1ST GEN. GUYS:
Allow me to offer some info on replacement wheels for the '88 - '93 trucks.
I'd suggest you stick with a Zero offset wheel, with a back space dimension of 4" to 4 1/2". , not wider than 8". This comes from 152k miles of experience. Your suspension and wheel bearings will like you for it.
the 2nd Gen. trucks have wheels with a severe backspace dimension, similar to a front wheel drive car. This is to allow for the sealed "lifetime" bearing unit design on the front axle. The wheels, if placed on a 1st. gen. truck would have the effect of the center hub staying in place, while moving the wheel rim and tire toward the inside of the truck.
In short, the 2nd gen. wheels are made to accomodate the "new improved" axle design, and still stuff the tires within the fenders, by back spacing the wheel hub. They MAY fit the bolt pattern, and they surely will look odd, and probably would whack the front discs.
The 1st. gen trucks have a 6 1/2" x 8 lug pattern, with 1/2-20 rh lugs.
the 2nd. gen. is 6 1/2" x 8 with 9/16 lugs.
Wheel backspace is the distance from extreme back (inside) edge of rim, to the mounting pad.
Wheel offset is the distance from the wheel's centerline to the plane of the wheel hub. Zero offset is the center of the rim.
This is offered as a help before you spend your hard earned cash. Check aftermarket good quality wheels, like American, or Mickey Thompson, before you lay it out for D/C.
Regards.
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92cum'ns 5spd 4wd all possible mods. to void warranty.