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Discussion Starter #1
I have an '18 Impala Premier with the 20" wheels. I had the misfortune of bending two of them when I hit a pothole in Indiana. Repairs done at the local stealership were unsatisfactory. I am considering buying four new 18" stock wheels and 245/50 r18 tires which are really close to the same diameter and width of the 20" stock setup. I'll keep the twenties and tires in case I ever want to trade the car in. I figure the 18" wheel/tire combo will give me some sidewall flex the 20s don't have, as well as replacing the damaged/straightened wheels.


My questions: Will this wheel/tire combo clear the struts at the top and fit well around the brakes? Can the pressure sensors be switched from the old tires to the new? I had that done on another car I had with no problem.
 

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That must have been one gigantic pothole. As for answering your questions, sorry I have no idea but would start by comparing part numbers for the premier vs the LT with the 18 inch stock wheels. Good luck and maybe some others on the forum can provide more information.
 

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The 18" wheels will fit as the Impala LS already uses them. Struts, Brake Rotors & Calipers are the same across the board on all models of the Impala. Pressure sensors can be moved to the 18" wheels.
 

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I've got a set of the same wheels, 20's if you are ever interested in them, have 5000 miles. Got a new chrome set. Would sell the entire set for a great deal...
 

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i know on the police calipers when they were upgrading brakes on 8th gens it would say "17" on the caliper itself indicating it needed at least a 17 inch rim to clear the brakes. i would pull a wheel and look for such a marking before buying a different set of rims.
 

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i know on the police calipers when they were upgrading brakes on 8th gens it would say "17" on the caliper itself indicating it needed at least a 17 inch rim to clear the brakes. i would pull a wheel and look for such a marking before buying a different set of rims.
There is no police version of the current Impala. The calipers are the same no matter what trim level. The car comes from the factory with 18" wheels. The Rotors, Calipers & Suspension are the same weather it's a LS, LT, LTZ or Premier.

I would get Factory 18" wheels if you can.
 

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i know on the police calipers when they were upgrading brakes on 8th gens it would say "17" on the caliper itself indicating it needed at least a 17 inch rim to clear the brakes. i would pull a wheel and look for such a marking before buying a different set of rims.
As bowtie has already stated, all brake and suspension components are the same across the board for all trims. All you need to do is swap the rims and make sure the tire size is correct.
 

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I have an '18 Impala Premier with the 20" wheels. I had the misfortune of bending two of them when I hit a pothole in Indiana. Repairs done at the local stealership were unsatisfactory. I am considering buying four new 18" stock wheels and 245/50 r18 tires which are really close to the same diameter and width of the 20" stock setup. I'll keep the twenties and tires in case I ever want to trade the car in. I figure the 18" wheel/tire combo will give me some sidewall flex the 20s don't have, as well as replacing the damaged/straightened wheels.


My questions: Will this wheel/tire combo clear the struts at the top and fit well around the brakes? Can the pressure sensors be switched from the old tires to the new? I had that done on another car I had with no problem.
I switched out the 20" wheels for 18" wheels when I took delivery of my 2019 Impala earlier this year. No issues. No regrets.
 

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I am considering buying four new 18" stock wheels and 245/50 r18 tires.
Tirerack lists the proper size for the 18 Impala as 235/50-18. Anything over sized is a risk you would have to assume. Probably not going to find the proper answer here.

Here is the sizing info from Tiresize.com as a comparison of 235 vs 245.

Diameter
27.3" 235
27.6" 245
+1.1%

Width
9.3" 235
9.6" 245
+3.2%

Sidewall
4.6" 235
4.8" 245
+4.3%

Circum.
85.6" 235
86.8" 245
+1.1%

Revs/Mile
740 235
730 245
-10
 

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Discussion Starter #11
ICUBB, the reason I suggested 245/50 r18 tires is that they nearly match the circumference and width of the 20" tires they'll be replacing. That will leave speedometer error at a minimum. 245/40 r20: circumference 87", diameter 27.7", width 9.6" For the 245/50 r18s, circumference 86.8" (two extra revolutions per mile), diameter 26.7", width 9.6". There is no doubt the stock twenties leave no room for anything bigger (there may be 1/4" gap between the tire and the strut), but these are the same width with a bit smaller diameter and circumference.


Thanks to everyone for the replies!
 
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