by Pat Goss
There’s a big new problem out there that affects a lot of drivers, and that’s where the car doesn’t roll as smoothly as it should. You get a little shake or vibration either in the steering wheel or through the car. You’ve done all of the normal things. You’ve checked balance, maybe a couple of times. You’ve checked tire pressure, you’ve had the suspension checked on it and an alignment, but it still isn’t as smooth as it should be.
Well, keep in mind that modern cars are very sophisticated. Suspensions are tighter, steering is tighter, tires are lower profile and wider. These cars handle better today, even garden variety ones, than high performance cars of 15 or 20 years ago. But that means that things have to be right, and that’s especially true when it comes to the tire and wheel assemblies.
Now, stop and think about it. If we were to take and mount this brick onto a balancing machine, we’d be able to balance it so that it would spin very smoothly. But you certainly wouldn’t want to ride down the road on it. And that’s the same thing that happens with your tires. They may not be perfect.
Now, this is where the Hunter 9700 road force balancer comes in. This is a very ingenious piece of equipment. Now what it does is while it’s going through its test, there’s a roller that comes out against the tread of the tire and applies 700 pounds of force to the tread. Along with that there are micro-sensors that sense variations in the rolling resistance of the tire, or if it happens to be out of round or improperly balanced. It also checks balance at the same time.
Here we have one that the road force is excessive. Now, what you do next when you have one of these balancers, the balancer will tell you where to put a mark on the tire and a mark on the wheel. Now, I’ve actually taken the tire right off of the wheel so we can see this better, but the mark on the tire, you simply break the tire down, rotate it until the two marks line up. Now you re-inflate it, put it back on the machine, recheck it. You’ll probably be within specification. You re-balance it, and the problem is gone. It’s an amazing piece of equipment. So if your car shakes or shimmies, look for the 9700.