rodsf150lariat

Looking at a truck to purchase and noticed it has 18" wheels installed from the factory (per original sticker). Truck has max tow and 3.73 gears. My question is: Will the smaller 18" wheels have any effect on mileage or the max tow capacity? I thought all max tow packages came with 20" wheels?? Any assistance would be appreciated.

safetypin

they won't have much difference at all by way of mileage or tow capacity.


more sidewall will allow for more body roll in corners, and might be smoother, but that's about it.


18" vs 20" is a style option. functionally, they both bolt to the wheel hub and have a tire on them. either way is fine. OEM wheels are stout, I'd not worry.

rodsf150lariat

I was thinking that a smaller tire would have to spin faster to go the same speed as the 20" thereby effecting rpm which is the advantage I am gaining from the taller gear. Am I wrong??

I guess it would be also safe to assume since it came from the factory that way that the speedo is calibrated correctly.

MattXLT

Overall tire height (diameter) is going to be roughly the same regardless of factory wheel diameter give or take an inch. (Raptor being the exception) Bigger wheels have lower profile tires (aka less rubber on the sidewall) while the smaller wheel will have more tire sidewall.

safetypin

You're right - it would be spinning faster, but it would also take less power to turn than a larger wheel/tire combination. Look at the tire/wheel combo rather than just the wheel.

DBL Boost

20s came on lariat chrome package. I have seen 18s on multiple lariats.

Bigbirt

Is the tire really smaller? You haven't posted the tire size... You can get a 35" diameter tire on a stock 17" wheel. The tire determines the overall size, not the wheel.

rodsf150lariat

Tire size is: 275/65R/18

Scarlet

The Lariat, in most cases, had two tire/rim sizes. 275/65-18 was standard, 275/55-20 was optional. But the "Overall Diameter" remains almost identical. I think the Off Road package had 275/65-18? The Raptor had 315/70-17. If you use a Tire Size Calculator, you would find the 18" combo at about 32.07", and the 20" combo at 31.91" diameter. So both the 18" and 20" tires are about 32" Diameter. The difference being the Raptor with about 34.36". Hope that makes it a bit clearer for you.