Hi guys, I hope you can help me. I have a 1971 oldsmobile cutlass Supreme convertible with air shocks in the back. I just bought a 455 monster and they say I definitely need fatter tires in the back. What are some setups that would work for my car without any modifications? What is your setup? Thanks!

 

Wheel and tire size data base, please post yours - ClassicOldsmobile.com

 

I have 275 60 15 on 10” rims in the rear, same body as you, no air shocks.

 

Get rid of the air shocks and install new springs. Springs are maybe $100 for the pair and the ride will be so much better than what the air shocks will do. I had air shocks on my 70 Supreme through the later 80s / early 90s, and after installing new springs and removing the air shocks the ride was sooooo much better.

As for the rear tires, the fenderwells are wide enough to easily support a 295-50-15 tire as long as the wheels have the correct backspacing. You can very easily fit 275-60-15s and with 5.5" backspacing you can fit a 325-50-15 tire.

 

Thank you guys for the info! Which tire is the fattest one in terms of width?