I am curious if anyone out the has changed the wheels on a base model cobalt sedan. Specifically, I am interested in someone who had increased the size of the wheels. I have a 2005 base cobalt sedan. The car has had some problems that the dealer finally attributed to a defective axle which was replaced. With the factory 15 in wheels and tires, it seems that you can feel everything on the road, after replacing the factory wheels and tires with 16 in wheels and 225-50-16's the wheel shakes when going 50-60mph. It seems top smooth out above 60 or below 45. I thought that perhaps because of the wider tire that maybe there is an issue with the drivetrain that is being amplified due to the tire. I have discussed with the dealer but all they seem interested in is blaming the tires. (This was done before they even looked at the car. They associated it with the tires not being a good make, the wheels not being centered, the balance of the wheel, just about everything BUT the possability of it being the car). They basically dont want to touch it with the new wheels and tires on it. I am curious if anyone else may have this same setup on their cobalt with any issues? I bought the wheels and tires from Discount Tire Direct and am considering taking it to a local tire shop and have them rebalance the tires, although I really feel like there may be a problem that was there from the start. Anyone have any suggestions?
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If you still have the factory rims and rubber then re-install them and see if you get the same shimmy action at 50 mph. If you do, take it back to the dealer and tell them to investigate it or you will escalate the matter to GM Customer Relations.

 

i have 18's on my base coupe, perhaps your alignment is offaaaaaaaaaaaaaaaaaaa

 

I have a shimmy on my 2001 Odyseey at about 65 mph. It goes away when speeds reach over 70 mph and doesn't come on before 65 mph. I put 17" aftermarkets with wider rubber (225/55/17) and the whole friggin' dash shakes at the same speed. This is the second set of rubber on these rims, so the dealer can blow it up their ass when they tell me the tires need to be re-balanced. It's going in for a new tranny at 64,000 km (40,000 miles) so I am hoping it's been the tranny all along (I doubt it though). If the problem persists then I'm getting rid of the POS and I'm done with friggin' imports

 

lol 17's on a van?

 

Bro, AND on my Caravan. Check it out: http://www.cardomain.com/profile/dj4all

The gun metals that are in the first two pages are the ones on the Odyseey now.

 

do any of you feel like your steering is lose when going over bumps or potholes??? my steering wheel feels like it's not tight or something when i hit large bumps, i don't really know how to explain it?

 

What wheels did you put on and what size and brand tires? I had a lot of problems such as yours on the last car I had. I would take the car to Discount tires and let them road force balance them. I had that done on mine and it helped quite a bit.

 

That's odd.....don't really know what to tell ya. My wheel rocked back and forth really bad when my wheel studs broke, but trust me, you'd know if your wheel studs were broke. I had no problems with my 17"s, 18"s or 19"s in terms of shaking at high speeds, and even with the 35 profile tires, my ride isn't rough in the least.

 

I was looking for something else and found this, so I'll share a bit for the future.

Does your aftermarket wheels have a cover for the lug nuts? He same thing happened to my Civic 10 years ago. The reason is when the shop balances the tires, they balance it with the cap OFF. In my case, the cap was made out of metal. So it does have some weight. The cap would throw it off balance when it's on. When I took the cap off, my steering would not shake at around 60MPH.

I got another set of wheels later (without a center cap that covers the lug nuts) and it ran perfect for 100K+ miles.

 

I had the same problem, just went and got it re-alligned, had the same problem again, so I checked the tires and one of the wires on the inside of the tires was messed up, this can happen from hitting a curb with one of your tires, a tough bump, or anything hard you go over.

 

the tires are probly not blaanced they will tend to do that unbalanced

 

Did you use the hubcentic rings Discount Tire Direct gives you with the wheels? If not that could be the prob.

 

Just sending this out in case it will be helpful to anyone looking for rims for a Cobalt LS. I searched endlessly for 15 inch aluminum wheels a few months ago and learned some things. I did not upsize the wheel size fearing it would be out of spec. on the car and its still under warrantee. Most people do want to go up a size or two for better performance though. I looked at a lot of aftermarket stuff on line and in shops nearby too. I ended up getting aluminum replicas on line. I was skeptical, but they were 1/3 of the price of getting them from the dealer and so far they seem to be perfect. I did go up one size with new tires for the new rims, but the old tires would have fit. The aftermarket wheels required hub centric rings to adapt the aftermarket wheels to the hub and I wanted to avoid that with my limited experience with this stuff. The whole hub centric ring thing worried me with some of the stuff I read, but I guess a lot of people do it. The replicas went on with no problem and fit like original equipment. Hope it helps.

 

Here are my 18" Kazera rims with 215-40-18 khumo escara tires on my lt sedan. Has not been dropped yet though, gonna do that next when I get the money. Hope this is what you wanted to see. Tell the dealership to balance the wheels, and if they won't do it, take it somewhere else. If it continues after balancing, check the centering ring, you may need to replace it. At for ride smoothness, after getting lower profile tires, my ride is actually even smoother than the 60 series continental tires. The only problem is that I need to replace the brake rotors because they are warped.