Alignment experts?
 

My Mrs's. purple pt cruiser a 2001 is running 15" american racing wheels with michelin hydroedge tires, IIRC, 215/60r15.

The right front is worn badly on the outside of its tread and the left front is not much better.

I like how it drives with these tires but am not impressed with the tire life. Is it:
1. the tires are too small.
2. an alignment problem
3. the tires are not appropriate for the minivanlike pt cruiser?

I have thought of asking the alignment shop to dial in some more negative camber and possibly adding a bigger front sway bar.

or getting wider tires,

or going to a harder more vanlike tire.

What say you alignment experts out there?

Sounds like its lighter in the nose than when left the factory.

How you figure?

I am no expert, but its like when you load a car down. The car squats (if its not solid axle), and without the aid of SLS remains squatted until unloaded. Looks like this /--\ .Tires wear on the inside, as that is where its making contact.

Remove weight, and the opposite happens. Your tires would look like this \--/ . Making tires wear on the outside.


I would talk to a tire shop. Most of them around here will check your alignment for free.

Have an alignment shop check BOTH the camber and caster...if either is out, then you're buying tires before their time...and when they're checking the specs, have someone, or something, about the approx. weight of the normal driver, sitting in the driver's seat...that way, you're taking into compensation the normal weight that the vehicles is having to deal with...along the same lines, consider the weight of gas in your vehicle...do you run the tank to almost empty before refilling? If so, then make sure the tank's half full...conversly, fill the tank to 1/2 your normal fill/re-fill point and put it on the rack...that will average the normal tilt your vehicle has to go through during a normal fill/re-fill cycle with the normal weight of the driver.

Good luck...

Also...have them check to be sure the bearings are snug to spec...I chased an alignment problem for months before I found out the king-nuts were too loose...tightened them up about a 1/16th of a turn...car drove like new and it held the alignment.

Thanks for the thoughts.

Being a front driver I don't think there is an adjustment nut for the front wheel bearings....though I got excited there for a minute!

Any other thoughts out there?

Sometimes the bushes or thrust washers go bad or the arm is out of geometry and that causes these issues. Only a good alignment shop with an expert tech doing true 4 wheel alignment can help you out. In my experience, its the tech doing it that matters most so I have my set shops in NY and in India and only patronize them.

I wouldn't go modifying the car. It certainly wasn't designed to wear tires unevenly.

The first thing to check is obviously tire pressure. I expect you had that within spec. Next is toe. Too much toe in causes uneven wear on the outside of the tire. Then camber. I don't know if the PT Cruiser has adjustable caster, but that would be the last of the three alignment specs to check.

If it drives pretty stable both at speed and in turns, it's gotta be too much toe in.

From the description of the wear, it sounds like too much positive camber, but I've seen out of spec toe cause similar wear to tires also.

Sounds like an alignment problem...either caused by worn out front end or just whacking the tires into curbs and such. Or both.

I bet its a simple tie rod adjustment.

Thanks, for the thoughts. If it were toe both would be worn on the outside, and the right front is much worse. It does not look like positive camber, but that is worth measuring, I not too long ago had Bilstein shocks installed so if there were looseness I believe the alignment shop would have noticed and called that to my attention, and I don't think the tire pressure is low but I honestly have not checked for a couple of months, so that could actually be it. If it is I will be embarressed.

Thanks again.

Could be too much positive camber or too much negative toe. Front-drive vehicles tend to pull the front wheels in slightly from the sheer force of the speed of the axles,etc. If they're setting it at ZERO toe on the rack, it's going even further into the negative at speed. Front-drivers usually spec a bit of positive toe for that reason. If it is a camber issue, MOOG generally makes "camber kits", which are essentially smaller diameter strut-to-spindle bolts to allow a little camber adjustment if it does not have any factory adjustment.

The Hydroedge carries an 80k-90k treadwear warranty; you really cannot buy tires which are any harder.

Sounds likely to be alignment. Too much toe-in will wear the outside, and/or not enough negative camber. Both adjustments move wear from the outside to the inside of the tire.

How aggressively does the spousal unit drive this thing? A FWD platform will eat front tires when driven with a bit of passion.

- JimY

Improper toe will accelerate wear far more than improper caster or camber. FWD can be harder to nail because toe changes dynamically during acceleration and braking. However, the specs are supposed to account for that. There may be more than permissible play somewhere amongst all the steering components.

Toe may be out more on one side than the other. Like gmercoleza said, toe impacts tire wear much more than camber or caster.

Probably just a typo, but speed causes the front tires to toe out, not in.