alignment question
06-23-2011, 04:08 PM
#1
alignment question I got my car aligned at firestone. I didnt have an issue with the one in Iowa, but the one here in North Carolina has been nothing but issues
.
Anyways. Took the car in cause the front tires had some saw toothing on the inner edges, but the rears were fine. Car drove straight, not issues. They didnt give the before specs, like I asked for, but I did get the after specs. The wife did the leg work for me cause I was at work and she said the steering wheel wasnt straight. sure enough, I get home and drive it. Its off to the left. Doesnt seem to pull that much, maybe a bit to the right, but road around here are not the best. The issue I have is the thrust angle. The rear toe says -.20 on the left and .16 on the right, and gives me a thrust angle of -.18.
They claim it is not fixable. I know the rear is not adjustable, but they could counteract it with some toe adjustment correct? The spec is -.15 to .15, so its only .3 adjustment. I looked under the car and the trailing arms look to be in good shape. thats the only thing I could think of that would throw off the toe. anyone else? could he just not of bounced the car and it was giving a false reading?
. Anyways. Took the car in cause the front tires had some saw toothing on the inner edges, but the rears were fine. Car drove straight, not issues. They didnt give the before specs, like I asked for, but I did get the after specs. The wife did the leg work for me cause I was at work and she said the steering wheel wasnt straight. sure enough, I get home and drive it. Its off to the left. Doesnt seem to pull that much, maybe a bit to the right, but road around here are not the best. The issue I have is the thrust angle. The rear toe says -.20 on the left and .16 on the right, and gives me a thrust angle of -.18.
They claim it is not fixable. I know the rear is not adjustable, but they could counteract it with some toe adjustment correct? The spec is -.15 to .15, so its only .3 adjustment. I looked under the car and the trailing arms look to be in good shape. thats the only thing I could think of that would throw off the toe. anyone else? could he just not of bounced the car and it was giving a false reading?
06-23-2011, 04:14 PM
#2
Alot of solid axle cars can show slight variation in rear toe. Even my own car does that, i cant explain it. Whats even more strange is when you see negative camber on one side of a solid axle and positive camber on the other end.
Typically when a 4 wheel alignment is done, the front toe IS set in reference to the thrust angle. This isnt something you would see on a printout though, and also think about how the only way to center the steering wheel is literally by EYE. So it can easily be messed up. I'd just take it back and tell them to do it again til its right.
Typically when a 4 wheel alignment is done, the front toe IS set in reference to the thrust angle. This isnt something you would see on a printout though, and also think about how the only way to center the steering wheel is literally by EYE. So it can easily be messed up. I'd just take it back and tell them to do it again til its right.
06-23-2011, 06:18 PM
#3
I just find it odd that the toe isnt off the same amount. if its a straight axle, the negative on one side should be the same number only a positive on the other right? I guess in reality its not that far off at .04 degrees difference, but it seems like the rear is a good bit cocked at .20 degrees angle. Even though the rears dont wear funny and it didnt pull to one side.
I read the specs for setting alignment on the car, and it said it needs a full tank of gas. so i filled it up and they are supposed to correct the steering wheel tomorrow.
I read the specs for setting alignment on the car, and it said it needs a full tank of gas. so i filled it up and they are supposed to correct the steering wheel tomorrow.
06-24-2011, 09:09 AM
#4
I just find it odd that the toe isnt off the same amount. if its a straight axle, the negative on one side should be the same number only a positive on the other right? I guess in reality its not that far off at .04 degrees difference, but it seems like the rear is a good bit cocked at .20 degrees angle. Even though the rears dont wear funny and it didnt pull to one side.
The thrust angle is used as a reference for the alignment so rear toe/thrust angle (on a solid axle) wont make the car pull or make the tires wear. It could make the car track funny but i doubt you'd be able to tell while driving. Total toe in the rear could affect tire wear but its static on solid axles.
06-24-2011, 02:33 PM
#5
I just find it odd that the toe isnt off the same amount. if its a straight axle, the negative on one side should be the same number only a positive on the other right? I guess in reality its not that far off at .04 degrees difference, but it seems like the rear is a good bit cocked at .20 degrees angle. Even though the rears dont wear funny and it didnt pull to one side.
