Pickup was not really pulling, but more like drifting to the right. I was due for a rotation so I also got an alignment. He asked me after they got done if it was pulling to the right. He said the tow and camber was fine, but that the caster on the right side was half a degree or so lower than the left. He said they usually put the caster half a degree higher on the right to compensate for the crown of the road. So they did.

When I drove it home it seemed to be drifting kinda to the left now. My question is is it really necessary to do this at all and is it common? I got the impression that tow and camber will cause more tire wear than caster.

I work for a DOT and when we do an asphalt overlay we're lucky to get half the crosslope or crown back. Even with all their fancy electronic controls on the screed alot of times the crown is almost nonexistant except for a totally new road.

 

The truck will pull to the side with the most negative caster. I've never adjusted for road crown, at least around here I never thought it was bad enough to take into consideration. Caster is also a non-wearing angle, it only affects handling and steering wheel return. If you've got a slight drift, I'd kinda be thinking radial pull in the tires. I would have switched the tires from left to right (assuming the alignment was within spec) and see if it changed any.

 

I've heard of shops doing that before, but I don't buy it and I'd hurt 'em if they ever did it to mine.... For mine, make it all the same (or as close as humanly possible) so it tracks straight down a straight level road. If the road slopes left, I expect to counter-steer right just a bit. If the road slopes right, I expect to counter-steer left. I HATE when a car drifts to one side or the other.

Besides, say they compensate for the crown to the right. What happens when you're in the left lane of the freeway? (I.e. road crowned to the left). Now the pull is TWICE as bad as if they had just done it right the first time and made it track straight.

-Joe

 

I agree with you Joe. I didn't fully understand their reasoning either and I didn't fully understand the three adjustments involved in an alignment.The main point of the alignment was to make sure that I was damaging the tires. They are expensiiiiiveeee.

Anyways caster is a non wearing adjustment, so yes it is annoying, but I learned my lesson. Next alignment I will tell them to set the caster the same, I don't care about the crown.

Funny I was driving on a street with a pretty good crown on it this evening and it still went to the right even though they say they set it up to counteract the crown.

 

i asked for it to be set to specs when i had a alignment. i drive on the interstate alot so it doesn't really have a crown. i have heard of them adjusting for the crown though.

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Good advice all. I have had many alignment issues with mine, all my own fault, my truck sits very low. I have also heard of compensating for road crown. I also set mine neutral because I kept having it pull one way or the other and got tired of it. Now it only pulls if the road IS crowned in some way. I ended up using my own settings and going to the alignment shop multiple times to get it just the way I wanted it. Got to have great handling and no tire wear.

And yes the two biggest tire wear offenders are toe and camber.

 

Acutally all roads have a "crown". I am a civil engineer. The "engineering term" for it is cross slope. Every road has a cross slope of somewhere between 1% - 2%. Paved shoulders are more, maybe 3% or so. This is so the water runs off the road when it rains. Asphalt roads due tend to "rut" after a while so sometimes the slope doesn't do any good because the water stays in the "ruts". This is due to poor sub-base or a poorly designed or layed mix.

A standard lane is 12 ft. Your standard two lane US or state highway is 24' or 30' wide since some have a 3 ft shoulder. Also some two lanes have paved shoulders 7' or 8' wide.
So lets see: 15' x 1.5% = .225 ft = 2.7 in. A 2.5 inch slope in 15' is almost impercievable while driving. I seriously doubt that your vehicle will tend to go to the right from this. Set my caster the same.