Can This Gizmo Pull You Out of a Skid?

Stabilizer bolts to frame below rear bumper. On some cars, special mounting brackets are needed.

Our automobile experts, Jan Norbye and Jim Dunne, try out the lnsta-Matic stabilizer and give you their conclusions on it.

Would you pay $120 for a device that controls your car on curves, stabilizes it on straightaways, increases traction, and reduces skidding, body sway, braking distance, abnormal tire wear, and driving fatigue?

These are the claims made for the Insta-Matic auto stabilizer. But how good a job do such devices do? We decided to test the Insta-Matic and find out if it does any of the things claimed for it.

The tests. First was lane changing two lane changes within 180 feet after speed was built up with five or six practice runs.  Maximum steady speed without the stabilizer, 67 m.p.h. With it, 68.

WITHOUT: The front wheels "plow" at a high steering angle as the car is aimed from left to right lane, while the rear wheels trail obediently. Maximum steady speed in making test was 67 m.p.h. WITH: The tail end begins to drift out as the front wheels are aimed toward the right lane, sending the car into an oversteering attitude. Maximum steady speed in making this test was 68 m.p.h.

Next test curves. We took a long curve, about 300-foot radius, with an entry speed of 70 m.p.h., and measured elapsed time from a post just before the curve to another at its end. Two runs without the stabilizer were timed at 7.4 seconds each. Two runs with the stabilizer installed gave the same results, but the car felt different. To explain this:

Letís look inside. The stabilizer is a long, closed tube with a heavy iron slug inside. By moving left or right, the spring-loaded central slug is supposed to counteract instability of the carís tail end. Does it do a good job? No.

On the Cutlass (standard understeer), the "stabilizer" introduced an element of oversteer. Normally, the front wheels lose side bite first in extreme situations. A driver compensates for this by backing off on the accelerator and taking the turn at lower speed.  With the stabilizer installed, the rear wheels break away first, calling for steering correction.  Backing off on the throttle is not enough.  You have to countersteer, too, because the stabilizer has in fact put the car in an unstable attitude.

In a low-speed traffic weave between cones spaced at 48 feet, top steady speed was 25 with and without the stabilizer.

We did not test braking distances. We felt we could not isolate effects of changes in disk, drum and tire temperature, or road condition from any effect the stabilizer might have. Nor could we find any logical reason why the slug, with lateral travel only, should influence fore-and-aft weight transfer (the major cause of rear-wheel locking).

Conclusions.The Insta-Matic has negligible effect during lane changes, no value in high-speed cornering, and no effect in low-speed maneuvering. The photos show what little effect, if any, the device has on body roll (sway).  If it improves traction any, it can only be due to its added weight on the wheels.

Driving fatigue?In normal traffic, the stabilizer makes no difference at all.  Finally, can it pull you out of a skid?  We donít think so.  From our experience, we would say the slug is too light to change a skid in any way.

WITHOUT: In the middle of a fast curve, the steering angle again is high as the car attempts to revert to a straight path with the rear wheels following obedietly behind those at the front. WITH: On the same curve and at the same speed, the carís rear wheels are now drifting out and the driver is countersteering. Body sway appears to be more pronounced than without the stabilizer.
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