I have a 21 C8, and when I hit about 60mph, there seems to be a slight shudder(subtle shaking) on the front end, I'm thinking this may be an alignment issue? I have 20" wheels on the front and 22" on the rear.

Anyone have something similar?

 

Likely your wheels need to be rebalanced by a shop with a high speed balancer.

-Mark

 

That’s what I was hoping, thanks

 

Depending on the miles, sometimes wheels/tires need to be rebalanced. It is possible that one of the stick on weights fell off, or maybe it was not done right the first time.
It is also possible that the tire has spun/moved on the rim. I had that happen on the C5 racecar, front and back tires.
The front were actually worse from braking.,, We would put a sharpie mark on the tire next to the valve stem. After a couple of track sessions, the mark would be 6" off.
On some wheels they move that far from heavy braking. That definately changes the balannce.

 

I am not knocking anyone’s decisions to alter their own cars but if you had come to me when I was building cars and I could not talk you out of doing this I would first make sure that the stock suspension set up did not need to be altered to accommodate the larger wheels and tires and then just to be certain I would run the car through a few handling test to see how much difference (if I had to guess it would be more than you would imagine) there was between stock and the current size. What most aftermarket sellers don’t tell you (back in my day we had to design and fabricate parts the proliferation of performance parts started around 25 years ago helped by the internet being available to most everyone) is that changing somethings can effect many things, as well as cause addition wear on parts that were designed to work on the car when it leaves the factory. I would also check if the wheels are bent I know someone that bought a very expensive Italian super car and after a year of ownership brought it over to me since he had been feeling a vibration in the steering wheel since he bought it. It was his first car of that caliber and it took me all of 10 seconds behind the wheel to realize the rims were bent, turns out 3 of the 4 were. Not sure what your reasoning was for changing the wheels ( and it is not my business ) but if you have not already done this I would check to see not only how the tires a wearing but if there appears to be wear on the suspension that is greater than your cars mileage should have.

 

I bought the car this way, so I didn't have anything to do with the setup... the problem has been solved with better tires and the road forced balancing..

 

Similar issue I had a few years ago. A weight fell off and was having issues. Took it to the tire shop, back to flawless in under an hour.