Here is the deal, I have found a set of tires brand new for a GREAT price. Just under 400 bucks for brand new BF Goodrich T/A KD. This is not the KDWs, the KDs are even better in dry traction, they just lack in the rain. They can drive fine in the rain but its not made to haul a$$ in the wet. That part is fine with me because in my magizine it shows how these tires out perform in dry traction best for max performance tires.

The problem, the set of tires are 17 inch. I used a special wheel fitment guide and it says that my wheel/tires will be off by 3.5 %. Will this mess up my computer? I know in today's new age cars you should keep the overall height of the tires/wheels the same as stock. Baisicly it said my speedo will be off ~ Speedo = 60mph I'm really going 57.3. Will be off about 3mph. What you all think of 17s instead of 18s.

+BUMP+
Update- I guess doing this will add more miles on my car because the tires will revolve quicker then the stock wheel/tire.

 

17's wont fit on the stock wheels on your ss/sc....you looking for new rims too?

 

lol, did you read what you wrote? Ohh n/m yea, trust me I know that 17 inch tires can't fit on stock 18 inch rims. I was just looking to get some feed back on getting 17 inch rims with those 17 inch tires I found. Was not sure if the computer would get messed up because the wheel is roatating faster then it would be with the 18 inch. Some cars are very touchy with that now adays.

 

Is the size of the tire negotiable?

If you went with 215/50/17, the difference would be 0.6% too fast (60 vs 59.6)
If you went with 225/45/17, the difference would be 2.5% too fast (60 vs 58.5)

Either way I don't think the difference would be a big deal.

 

No, the computer won't be messed up, just your speedo will be off. Are you really gonna buy new wheels just to use those tires?? And they will only last you about 8000 miles.

 

I really wish it was negotiable. I have one choice at that price. That price is unbeatable anywhere in the world. I just don't know if its worth getting 17s and throwing off my speedo just to get the best dry rated max performance tires cash can buy for less then 100 bucks a tire. After getting 17 inch rims its going to have to be lowered for sure. Do I want to drop that much cash and do it right the first time? End up buying 17s, the tires and a coil over kit. I was told springs will make your struts not last as long.

Exactly, its a great point. However traction in my Cobalt SS/SC is priceless after all...

 

Just get the KDW, better tire for real life. Twice the life, maybe 80% of the grip, ******* amazing in the rain, and availible in whatever size you want, for about $160.