GM has taken a shamefully long time to design larger replacements for the Chevrolet Blazer, GMC Jimmy, and Oldsmobile Bravada. But we're impressed with early-production models we drove recently.

First, the name changes: from Blazer to TrailBlazer and from Jimmy to Envoy. The Bravada name remains, but the Olds division won't; still, GM says the Bravada will be on the market for at least two years. We drove them all on snaking, cratered two-lanes ideal for exposing powertrain, steering, and chassis weaknesses.

GM offers class-competitive power and torque with but one engine choice: a 4.2L/270-hp all-aluminum DOHC inline-six. Matched to a four-speed automatic, it pulls grades with the ease and smoothness we've come to expect from big V-8s. But the tranny falls behind the latest industry standard: the competition is shifting to wide-ratio, five-speed automatics for crisper engine response, low-rev quiet, and better highway economy. The interiors are also a huge improvement over the existing models.

Ride quality in these full-frame five-passenger SUVs is big-car smooth and solid, though the steering on the preproduction units was a little vague. The standard coil-spring suspension on the Chevy and Envoy weren't damped sufficiently, causing excessive rebound over very bad roads. No problem on the uplevel Envoy, which features rear air springs and higher shock damping rates, a setup that's also standard in the Bravada. Full road tests to follow.