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#2456834 - 02/24/18 03:23 PM Front End Tire Wear
MarkM Offline
Worthy

Registered: 01/13/05
Posts: 2249
Loc: USA, MI
I've had an issue for some time now with the front end of my car wearing the outsides of the tires. I've had it aligned twice in the last two years, yet the wearing is getting worse. From the printout I got comparing the two previous years camber and caster have stayed the same, so I think it's more a less a problem of not being aligned to a spec that doesn't cause tire wear. Problem is, I have no idea what values to ask for and it's obvious whatever factory spec is it isn't working.

Need some advice before replacing the front tires again... Thanks guys...





Edited by MarkM (02/24/18 06:35 PM)
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#2456861 - 02/24/18 04:01 PM Re: Front End Tire Wear [Re: MarkM]
BigBlockMopar Offline
master

Registered: 01/22/03
Posts: 3387
Loc: The Netherlands
I think for one thing, since camber/caster are exactly the same, the shopmonkey didn't touch anything but the tie rods on the second "alignment".

Then, camber should be slightly negative. Certainly not positive, that's for old cars running diagonal tires.

I would also be looking at worn/soft bushings like idler arm, strut rods or in the upper/lower control arms.
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#2456942 - 02/24/18 06:15 PM Re: Front End Tire Wear [Re: MarkM]
Bob J Offline
member

Registered: 11/16/16
Posts: 189
Loc: Colorado
After you check for worn parts find a race shop to do the alignment. You will pay more but they will and set it correctly.
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#2456943 - 02/24/18 06:17 PM Re: Front End Tire Wear [Re: MarkM]
Mattax Offline
super stock

Registered: 02/28/10
Posts: 1111
Loc: Phila. Pa.
What do the printouts show?

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#2456948 - 02/24/18 06:39 PM Re: Front End Tire Wear [Re: MarkM]
MarkM Offline
Worthy

Registered: 01/13/05
Posts: 2249
Loc: USA, MI
Sorry, for some reason the image of the printout didn't embed properly in the original message - I just fixed it.

All the parts on the front end are new. Moog bushings/joints/tie rods & sleeves/etc. Firm Feel T bars, and Firm Feel upper control arms.

It was a race shop that both alignments.
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#2456973 - 02/24/18 07:29 PM Re: Front End Tire Wear [Re: MarkM]
ruderunner Offline


Registered: 12/18/14
Posts: 1967
Loc: ohio
Idler arm good? No slop in the torsion bar bushings?

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#2457005 - 02/24/18 08:08 PM Re: Front End Tire Wear [Re: MarkM]
GoodysGotaCuda Offline
5.7L Hemi, 6spd

Registered: 11/23/04
Posts: 24347
Loc: Texas
I'd question the equipment was installed on the car properly. It doesn't take much toe to burn off rubber.

I would be running a tape measure to see if the toe is in the ballpark
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#2457011 - 02/24/18 08:15 PM Re: Front End Tire Wear [Re: BigBlockMopar]
autoxcuda Offline
Too Many Posts

Registered: 01/20/03
Posts: 25941
Loc: So Cal
Originally Posted By BigBlockMopar
I think for one thing, since camber/caster are exactly the same, the shopmonkey didn't touch anything but the tie rods on the second "alignment".

Then, camber should be slightly negative. Certainly not positive, that's for old cars running diagonal tires.

I would also be looking at worn/soft bushings like idler arm, strut rods or in the upper/lower control arms.


It sure seems like a "Toe and Go" alignment. Very few newer cars have camber and caster adjustments.

.28 degrees total toe on a 25.5" diameter tire is 1/8" toe.


I would suggest on a car that gets a good amount of street miles:

.5-.25 negative camber.

3.5 to 2.5 positive caster

.120 degrees total toe-in ( 3/32")


you can easily gain positive caster and negative camber, if there is inward adjustments on the rear cam eccentrics on BOTH sides of the car.

FYI .075 deg total toe on a 25.5" tire is 1/16" toe in.


Convert Toe Angle to Inches:

https://robrobinette.com/ConvertToeDegreesToInches.htm
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#2457072 - 02/24/18 09:26 PM Re: Front End Tire Wear [Re: MarkM]
myduster360 Offline
enthusiast

Registered: 01/20/03
Posts: 332
Loc: central IL
Excessive Toe-in is causing the outside edges to wear, not the Camber nor Caster.

That .6 degrees is WAY OUT, nearly 2x.

