LS1[CHEVY]

Im getting some 18X9 Evos this week. I picked a 275/35/18 for the rims. Im currently running stock 16in wheels and tires. How much will my speedo be off when I put the new rims and tires on?

wickdws6bird

iTrader: (16)

just click the link and it will figure it for you.

http://www.discountpartcenter.com/tirecalc.html

AW/whiteZ-28

Not enough to have to reprogram, I have that tire size up front.

Trent

iTrader: (3)

I can't remember the exact tire size on the 16's so I did two different ones for you. Hopefully you have one of these sizes already on the car.

275/35/18 is 25.578 inches tall

245/45/16 is 24.68 inches tall

245/50/16 is 25.646 inches tall

Either one of those you will be fine with. The 275 might make it a LITTLE bit off, but as already said, not enough to make a big enough difference.

C.J.

why would the 275 tire width cause it to be off? I would guess that the overall diameter would cause the speedometer to be off so wouldnt it matter more if you are increasing wheel size or sideway size?

BrandonSS

iTrader: (1)

b/c the sidewall number is the perent of the width. like 275/35/18. 275mm wide and a sidewall 35=35% whith adds to the diameter( or radius) which in turn adds to the circumference.

So a tire that is 275mm across has a sidewall of (35%) 90.75mm which is roughly 3.8 inches. So with a 18" bead diameter + 3.8" top sidewall + 3.8" bottom sidwall = 25.6" diameter total

now that will be 25.6"*pi= 80.384" around (circumference)

SO you see if you have a say... 315/35/18 it will be taller and have a larger circumference which will make the speedo read SLOWER than the 275/35/18 but only by 4.3% or if you are going 60 that would make the speedo read 62.6mph.

LS1[CHEVY]

wow i feel like i just got a algebra lesson Very well explained . Thanks guys