I recently put on my winter set of tires and rims on my 09 ss/tc. The rims are 18's off of a impala I believe. I put the conti ExtremeContact DWS 225/45R18 on them. I also have a 6.5mm wheel spacer on them to fit over the brembos. When I do anywhere from 50mph - 65 i have a vibration in the steering wheel, but over 70, it quits. Does anyone know what the problem could be?

 

tires may need balanced better

 

Ya sounds like a balancing issue. Chances are they didn't do a road forced balance; my dealership tried to balance my 18s the easy way and they were so far out of whack I couldn't drive the car.

 

Okay, I dont think it matters but they arent Impala wheels, fwiw.

Did you remove the brake rotor retaining clips before installing your spacers/wheels?

Are the wheels properly torqued?

Properly balanced?

Spacers can make bad things happen.

 

What he said^

 

had the same issue with some 17"s i bought on this forum, the steering wheel vibes are from the front wheels and your seat vibes are from the rear wheels
my dealer was unable to balance them - they have one of those HunterForce extreme balance machines etc
I also took them to a tire/wheel place with a different machine and they also were unable to balance them

It would appear yours are also bent, you can have them repaired for ~$120/peice but you might as well buy new ones at that price...
I had the exact same issue, terrible vibrrations in steering wheel from ~55-70 and then from 70-90 it was fine, above 90 it came back. Bent wheels will damage your hubs eventually, i'd suggest taking them off the car

 

QFT ( my favorite word today) PLUS those "Impala" wheels may not be hub centric to your hubs (smaller) so you need to "star" tighten them OFF the car (no load) to make the wheel center on the hub via the wheel studs...ifyou dont big imbalance results even tho' the wheel tire assemblybalances fine off the car....

 

easiest way would be to get them roadforce balanced, when they wont balance you'll know they're bent

 

not to thread jack but if the place that is balancing them isn't roadforcing or checking for a bent rim when there is too much weight in one spot or won't balance properly then they are not doing their job. and the hunter machine is fine for balancing as long as it's calibrated every so often.

and qwikredline you should always tighten your lug nuts in a start pattern when it is off the car and then torque them in the same sequence to prevent warping the rim.

and shawn672 you do realize that roadforcing is matching the high and low spots of the rim and tire assembly to ensure a proper balance and doesn't always mean a bent rim. doing a runout check on the rim will tell you if its a bent rim or not.

 

actually my dealer's roadforce machine had a little arm that came down and sat up against the rim, as he spun it slowly you could see the wheel and arm making contact, and then not, and then making contact again as it spun around
it was visibly bent, it's likely fixable but I was quoted $120/rim to straighten out

 

they weren't roadforcing if your using the side arm off the lid, they were doing a runout check. next time you look at the balancer with the hood up look at the back you will see a big ass cylinder looking thing. that is what checks the roadforce of the wheel assembly.

 

/shrug i dont know how to balance wheels
they tried to force one, even tried weights and everything, wouldnt balance, checked with the little arm and showed me how it was all wobbly, put another wheel on the machine and checked it without trying to balance, same deal. it was all over the place

Dealer did a great job at trying, but I took them to another place that only does wheels and tires, with no luck there either. same results.. 3/4 are bent..

 

ya a bent rim is a bent rim, can't do nothing about that.

 

Tire out of balance