I'm assuming the '99 up bolt pattern is metric, but I've also seen them on early '90s trucks, and even a '66 Suburban! How different are they, and could one use them as rollers on older trucks? Also, newer steel 6 lug Tacoma rims seem to be going for cheap on FB marketplace, did those become metric at some point? I own a '70 Suburban as well as an '81 Jeep J-10 that are both 6 lug, and only one set of really dry rotted tires on Chevy rallies. (I would NEVER drive a dry rotted tire on the street, I've personally had two explode while parked! Thanks!

1966 Suburban 6-lug: 6 x 5.5" (6 x 139.7mm)
1970 Suburban 6-lug: 6 x 5.5" (6 x 139.7mm)
1981 Jeep J-10 6-lug: 6 x 5.5" (6 x 139.7mm)
1999 Suburban 6-lug: 6 x 5.5" (6 x 139.7mm)
2020 Tacoma 6-lug: 6 x 5.5" (6 x 139.7mm)

Look at weight rating, offset, and PSI rating of each.

Hmm, that'* interesting! I have noticed the center hub hole is a lot smaller on the newer rims. The one I saw on the '66 was on the rear.

Good point:

1966 Suburban 6-lug: 6 x 5.5" (6 x 139.7mm) center bore 3.58" (91mm)
1970 Suburban 6-lug: 6 x 5.5" (6 x 139.7mm) center bore 3.08" to 3.27" (78.3mm to 83mm)
1981 Jeep J-10 6-lug: 6 x 5.5" (6 x 139.7mm) center bore 4.25" (108mm)
1999 Suburban 6-lug: 6 x 5.5" (6 x 139.7mm) center bore 3.08" (78.3mm)
2020 Tacoma 6-lug: 6 x 5.5" (6 x 139.7mm) center bore 4.17" (106mm)

Look at weight rating, offset, and PSI rating of each.