My '06 Lariat came with 20" wheels (I bought used in 2008). Can I put 18" Wheels/Rims on it?

 

Yes, if you don't want to have to recalibrate the speedo, get an 18" wheel with tires the same diameter as your 20s. I think the stock size on the OEM 20s is 275 55 20

Tire size Calculator

 

Thanks - so a 275/55/20 would fit an 18" wheel? I thought it would have to be a 275/55/18(or something to that affect)...??
ETA: So to keep the Speedometer accurate I would buy a +2 tire (or 20" tire) - correct?

 

NOOO! You will have to get an 18" tire, but if it is not the same height as your 20" tire, your speedometer will be off unless the PCM is recalibrated. It will be a completely different size to be the same height. There is a sticky at the top of the tire and Wheel forum where you can compare heights of tires.

 

Exactly like Jim said.... the diameter of the tire height, not the wheel diameter.

A 275/65/18 , 265/65/18 or 255/70/18 will get you very close to the same tire diameter as your current 20s

 

Got it. Thanks...

 

265/65/18 was the factory size for 18's I believe.

 

I run 285/60/18's which are slightly taller, but not significantly so.

 

Yeah - I'd be looking for something similar in Diameter to a 20" wheel stock. I currently have 275/55/20 on 20" rims and am thinking about switching to 18" rims. I want a tire size that would be equivalent to the 20" tire so that I do not have to recalibrate my speedometer - by the way, is recalibrating the speedometer a big deal? Hard to do?

 

It involves programming the PCM so yes without a programmer you would be forced to go to the dealer most likely. The sizes I listed are very close and by that I mean .3mph off at 60mph. So it really wouldn't be noticeable.

 

They're actually 275/65/18's