Right Front (outer edge) Tire Wear

2001 Blazer 2WD. !00,00 miles. Car has had two alignments. Trusted mechanic of 30 years can find nothing wrong with the mechanics, i.e., he has looked at everything, several times. He changed a rear tire to front to see if it could just be a bad tire, but that one wore the same. Caster, Camber, tow in, tow out, all alignments meet specs. The 100,000 mile shocks were replaced. Can anybody help?

Truthfully, I think that it is time to stop trusting your mechanic.
His alignment equipment may be in need of calbrating, or alignment might not be his speciality, or–even more likely–you have wear issues with front-end components that he is not noticing.

I suggest that you seek the best alignment shop in your area. Take the vehicle to them, describe the problem, ask them to examine the front-end carefully, and allow them to give you their diagnosis.

Do you often tow a trailer? Or maybe carry a somewhat heavy load at the rear(behind the rear wheel wells)?

I had the same issue with a 3/4T 4WD truck I own. Odd tire wear. Took it in to have an alignment and it all checked out good. The tires were still wearing funny. I took it in to have them rotated figuring this was the nature of the beast and I would just have to live with it. When they jacked it up, the lower ball joint was bad… Really bad. This was the same shop that did the alignment. The alignment checked out on the machine but was thrown off as soon as it was back on the ground. So, my suggestion: check (or have checked)and replace your ball joints as necessary…

Outer edge tire wear is caused by too much positive camber or too much toe-in. With the latter, both tires usually suffer if this is the case, not just the one.

Did you get a printout of the alignment specs? If so, look at the camber spec on the RF very closely.

It’s also possible to have suspension component wear and the alignment specs may show normal because the vehicle is stationary. Once moving things may start squirming around.
It’s also possible for a component to become tweaked a bit due to a large pothole, curb strike, collision, etc. and be overlooked during an alignment if the person doing the alignment is really not on the ball.
Damage like this may not even be noticeable to the naked eye at all.

You might take a tape measure and do this. Measure from the back of the RF wheel rim (not the tire) to the front of the RR wheel rim. Do the same on the other side and compare the measurements. They should be very close. If the right side is less than the left it’s possible there is suspension damage on the RF, likely a control arm tweaked, etc.
Hope that helps.

a good alignment tech can “read” the tire wear. toe usually scuffs the tire [feathered wear] and camber is smooth tire wear. even if all components are good and the alignment is set to factory preferred specs improper tire wear can occur.
if the tech “reads” the alignment he could actually adjust it out of spec to compensate for the improper wear. we do this in our shop a few times a year.

because it is the rt frnt I think you hit the nail on the head with curb strike. bent arm on one side, everything else fine.

Have your mechanic check the ball joints with a floor jack under the control arm. This is the only way worn ball joints will show up during a pre-alignment inspection on this vehicle, and it’s amazing how many people don’t know this. You probably have worn ball joints and will be looking at $400-500 to replace all of them. Very common on this vehicle. Maybe you can then get another alignment as a good will gesture from this guy for missing the ball joints the first couple times around.

GM used to have a wear indicator built into the ball joint, I don’t know if they still do or not. But there is another way to check all the suspension components that rally works. With the wheels on the ground, have someone turn the steering wheel back and forth rapidly through an arc of about +/- 1/8th turn from centered. Under this stress, a loose component will show right up, including ball joints.

With this vehicle, I’d suspect a worn idler arm, its commonly overlooked.

Thanks Everyone. I think I’ll start with a second opinion from the best alignment shop I can find. I looked at the alignment specs printout of a year ago, which is when I started noticing the wear. Before adjustments, the left and right front showed caster and camber in spec. However, both casters showed very close to the high end of the spec and was not adjusted. The tow on both sides were 0.34 and 0.35 degrees respectively. This was adjusted to left at O.05 and right to 0.03 degrees. Cross camber and cross caster were
-0.4 and -0.5, respectively. Tow was adjusted from a total of 0.69 to a total of 0.7. If anyone would like to see this printout, I can scan it and email it to you. (johnrerika@bellsouth.net)

I should mention that a noisy right front hub was replaced during this period, but I don’t think this would have any bearing on the problem.

I think both the cross caster and the cross camber are too high. I think this indicates that there is still an alignment problem with the right front - even though you didn’t tell us what the values were.

My experience says that the published alignment tolerances are too wide. Not the target value, but the allowable deviation from that value. I think it ought to be half of what is published.

Put another way, the alignment should be within the inner half of the spec.

With cross camber and cross caster values as indicated, you’re not within the inner half of the spec.

And I disagree that replacing a hub has no “bearing” (I made a joke! Ha, ha!) A bad hub can cause a ton of related problems.