So who has 17s on their SS? I want to downgrade to 17s, 1 because theyre slightly cheaper(already have a pair im considering to buy off a friend for dirt cheap), and 2, tires are cheaper. For anyone who has switched to 17s already, how do you like it? Is the ride any different, and did you lose any power?

 

why would they lose power from smaller rims? if anything they will gain acceleration from less weight, the ride will be smoother, because the tires on the 17's will provide more cushion

 

yeah smaller, lighter rims equal faster acceleration. It takes less force to turn the wheels freeing up some drivetrain loss, and your gear ratio is increased a little (depending on the tire size) but its not much of a difference

 

^^^^^^+1

 

your gears wont be as long and your top speed will also be hurt.

 

top speed in this car isnt that big of a deal

 

Only if your tire diameter is smaller. If you get smaller rims with the same diameter tire, you will shed weight ( reducing unsprung weight and rotating mass), and soften up your ride by adding more tire and air between the ground and your rim.

I would double check the bolt pattern on the rims. The SS and SS S/C have an odd bolt pattern.

 

The more tire diameter you add, the more your SS will roll during turns. There's a reason why GM put 18's on the Cobalt SC, they increase handling and traction. But if you feel like sacrificing your factory handling to save a bit of money, more power to you.

 

they put 18's on there to increase the traction? when's the last time you seen a f1, nascar, dragrace or salt flat car with low profile tires, more traction can be had with a smaller rim and better tires.. not necessarily slicks, just better tires

 

Exactly. You just have to find the tire with the right sidewall stiffness.

 

True, but how much are the tires you're talking about vs. the normal everyday tires he's going to put on there? The tires you're talking about aren't intended for dailing driving which is what we're talking about here. I just think his idea is flawed, he's not going to save money....

And yes, larger wheels do increase traction, which is why most RWD sports cars, super cars, and hyper cars have larger wheels in the back then they do in the front.

 

the bigger wheels have nothing to do with it. low profile tires have less traction than other tires, because they do not flex... at all and it is easeier to push something that gives a little to it's edge and not go over the edge. with low profile tires, once it slips it's gone and good luck trying to save it. so you could have 20"s with your p-zero low profile tires, and i gaurantee that same car with 15"s or 16"s and good tires would be able to outrun your times on a track.

and why do you think they put larger tires on the back? usually when you go to a larger rim IT IS WIDER. here's an example from the viper rt/10:

Front: 275/35ZR18
Rear: 345/30YR19

ok from this you see that the rear rim is 1" bigger, but it has a 5mm shorter sidewall and 70mm more treadwidth. so it has nothing to do with the rim size, it's 70mm wider. the other thing you have to remember is that tire manufactueres do not make every signle tire size that is possible. you won't have as many options finding a 345/30YR18 than you would with a 345/30YR19.

same thing with the tires on the cobalt ss.. go to tire rack and search for 215/45YR18 and then do a search for one size smaller sidewall and one size larger width: (common switch that is done) 225/40YR18 then you will see that there is 7 performance tires listed for our cars, and over 60 for the second set that would work on our cars.

traction has aboslutely nothing to do with rim diameter

 

ok, get your tire size correct. 275 is the width. 35 is the aspect ratio not the height of the sidewall in mm. To be correct the front tires have a height of 96.25 and the rear tires are 103.5 . So therefore the rear tires are bigger in both aspects width and height. If you go plus one or minus one remember to keep your overall tire diameter the same and you won't run into problems. Smaller wheels have more rubber and more flex vs. a bigger wheel. That in itself is a double edged sword when it comes to performance and handling. This can go on for pages...but my point is...get your facts about tire size correct. Knowledge is power and power is key to making decisions that will affect your life.

 

What I meant was that larger wheel usually is directly related to a larger tire. The more tire you have the more traction you have. Also the bigger the wheel the more torque it takes to make a single revolution – so inherently, larger wheels will slow your car down – which also means, more traction. I wouldn’t be surprised to hear that someone that dropped down to 17’s can scratch going into third if the tire diameter is smaller.

Low profile tires flex less in the turns, which is what the Cobalt SS was designed for, not a straight line. And I do understand that there are performance tires that will not do that, but who rides around daily on those tires? More importantly, if he’s going to try and save money on rim size, do you think he’s going to go out and buy a $300 tire? Probably not, so true or false - he’s going to end up with less traction and sloppy handling.

 

thanks for the correction.. i looked like this about 3 hours ago from a long night of drinking

 

well you said larger wheels, didn't mention anything about the tires.