Tire size

[homie3186]

I have a 2000 ford lightning and i was curious if i could put a 275/45/18 tire on the factory wheels. i know the factory size is a 295/45/18 but a buddy will give me his set of nittos

 

[Darren5.0L]

They would be small and narrow for the truck but would physically fit the wheel. Your speedo would not read correctly either.

Tire Size Comparison
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
295/45-18 5.2in 14.2in 28.5in 89.4in 709 0.0%
275/45-18 4.9in 13.9in 27.7in 87.2in 727 -2.5%

All that said I wouldn't bother, you will experience compromised traction, handling, and braking. In addition your cruising fuel economy will suffer (a little) from the smaller tire increasing your rev's per mile.