ΔE 11.3, fair: the same colour family, but not a straight swap. Mechanicus Standard Grey is a little lighter, more muted than Rubber & Tires.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Mechanicus Standard Grey is a little lighter, more muted than Rubber & Tires.
The same difference applies the other way round: Rubber & Tires is a little darker, more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Rubber & Tires on the colour wheel See Mechanicus Standard Grey on the colour wheel
All matches: Rubber & Tires equivalents · Mechanicus Standard Grey equivalents