.28 degrees total Toe-in is perfectly fine now but what was the Toe in the previous years alignments?


Edited by myduster360 (02/25/18 01:11 PM)
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#2457293 - 02/25/18 10:54 AM Re: Front End Tire Wear [Re: MarkM]
TC@HP2 Offline
master

Registered: 01/23/03
Posts: 4862
Loc: Pikes Peak Country
I'd agree with the previous replies on toe. The fact that they are a "race" shop and didn't suggest better specs to you would make my suspicious of them. If they are giving you free or low cost adjustments to get it back where it should be, then you might stick with them, otherwise, I'd look for a new place.

Ditch the 5th Avenue specs for '05 Mustang GT specs.

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#2457328 - 02/25/18 12:13 PM Re: Front End Tire Wear [Re: MarkM]
autoxcuda Offline
Too Many Posts

Registered: 01/20/03
Posts: 25941
Loc: So Cal
I see .4 more positive caster on left side. Ok that may be for road crown.

But why not then run .8 negative camber on left side to equal things up? Is the .8 negative camber on right side also for road crown?

Is the tire pictured above the left front?
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#2457368 - 02/25/18 01:35 PM Re: Front End Tire Wear [Re: autoxcuda]
Mattax Offline
super stock

Registered: 02/28/10
Posts: 1111
Loc: Phila. Pa.
Originally Posted By autoxcuda
It sure seems like a "Toe and Go" alignment.

Mark, That's what you're looking at there. They only adjusted the toe. Sorry but thats what happened.

That camber is out of spec even for the original bias & cross ply tires.
eg from 1968 Plymouth Service Manual.
Left: +0.25 to +0.75, Right: 0 to +0.5 degrees

With modern radial tires - especially performance tires - they will want some negative camber. (Competition tires all have recommend range you can get from the manufacturer.) If you have nothing else to go by, based on tire wear with +.8 on the one side, and assuming radial construction, go for -.5 camber both sides as a starting point.

Alignment changes must be done in sequence. The factory service manuals lay this out very well. This reduces the number of iterations to get everything in spec.
1. Adjust ride height.
2. Adjust Camber
3. Adjust Caster
4. Adjust Toe


Edited by Mattax (02/25/18 01:41 PM)

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#2457386 - 02/25/18 02:26 PM Re: Front End Tire Wear [Re: Mattax]
autoxcuda Offline
Too Many Posts

Registered: 01/20/03
Posts: 25941
Loc: So Cal
Originally Posted By Mattax
Originally Posted By autoxcuda
It sure seems like a "Toe and Go" alignment.

Mark, That's what you're looking at there. They only adjusted the toe. Sorry but thats what happened.

That camber is out of spec even for the original bias & cross ply tires.
eg from 1968 Plymouth Service Manual.
Left: +0.25 to +0.75, Right: 0 to +0.5 degrees

With modern radial tires - especially performance tires - they will want some negative camber. (Competition tires all have recommend range you can get from the manufacturer.) If you have nothing else to go by, based on tire wear with +.8 on the one side, and assuming radial construction, go for -.5 camber both sides as a starting point.

Alignment changes must be done in sequence. The factory service manuals lay this out very well. This reduces the number of iterations to get everything in spec.
1. Adjust ride height.
2. Adjust Camber
3. Adjust Caster
4. Adjust Toe


Oh cr@p !

I didn't notice it had POSITIVE .8 degrees of camber.

That BS. Have them fix that at the very least.


Edited by autoxcuda (02/25/18 06:46 PM)
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#2457395 - 02/25/18 02:49 PM Re: Front End Tire Wear [Re: MarkM]
Pacnorthcuda Offline
I Live Here

Registered: 11/19/07
Posts: 19085
Loc: Kirkland, Washington
I think the shop was lazy and their system isn't working with correct numbers. No way is that .8 positive camber on the right front "in spec"
I would go back and demand .5 Negative.

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#2458622 - 02/27/18 08:23 PM Re: Front End Tire Wear [Re: Pacnorthcuda]
ahy Offline
master

Registered: 01/22/07
Posts: 7625
Loc: IN
Toe looks OK. Agree it needs negative camber, especially with radials. Positive camber will wear the outsides. You need between .5 and .75 degree negative camber and as much positive caster as you can get up to 5 degrees.

Also, you really need to tell the shop what you want. A good and friendly shop will try to dial it in as requested. At least that is my experience. Otherwise, most do not know what to do with a classic T bar car.

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