That is such a horribly bad idea I don't know where to begin. I used wheel spacers before when I was young and stupid, ... Well, ... Not educated, and I had constant problems with wheels coming loose, and the car was miserable to drive. Since then I became a suspension and alignment specialist, ten of those years at a very nice family-owned Chrysler dealership. Now that I understand how the geometry was designed for all those parts, I would never do anything again to any of my vehicles, including some '70s Mopar muscle cars, that would change that relationship.
The main alignment angle I'm referring to is called "scrub radius". If you stand in front of your truck and look back at the wheel and spindle, draw an imaginary line through the upper and lower ball joints. Those are the two steering pivots for the spindle. That line intersects the road surface at a carefully calculated point somewhere near the center of the tire tread. Rolling resistance makes a tire scrub when going down the road. The result of that is the right part of the tread wants to drag and pull that entire wheel and tire to the right. The left part of the tread wants to pull the entire tire to the left, and those two forces counteract each other. When you hit a small rock or bump in the road, that puts extra pressure on that part of the tread, but its effect is very small compared to the two equal forces on the other wheel. At worst you'll have a little "road feel", but the other tire will prevent a big movement in the steering linkage and wheel.
When you install wheels with a deeper offset, wider wheels and tires, or taller tires, you change where that scrub radius line intersects the road and tire tread. Now you will have a much higher percentage of tire tread outside that point. Look at the left tire for example. You moved the tire more to the left, so there's perhaps 80 percent of the tread pulling to the left and only 20 percent pulling to the right. You can get away with that as long as the right tire is doing the same thing. The two tires will balance each other out, as long as you're driving on a perfectly smooth and perfectly level road. As soon as you add the normal roughness to the road surface, and as soon as you notice that all roads lean to the right so rain runs off, you'll see that there are rarely equal forces acting on all parts of each tire. Now if the right edge of the left tire hits a small bump in the road, it lifts the tire and there's less weight on the left 80 percent of the tread. The 20 percent that's pulling to the right adds to the 80 percent of the right tire that's pulling to the right. That bump in the road won't last long enough to cause the truck to pull in that direction, but it will jerk the steering linkage and steering wheel. Maybe you can put up with that for the few miles driving back and forth to work, but on a longer trip it gets real tiring to drive.
Those equal forces on each tire are a major contributor to reducing steering wander. If your truck is a four-wheel-drive, you have enough to worry about with track bars and steering gear boxes causing steering wander. The last thing you want to do is aggravate that. Any time the left tire hits a bump with the entire tread, scrub radius is going to make it pull to the left, and that can be enough to bump the steering linkage to one side where it will tend to stay until you pull it back to center. You'll be correcting the steering wheel constantly. That's where the truck gets to be tiring to drive.
You also have to worry about lawsuits. Of course there's the obvious one when a wheel falls off, rolls through an intersection, and crashes through the windshield of another car, killing the driver. In that case the driver who lost the wheel didn't have much insurance coverage, so the dead driver's estate sued Chrysler because the windshield wasn't strong enough to withstand a flying tire from a GM minivan. People will sue for anything and to get out of anything. What is less-known but just as common is you can end up in a courtroom when the other guy caused the crash by running a red light. An insurance investigator or a good lawyer WILL convince a jury that you were partly at fault for the crash because you were less able to avoid it, and they will be right. Altered ride height is another thing they look for. Both ride height and scrub radius are major contributors to proper handling, braking, and steering control. The automotive marketing business is extremely competitive. We buy cars because that one has more cup holders, or that one advertises "driving excitement", at least until you have to make the first payment or pay for that first outrageous repair bill. You can be sure that if a manufacturer could build a truck with a lift kit, or add wider wheels, in a manner that didn't compromise safety even just a little bit, they would do it because that would translate into more sales. There's dozens of reasons they don't do that, and I only know half of them. You are 100 percent guaranteed to degrade your truck's safety characteristics by making any alterations, and no matter how small and insignificant those modifications are, you can be sure they will be brought up in the trial when the other guy's lawyer is trying to shift some of the blame from his client to you.
Knowing this, and having to cover my butt when working on people's cars for over 25 years, I make sure that all of my cars have the correct wheel and tire sizes, and they're at exactly the correct ride height. I have a few Dodge Challengers with easily adjustable front torsion bars. It would be easy to lower the front to make it look like a race car, and I'd love to add wider wheels and tires, but it's not worth the risk. It doesn't matter how carefully I drive. It's that other guy I have no control over.
Finally, be aware that the center plate of all original wheels is positioned in such a way as to place the truck's weight directly over the center of the wheel bearing assembly. (On older cars and trucks with tapered wheel bearings, the weight was placed over the larger inner bearing because it was its job to support that weight. The smaller outer bearing just holds the wheel straight). Moving the center of the wheel and tire outward, even a little, allows the wheel to make the spindle act like a lever that puts a twisting force on the bearing. With that larger bearing, that added force usually won't cause it to come apart but it will accelerate how soon it becomes noisy and makes a humming sound.
Monday, November 18th, 2013 AT 12:53 AM