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What Makes a ZR2 Different From a Regular S-10

There has been a whole lot of discussion on the topic of what the real differences are in a ZR2 (GMC Highrider) and the S10 (S15/Sonoma)-4x4. To get to the bottom of this, a little research was in order.

Let's start at the General himself.

According to GM, these are the specs for the ZR2 package:

  • RPO ZR2 only full ladder-type frame with modified suspension mounting points which provide:
    • 100mm wider track (3.9 inches wider than regular S-10)
    • Three-inch suspension height increase
  • Enhanced front (7.25" ring gear) and rear (8.5" ring gear) axles w/ 3.73:1 rear-axle ratio
  • Larger wheel and axle bearings
  • 31 x 10.5R-15 LT/C black wall off-road tires (BFG A/Ts on pickups and BFG Long Trails on BlaZeR2)
  • 46mm gas pressurized Bilstein Monotube shocks
  • Rear axle track bar (pickups) / rear sway bar (BlaZeR2)
  • Wheel flares (black on Chevrolet/body-color on GMC pickups)
  • 33mm (early model) / 28mm (late model) front anti-sway bar
  • Skid plates (Aluminum through 1998 model year, carbon fiber thereafter).
And painful as it may be, for 2004, you could even get a 2 wheel drive ZR2 Blazer!

I went to the Factory Service Manual which conveniently provided the following drawings and measurements for the ZR2 vs. S-10 4x4 pickup.

The drawings below show that width differences are miniscule. Although the measurements aren't all at the same places, where the same reference points are used, the measurements are the same.


At the front cross member, there is aproximately 50 mm (just under 2 inches) difference. The Z hangs lower here.

Comparing lengths shows virtually no differences.

So we discover that the basic frame has some differences, primarily in the mountings associated with the first crossmember and where the control arms mount.

I lucked out and one of my neighbors bought a 2001 Chevrolet Blazer and allowed me to take some measurements and pictures. I also took comparable pictures of my 99 ZR2 Blazer to see if we could find other differences.

These next 2 pictures are looking at the driver's side rear wheel. Notice the differences in the springs and in the size of the rear differential. You may also notice the Blazer's 235-75x15 tires and the ZR2 Blazer's 31-10.50x15 tires (which had been switched to BFG AT/KOs from the factory Long Trails).

These next 2 pictures show the body mount at the front of the door. Driver's side on the Blazer, Passenger side for ZR2. You can see some difference in the relative position where the LCAs attach as well.

If you look closely in these next 2 pictures, you can see the difference in the front sway bars and, more noticeable, the difference in height which at this point is largely due to a difference in tire sizes.

These next two show the forward rear spring hangers on the passenger side. No visible differences in the hangers themselves but there is a difference in the springs, as the eye of the ZR2 spring sets below the leaf while the non-ZR2 eye sits above.


These two pictures were intended to compare the differences in the halfshafts but this picture doesn't show a difference.

Engines, transmissions, transfer cases are the same.

Front differential is the same.

Rear axle: ZR2 has a 8.5 inch ring gear and is a shortened version of GMís full size 10-bolt. The ZR2 also has the Locking rear axle as part of the package. Blazer has the 7 -5/8 inch ring gear as found in all S-10s (except the ZR2) It can be had with a locking rear axle as well.

The frames are unique to the ZR2. The front suspension, while similar in design to the Blazerís, uses different control arms and CV half shafts. The ZR2 also comes with Bilstein HD shocks standard. Standard wheel size on the 4x4 models of both is 15x7. The Blazer uses a 235-70R15 tire. The ZR2 came standard with 31-10.50x15 tires. (this changed to a similar metric size beginning in 2004). These tires will not fit on the Blazer without an additional aftermarket lift lit.

The grill, hood, glass, doors and rear gate and hatch are the same.

The front fenders are unique to each, as are the rear quarter panels. The front fascia is unique. The rear bumpers are unique to each. The ZR2 includes the larger fender flares.

In a comparison of 2004 models, the ZR2 package added $2000 to the MSRP of a Blazer.

The comparison of 2 Blazers side by side and the FSM dimensions for the extended cab pickup lead to the conclusion that there may be some value in using ZR2 parts (such as springs and/or control arms and half shafts) is obtain small amounts of lift for your S10.

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Last Modified: October 05, 2006 JDM