I read the specs for setting alignment on the car, and it said it needs a full tank of gas. so i filled it up and they are supposed to correct the steering wheel tomorrow.
I read the specs for setting alignment on the car, and it said it needs a full tank of gas. so i filled it up and they are supposed to correct the steering wheel tomorrow.
I know what you mean about the toe out on one side, should be the same as the toe in on the other side, but I'd say any variation could be attributed to how the "targets" are clamped on the wheels of the car.
I've always aligned my cars with a half tank of gas....
06-24-2011, 07:39 PM
#6
well, had the wife take it back in this morning to fix the steering wheel alignment. They gave me the before and after specs this time. Toe on the front went from .04 left and
.05 right to .32 left and -.45 right. Would adding a few gallons of gas actually effect it that much? the caster and camber stayed pretty much the same.
after they adjusted it, it now has -.20 thrust angle. The car now drives with the steering wheel straight up and down. It may track slightly to the right, but its hard for these cars to track straight with even slight grooves in the road.
I'm gonna chalk up my issues with firestone yesterday to newbie errors. The wife told me the guy asked her yesterday for the locking lug nut key. She asked him why he would need it cause the tires dont come off for an alignment. He said they just might need it to make adjustments.
.05 right to .32 left and -.45 right. Would adding a few gallons of gas actually effect it that much? the caster and camber stayed pretty much the same.
after they adjusted it, it now has -.20 thrust angle. The car now drives with the steering wheel straight up and down. It may track slightly to the right, but its hard for these cars to track straight with even slight grooves in the road.
I'm gonna chalk up my issues with firestone yesterday to newbie errors. The wife told me the guy asked her yesterday for the locking lug nut key. She asked him why he would need it cause the tires dont come off for an alignment. He said they just might need it to make adjustments.
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06-25-2011, 02:57 PM
#9
door jam says 30psi, but I find that retarded. Thats asking for a blow out. Ask Ford, they figured that out when they recommended 26 psi in their firestone tires... Plus, you increase tire psi with speeds over 100 mph, so on a car good for 160, why would you only have 30psi to start with. the tires say 44 psi max. at around 34-36 psi, the tires look properly inflated to me.
06-26-2011, 04:55 PM
#13
32 in front 28-30 in the rear. I have 315s on the rear and that pressure has been wearing them pretty evenly so far. Sometimes i raise the front a little to cut down on edge wear, doesn't have as much effect as alignment though.
Remember pressure rises with temperature, so the closer you push that tire to its limit (44psi cold), with speed it will be even closer or even surpass that limit and THAT is putting you at risk of a blowout.
I'm definitely not saying do top speed runs at 28 psi though. The pressures you run are probably good for speed but could possibly cause unnecessay wear on the tires under normal driving.
Remember pressure rises with temperature, so the closer you push that tire to its limit (44psi cold), with speed it will be even closer or even surpass that limit and THAT is putting you at risk of a blowout.
I'm definitely not saying do top speed runs at 28 psi though. The pressures you run are probably good for speed but could possibly cause unnecessay wear on the tires under normal driving.
Last edited by spy2520; 06-26-2011 at 05:00 PM.
06-26-2011, 05:08 PM
#14
Im guessing that under normal driving conditions, I wont exceed 40 psi when warm. I get this from the TPS on my Silverado. I set all the tires at 36 psi in it and I havent seen it exceed 40 psi after driving, even on 800 mile plus trips. At this point, I'm the same as you. I havent seen any abnormal tire wear from doing so I will keep them at this pressure until something happens.
06-29-2011, 10:50 PM
#15
To shed a little light on this. While aligning my '02 SS, we started with the rear. It showed off by .1 degree. Not knowing what to expect, we adjusted the panhard bar. It looked right by eye, but sure enough, a few turns and it was straight on. Your guys with adjustable PHB's need to know that although it seems like a rudimentary rear centering adjustment, it is definitely more than a "driveway" adjustment. Anytime you do an alignment, be sure it's 4-wheel!
