Technical Wheel alignment/ tracking

[WitleyPanda]

Having fun with abnormal wear on front of a 4x4. Anyone have any knowledge to share on the correct toe-in ( 1mm +/-1 or as angle 9") and critically of setting. Or input on methods and which commercial kit has correct database for these setting?

 

[vexorg]

What kind of abnormal wear?

Has the car ever been in an accident?

 

[WitleyPanda]

What kind of abnormal wear?

Has the car ever been in an accident?

Wear on the inside 1/3. No accident/s coil springs broke, but wear post dates replacement. No wear in any of suspension set-up , checked by two third parties whom I trust and by self. initial laser alignment within tolerance. Checked also at home with "Trackace" and circa 10'. