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OT: Alignment Question


JasonA

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This is a question relating to the Grand Caravan we just bought, but it could happen to any of us out there I think, so I wanted to bring this up here and see if anyone has any advice. I also posted it on a Chrysler minivan forum, and I'll post any feedback I get from them here also, in case anyone is interested.

I put a new set of tires on it today, at Sears. I had narrowed it down to the Goodyear ComforTred or the Michelin Agility. The Agility is a Sears-only brand, but after calling Michelin today, I verified that it's based on the Harmony, which is their very well-reviewed general market tire. Past experience with Michelin (and with Goodyear, in fact) steered me, so to speak, towards the Agility. As part of purchasing new tires today, a free alignment check was included. Everything looked good, except for toe. The data on the sheet is consistent with itself, but not with how the van drives.

The sheet reports LF toe at -.56* and RF toe at +.67*. This means both tires are pointing to the left. Both are out of tolerance. Total toe is .11*, which is within tolerance...perfect actually (tolerance is -.10* to +.30*). This would make sense -- if both tires are pointing to the left, total toe could still be (and is) correct. They also have a "Steer Ahead" field, and it's listed as -.62*, which is consistent with the above data (indicates pointing to the left).

However, the van drives perfectly straight on the road. Looking at the data above, you would think the van would severely pull to the left. But it drives very straight. The steering wheel points straight-away, and if you take your hand off the wheel, even at Interstate speeds, it runs straight.

Could the technician simply have set it up "wrong"? Could he just have had the tires turned to the left slightly when aligning it, and getting "bad" readings? I'm not an alignment tech. at all, so I don't know if that's possible. Anyone have experience with this? Thanks VERY much! If it sounds like that's exactly what he did (set it up wrong), I'll save my 40 bucks and just watch the tire wear.

Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

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I'm no alignment tech either. In fact, some on this board might tell you that a good alignment can be had by using sticks and stings. If that were the case, it makes me wonder why there is a GM trained tech that specializes in Cadillac front end alignments and why there is so much expensive equipment sold to do the work.

But anyway, back to your problem. One factor that you may not be considering is the crown in the road. The degree of crown sometimes affects whether or not a car will pull left or right. For safety's sake, I prefer a car to pull ever so slightly to the right. That way, if I fall asleep or somehow lose control, there is less likely a chance of drifting into oncoming traffic. You may want to drive your car on several different roads to be sure what you are reporting is consistent and repeatable. But the real proof of a good alignment is tire wear. If this alignment proves to give acceptable wear patterns, and does not feather the edges of the tread, I'd be happy. Sometimes stability comes with a price. That price can manifest itself as increased tire wear and decreased fuel mileage. Both pretty hard to prove and even more difficult to correct since the damage is done before you know it. Who knows, maybe all that expensive computer equipped alignment stuff is worth it after all.

Never underestimate the amount of a persons greed.

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Total toe is what is important. The rest only affects where the steering wheel ends up. IOW turn the wheel a little and the machine won't know the difference. I wonder if they were one notch off of straight up and down when they set the wheel. This would account for what you are seeing. Regardless you don't have a problem.

HTH

John

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Thanks guys -- I tend to agree that there is no real problem here. I'm thinking of stopping by Sears one evening after work and just seeing what they have to say, and asking them to possibly re-check it, and let me watch as they set it up. Yeah, I'm sure I'm annoying to a technican that way. :)

I don't think road crown comes into play, although it's a good point. The steering on this van is pretty quick, and it doesn't take a lot of wheel movement to correct road crown tracking. Some roads are crowned heavily, and some are not at all. The steering wheel always points where it should in my experience. I paid real close attention to everything, since we had a short warranty on this van after purchase. That's why the alignment "problem" is shocking in a way, given the way it drives. I do think it may have been human error when they set the machine up, but I didn't know that was possible at the time.

Thanks again! Any further comments appreciated!

Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

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Going through the alighment whoas with my Vette, put a new rear in it 355 gear and I have a castor offset. Like you the car rolls great and straight. The tech explained to me that having the castor and toe adjusted like yours offsets the effect of the road crown from constantly pushing the car off the road. Less fight to keep it going straight. It is mormal to have some adjustment to pull the car to the left. You should notice it on slight banked turns, left turns for me I have to understeer the car and rights oversteer

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There are several other factors that might come into play here. Torque steer, even under very light acceleration, could be present....and being compensated for. And finally, rear wheel alignment. After all, if the rear wheels are even slightly out of line, say making the rear steer slightly left, the front being slightly left would compensate, making it seem like the car is going straight....however it may be "crabbing" a little.

I saw a Ford truck once that had the rear axle shifted so that the left rear wheel was slightly behind the right rear wheel. This thing looked really weird when I was following it. It was so bad that I followed the guy to tell him what was going on! He replied that the truck steered fine and he didn't think he had a problem. We looked a little closer and could see that the locator pin on the rear leaf spring had come out of its hole and allowed the axle to move.

I guess that's why 4 wheel alignments were invented.

Never underestimate the amount of a persons greed.

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Let me follow up to you guys. I stopped by Sears last night after work and talked to a different service writer than I talked to before. Basically, he said the same thing 32v_dohc said above. Total toe is inline, so I'm good. He said they could correct the tires pointing left if I wished. I said I don't know what that would achieve, since the van drives straight and the wheel is straight. He shrugged. The rear tires (solid axle) are completely straight. The toe on one was exactly 0.0* and the toe on the other was 0.1*. Camber was also dead-on. It does have a solid rear axle (one thing I disliked about all the Japanese vans is they have IRS), so about the only thing that could mess up the rear alignment is a malfunction (like what JohnnyG mentioned above) or an accident in the past.

The van drives too straight and the mileage is too close to what EPA says (it actually exceeds EPA usually) for me to believe I have a problem as serious as the spec sheet stated. The Sears guy said there was no way to set it up "wrong", but when I asked how they set the wheel straight, the guy indicated they do it visually. That's enough of an explanation for me to write this off as human error. I keep accurate enough logs of treadwear though, so I'll know quickly if something really is out of spec.

Thanks for everyone's feedback!

Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

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