I Have My MC On 18” Limited Choppers But I Wanna Go Up To 20” Irocs Of Swangers. And I’m Not To Sure On What Tire Size I Should Get For What? And Which One Would Look Better Having A Hard Time Deciding I Have A Sliver 2002 Monte Carlo

 

I think you want 245/40.. Maybe 245/35?? I think..

 

I used to run 245/35/20 on my 08 Impala. It was a pinch taller than stock, but very close.

IMO a 245/40 is too much, I think that's almost an inch taller than stock so you'd throw off the speedo, etc. Probably would help soften the ride a bit though, those 35s were rough!