How is toe in measured?
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Elder User
Joined: May 2004
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From: Northwest Florida
How is toe in measured?
I've seen threads that declare toe in for our trucks should be .1 +or- .025 (I think). What does the .1 represent, degrees? Can anybody translate that to inches or mm's?
I measured mine using the taut fishing line method. It showed the front center line of each tire to be 5/16" inward from the back. Compared to the other tire, that would be 5/8" closer in the front. Does this seem like excessive toe in? seems to me it should be less.
My front tires have worn excessively more on the outside of the tread than the inside. I know it could also be too much positive camber, and I'm going to have it checked on a machine, but trying to learn in the mean time.
Thanks in advance.
I measured mine using the taut fishing line method. It showed the front center line of each tire to be 5/16" inward from the back. Compared to the other tire, that would be 5/8" closer in the front. Does this seem like excessive toe in? seems to me it should be less.
My front tires have worn excessively more on the outside of the tread than the inside. I know it could also be too much positive camber, and I'm going to have it checked on a machine, but trying to learn in the mean time.
Thanks in advance.
Posting Guru
Joined: Apr 2008
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From: Albemarle, NC
.1 represents one tenth of a degree. .625 that you have is excessive IMO. You need to get it on a good alignment machine so you can check the toe, camber and caster. take it somwhere that has state of the art equipment that can physically show you the screen or a print out of before and after measurments. Too many people like to "set the toe and let it go" or "if its green its good" The SD trucks have a WIDE range of what is considered "spec" Example, you could have 4.0* posative caster on the RH side, and 2.0* on the LH side and still be within "spec" but it will drive like crap.
Posting Guru
Joined: Oct 2009
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From: Rogue River, Oregon
Not exactly, toe-in is measured in inches, camber and caster are measured in degrees. That means the centerline at the front of the your tires should be (for example) 1/8" closer then the centerline at the rear. Too little toe-in causes wandering, while too much causes excessive tire-wear.
Posting Guru
Joined: Apr 2008
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From: Albemarle, NC
Not exactly, toe-in is measured in inches, camber and caster are measured in degrees. That means the centerline at the front of the your tires should be (for example) 1/8" closer then the centerline at the rear. Too little toe-in causes wandering, while too much causes excessive tire-wear.
Posting Guru
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From: Albemarle, NC
Here are the specs right from the ford workshop manual
Alignment Specifications — F-250 and F-350, 4x4
.
Caster @ Curb Ride Height 3.5° ± 2° 3.5° ± 2° 0° ± 1°
Camber @ Curb Ride Height 0.25° ± 1° 0.25° ± 1° 0° ± 1°
Toe @ Curb Ride Height (Positive Value Is Toe-In, Negative Value Is Toe-Out) — — 0.03° ± 0.25°
Steering Axis Inclination (SAI) @ Full Load — — 8.5°
Included Angle @ Full Load — — 8.5°
Alignment Specifications — F-250 and F-350, 4x4
.
Caster @ Curb Ride Height 3.5° ± 2° 3.5° ± 2° 0° ± 1°
Camber @ Curb Ride Height 0.25° ± 1° 0.25° ± 1° 0° ± 1°
Toe @ Curb Ride Height (Positive Value Is Toe-In, Negative Value Is Toe-Out) — — 0.03° ± 0.25°
Steering Axis Inclination (SAI) @ Full Load — — 8.5°
Included Angle @ Full Load — — 8.5°
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Elder User
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From: Northwest Florida
Toe @ Curb Ride Height (Positive Value Is Toe-In, Negative Value Is Toe-Out) — — 0.03° ± 0.25°
Here's what confuses me; the tolerance number (.25) is bigger than the spec number (.03). And is the .03 a negative value? The way it reads, you'd be in specs with anything from negative .22 to positive .28 if the .03 is positive.
Here's what confuses me; the tolerance number (.25) is bigger than the spec number (.03). And is the .03 a negative value? The way it reads, you'd be in specs with anything from negative .22 to positive .28 if the .03 is positive.
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Posting Guru
Joined: Apr 2008
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From: Albemarle, NC
Yes, like I posted above, the SD has a very WIDE range that is considered "spec" .03 is optimum, but anything within .25 of that is considered acceptable. .03 is posative toe.
NOTE: Dont use those specs I listed, they are just a generic spec I found online, no idea what year they are for.
NOTE: Dont use those specs I listed, they are just a generic spec I found online, no idea what year they are for.
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Posting Guru
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From: Rogue River, Oregon
While I don't claim to know everything, I think 35 years of building hot rods and tuning race cars at least counts for something. The problem with using degrees as a unit of measurement (as some "technicians" do these days) is that it doesn't take into account tire diameter. Set your toe-in at (for example) 1 degree with 30" tires, then swap on some 38" tires a year later and you have effectively increased your toe-in, right? Old methods do not mean antiquated, do they? You're right about things being "within spec" yet being wrong, and far too many guys at alignment shops just "go by the book" and wonder why the vehicle doesn't drive right.
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