20's To 17's

[SJP12]

When I got my truck new in 08 it had the 20's tires ( 255/70/R20 ??? ) Its getting time to replace the tires and I would like to go to a 17" tire/wheel combo....I like old school looks. How much differance is there between the Stock 20" tire/wheel combo vs the 275/70/R17, by differance I'm talking ride, height over look? Will my speedo be off and how much will I loose in gas mileage? The truck has a RC 2" level. Truck is a 2wd 5.3 08.

 

 

I'm looking at Nitto, Toyo or other similar AT tire.

 

Thanks!

[mhenshaw]

Stock tires are 275/55/20 and 275/70/17 are the exact same size tire. Ride will change alittle depending on tires, gas mileage will depend on tire weight. I would think gas mileage would stay the same since a/t are heavier but you are getting lighter wheel. No change in speedo either.

 

So the only difference is the wheels will look smaller and you will have more sidewall.

[old-chevy-dude]

as long as the outside diameter is the same the speedo and mpg won't change.

 

the 20s are 275/55 R20 so a 265/70 R17 would have the same outside diameter (over all tire diameter is the same) but you will have more sidewall so the ride might feel less "stiff", cornering will be softer as the tire will give more, and you might improve MPG slightly as rubber weighes less than metal and you are adding more tire and reducing the overall weight of the wheel.

 

 

if you go wider, say 285, then reduce the side % and go 65, so 285/65R17 also carries the same outer diameter size (it is actually 0.3 inches less) but won't make any major difference.

 

 

 

remember the first number is the tire width in millimeters, 285mm, the second number is the % of the width, i.e. 65% of 285 (185.25mm) so a 285/65 is 35% wider than it is tall..