Get into www.tirerack.com and compare original tire specs (sticker on driver's door) with possible aftermarket choices, especialy outside tire diameter. The entire powertrain and speedo system is calibrated for the original OD so you want to stay within +/- 0.5". Yes, the loss of a bit of airspace beween the wheel and road will result in a harsher ride. Smaller OD, tire rolls faster, fast speedo; Larger OD, tire rolls slower, slow speedo - among other calibration mismatches.

 

Get into www.tirerack.com and compare original tire specs..........

Will do, thanks man!

 

As far as those wheels, I’m sure they’ll fit. It’s nearly impossible to type in what kind of car you have and somehow be sold wheels that don’t fit the car. The computer systems won’t allow it.

Another option that could satisfy your visual desires while maintaining if not improving the current ride of the vehicle would be upgrading to Vogue tyres. The whitewall & yellow stripe tyres offer the visual aesthetic of having a larger wheel while maintaining everything OEM. [they also offer red stripe]

 

Thanks for the insight! I too thought about leaving the factory wheels as you have done and get the vogues, about $400 a tire. May be worth it!

 

The 20s ride Harsh. 22s? Why bother with a Tire at all?

 

That’s ironic you should say that. I had a caddy in the 90’s, and bought this vehicle out of state, no test drive. Merely due to the design, I love this vehicle, but, I was very, very surprised at the “rigid” ride this had compared to an “old” caddy per say. I do not find the ride to be smooth at all on the factory 20’s.

 

Pardon Our Interruption...

 

Running 245/40 R20 95W stock

maybe to these mentions I should try 245/45??

 

I’d stick with 245/40 r20. That’s what came with the car originally and going to a 245/45 r20 is an increase of 3.5% in overall diameter and anything above 3% change is not recommended with even 3% kinda pushing it.

 

I own two 2019 CT6 Platinums. One has 19 inch and one has 20 inch wheels. Its a massive difference in ride quality. We're looking into changing the 20 to 19s or installing taller tires but not sure how that will affect electronics.

 

Have a CT6 platinum 3.0 TT with stock 20” wheels. Was thinking of adding 22” aftermarket wheels. Anyone done this yet?
I know most would frown on doing so…given the obvious ride quality etc. I’m more worried about other concerns such as causing issues down the line with the overall suspension.
Now, having said this, it’s only a 2” difference, but would love to hear from someone that has more facts regarding aftermarket wheels vs leaving the manufacturing wheels that they designed for it etc, If that makes sense…lol.
Thanks all!

View attachment 652145


These are the stock wheels.

View attachment 652146


rims I am considering

I agree with other comments on this forum - DON'T DO IT. Cars today are finely tuned with specific tire sizes which impact ride quality, suspension, braking, computer network that ties everything together and changing a major component like will affect your traction control, ABS, top speed etc etc.

 

I drive my CT6-V in Europe and could not reach my top speed of 175 mph on anything other than the standard fit - I would not screw around at high speed with different rims but if all you are doing is driving around the city at 40 mph then I am not sure you will have any other issue than a harsher ride. But.... what do I know?

 

“This site”…. What a load of 1st post crap.

 

Pakistani scammer. Permagonzo. Troops, be very careful with your money. Thanks for the heads-up.

 

A company near me sells tires and repairs wheels, whenever I go there at least two cars are outside waiting for the larger aftermarket wheels to be repaired. The common 22" wheels with 35 series tires and 24" wheels with 25 series tires usually get bent hitting pot holes at speed because the thinner tires don't protect the wheels as well as the thicker tire series do. The usual three piece wheel design is repaired by ordering new inner and or outer barrels when the bends are severe and the center section is reused, the entire wheel doesn't need to be replaced. My CT6 has the factory 19" wheels with 45 series tires and I plan to buy a set of three piece 20" wheels with 40 series tires for summer use, the roads around here have too many pot holes to go larger regardless of ride quality.