I have a 2002 Avanti Convertible. Got it in April. Have had great drives with this call in dry, in hot and in rainy weather. I am very pleased with this car's performance.
This car has 235/45Z R17 Front Tires and has 245/45Z R17 Rear Tires. The speedometer, compared to GPS tracking, appears to be fairly accurate.
The Glove Box Door has a Tire Info Plate that shows 235/45Z R17 for the Front Tires and 255/45Z R17 for the Rear Tires.
Searching for info for the (donor car) 2002 Pontiac Firebird/Trans Am Conv. at local tire stores I see: 245/45 R17 Front & 315/35 R17 Rear at Discount Tire.
I see 275/40 R17 Front & Rear at Belle Tires. I see 255/45 R17 Front and 275/45 R17 at Tire Rack. The 2002 Pontiac Firebird Owners Manual sez 275/40Z R17 Front & Rear.
When I do replace the tires on this car I suppose that I will follow what it says on the Glove Box Door Tire Info Plate ...... or ...... ???????????