Coachmoe

Greetings!

I have a 2007 GT / CS and I am about to upgrade wheels and tires. Most likely going with a staggered package from AM. I would like to put
285/40-18's on the rear which is an upgrade from the 275/40-18's.

From the info on the AM site, this will not affect my speedo readings. Has anyone else used the same setup? Any pros or cons with the 285's?

Also, since I am changing from the stock tires, I would assume that an alignment would also be necessary. Is this correct?

Any help or input is greatly appreciated.

Jazzer The Cat

You will see no appreciable difference in speedo/ODO accuracy at all. I will say that running a 285 is gonna need at least a 9.5" wheel and not sure you have that on your ride. This is not a huge deal, but an oversized tire will give you lesser performance, for a few reasons. The wider may look better, but the extra width will just make the car a bit "looser" in the corners, generally speaking. With a 285 over the current 275's, this would not be much at all, but a 275 tends to be a bit this way as well, even though it is rated to fit on the wheel you have.

My recommendation is to stick with an OEM size tire, unless you are into a more corner-performance car. In such a case, I would steer you to a narrower tire, rather than a wider one.

What are your needs in a tire, in terms of grip? Lateral..... straight line.... or just general DD duties?

Jazzer

Coachmoe

Jazz,

The AM package has 9" front wheels, 10" rears.

As far as usage, my car is garaged from October 15, April 15. I drive it occasionally during the week and a little more on the weekends. I went to a few shows last summer and won a few awards. The bug has bitten and there's money in my pockets! LOL Therefore, I am setting out to basically being a cruise in / weekend show type of car. Since I have owned it ( April 2010 ) the car has not been in the rain.

This past season I put about 1,000 miles on it and I will probably put a little more next year.

Basically, looks first, then straight line I guess, although I don't envision a 58 year old school teacher doing a lot of street racing! LOL!

Thanks for your help!

Jazzer The Cat

You said that and the Kitty spaced out on you. I think I should be made to write "I will pay attention when the teacher is schooling me" like..... 5,000,000,000 times on the black-board or something

OK... a 285 is a fine fit for a 10" wheel and my general recommendation is to make sure the tires are worthy of the car in which they are to be installed. I don't see a link to your package, but Nitto NT555's are the usual suspects and are an OK tire. If they offer a set of Sumitomo HRZ I's or II's.... I would pass on them. They are just not a very good tire for the performance in which your car has to offer. The HRZ I's are a hard compound that offers little, in terms of grip in ANY direction and the HRZ II's, are focused more on water dispursion and you have no need for that.

If your car is a Summer-only ride, I have a hard time NOT recommending a higher-performance tire, as I know how much difference one can make. The difference comes in acceleration, deceleration via braking and cornering. Based on your described needs, the NT555's should work well for you and have a cool directional tread pattern as well.

OK... I feel better now having lived up to my montra on pimpin' good tires

Jazzer... doin' a little schoolin' of his own

Coachmoe

Jazzer,

The 285's are NOT part of the package I will get. I am going to upgrade to the 285's for a little extra $$$.

I did quite a bit of research concerning tire choice and the Nitto 555's were usually mentioned frequently. I feel pretty comfortable with those tires.

I think 305's are the next size after the 285's and some people had rubbing issues, so the 285's seem to be a safe choice.

Also, what do you think about the nitrogen fill? I am ordering the tires this week and they will sit in my garage inside their shipping boxes until April. Do you think that will be a problem or should I bring them inside?

Finally, will I need to get an alignment moving to wider wheels and tires in the front? I'm thinking yes. Thoughts???

Thanks again for the help and you don't have to write 500,000 times. Just be in my room for lunch detention TOMORROW... OR ELSE!

Jazzer The Cat

I will be more than happy to serve my sentence of punishment, if you are one of the following teachers:





I just can't decide between the two


OK... moving on now. I would LOVE to do a nitrogen fill on my tires, but my local shoppe doesn't offer it If I was to look around, I am sure I would find some, but no biggie. I have two sets of wheels/tires and swap them and let the air way down twice annually anyway. I know my race tires should be stored at like 20 PSI, so I just do the same for my Winter tires when storing them as well. I "think" tires need to be rated for N2, so just confirm it, if you would like to use it. You don't need to bring them inside, unless maybe you have sub-zero temps, but I am just not sure. Wont hurt to drop the pressure for storage, to be safe.

You don't need an alignment going wider tires, but if you want to improve cornering performance, you may look into some caster/camber plates to tinker a bit of each at some point.

Jazzer The Student

Torch_Vert

I'm running the staggered type setup being discussed with 285's in the back on 10" wide rims. VERY happy with it. Seems like a good performance match overall for the S197, and definitely has the look for car show/cruise duty as well.

Stoenr

that set up handled surprisingly well on the open track. i'm sure what jazzer mentioned would be more ideal, but I don't run open track events all that much.

Coachmoe

Gentlemen,

Last night I ordered new wheels and tires from AM. Going with the 285's / 255's and chrome Bullets.

Actually I ordered scads of goodies, valve covers, caliper covers and underhood goodies too. Unfortunately, the car is in storage and I'm afraid it's going to be a LOOOOONGGG winter... if you know what I mean!

UPS says next Tuesday. Can't wait; I cleared out space in the garage for all of the goodies to rest until spring.

Thanks to everyone who chimed in on this thread.

Jazzer The Cat

Be sure to hit up the customer rides "sticky" with pics when done

Jazzer