2013 - Expee Max from fothco

[fothco]

My , my - dropped sparetire ; had to pressure it up ! And service it . Why is it 18" rim when suv has 20 " . Plus Pirelli-Scorpion tire; the suv surely did not come to me 2nd hand with Pirellis !! Can I run 18" spare if we get a flat tire . ? Fothco

 

[Flexpedition]

The 18 spare is fine, the overall diameter is the same. Your spare tire has a taller sidewall. Its a full-size spare, run it as needed.

 

[Adieu]

My , my - dropped sparetire ; had to pressure it up ! And service it . Why is it 18" rim when suv has 20 " . Plus Pirelli-Scorpion tire; the suv surely did not come to me 2nd hand with Pirellis !! Can I run 18" spare if we get a flat tire . ? Fothco

Tire sizes use a bizarre mixed multi-measurement format:

width millimeters / percentage of width sidewall & inches rim

So 265/55r20 for example is 265 mm wide, 55% of that tall, and on a 20" rim


Calculate diameter for ***/YY r ZZ tires:
(*** * 2 * 0.YY) + (2.54 * ZZ)

Compare the two, if within a couple percent of each other it's useable

Brands and rims can be mixed at will in dry good weather and slow speeds, but be careful running a mix of heavy steelies and/or LT tires with light alloys and light P tires or extremely different treads in bad traction conditions & high speeds.... LT/steelie combos can be a whoping 40lbs ea. heavier than P/alloy combos of roughy the same size, so stability CAN be compromised