bit of understeer though, so my next set of front tires will be 275/35-18, it's not a problem at all on the street, just a little irritating at the track.

Also note, that the a lot of the T-1 Corvettes use a 275/315 combo and we know they are fast and well balanced, so that would get my vote, but you will probably have to tweek your suspension or alignment a little to avoid understeer if that is a concern to you.

 

Hello again,

With respect to John, and, to also "Lancer033" whom has posted a helpful response above: As Lancer and I have, in general, mentioned above, a wider contact patch (within a common street application) will, generally, improve braking, handling and performance above stock.

However, if one is opting to select tires for a dedicated track or race vehicle, then there are, indeed, a multitude of other issues to consider, such as, wheel width, the height of the sidewall aspect ratio that is more conducive to flex at launch during aggressive linear acceleration typical in 1/8 mile and quarter mile racers. And, in such a vehicle, it would also be prudent for one to also upgrade the braking and suspension systems, etc. Such a list of modifications can be long and suited to taste.

In John's original query, he did not state that he wished his vehicle to be a dedicated racer as one of his goals. Nor, did he mention that such an endeavor would even be considered as a monthly exercise. Also, John did not state that he wished to primarily select forged wheels for lighter unsprung weight, lower moments of inertia, nor, concerns with rotational mass. John instead purchased an exceptional wheel value that is streetable, and, meets his needs within an reasonable realm to upgrade from his current o.e. wheel and tire application.

Moreover, as Lancer mentioned above, the T-1 Corvettes use a "275/315 combo". And, the reason is that "they are fast and well balanced", which I also stated ("balanced") above. Furthermore, in general, most consumers do not experience issues with A/H, nor, T/C if they stay within the same overall diameter front to rear (as supported by "Shurite" above by his own experience), and/or, at least have the rears within an inch taller than the fronts. The Pirelli sizing combo that I suggested has an overall diameter that is quite close to eachother. And, in my personal experience, I have never had a problem with this tire and wheel combo because they both have nearly the same overall tire diameter.

In regards to tire width, a 275mm tire width is an proper application for a 9.5 inch wide wheel. The 265mm is just a little too short in width. And, on that same vein, a 295mm tire width is just a little too short for an 11.0 inch rear wheel width. However, despite such information, many consumers choose these and other certain sizes of their own accord because of lack of available, and/or, alternative sizing (this is key), lack of applicable model or brand knowledge, and, the constraints of one's own personal budget.

For, in fact, the final decision, and, chosen wheel and tire combo is the prerogative of the informed and interested consumer whom is prudent to take into serious consideration his or hers performance goals (if any), personal choice, daily driver issues, driver skills, one's pocket book, and, most importantly, what tire sizes actually exist to accomodate ones needs.

For further insight and information, you may access the following threads:

http://forums.corvetteforum.com/show...601&forum_id=1

http://forums.corvetteforum.com/show...3&forum_id=103

http://forums.corvetteforum.com/show...s&forum_id=103

As an interesting addition to our discussion of wheel and tire sizes.

In closing, John, I wish you the best. It is always exciting to explore how we may enhance various features of this already very extraordinary vehicle. And, to delve into the numerous options that are available, today. John, as an Corvette enthusiast, you are on the right track. And, I look forward to hearing from you. Please post a pic of your car for us to admire. Cheers.

Best Wishes,
Eden

 

I too just recently bought these in chrome. I went with BFG KDW2's in 265/295. The KDW's stick very well and are very good on the rain too, if need be. This combo really works well for me. BTW, mines a daily driver. HTH, Robert

 

get michilen pilot sports. they are the best!

 

Braking is a function of tire contact patch, you will have a larger patch with 18s in the front, but the tires and wheels do weigh more, we would hope that one would break even.

 

I'm starting to feel like the "lone ranger" when it comes to aftermarket tire sizes! Am I the only one who dreads the UGLY big gap between the fender and tire with those small side ratio tires? Unless you've got a SERIOUSLY lowered car, even a 315 in a 30 tire will give you only a 25.44" overall diameter with 18's. I think the rear should be at least 27" to look good in back, and 26" in front. The only way to close the gap with small side ratio tires is to go with 20" in back, and 19" in front - which I don't think looks real good either. The best approach I've seen (from an appearance point of view) is 255/40/18 and 295/35/19; which results in about a 26"/27" diameter combo which also enables the traction control to work properly.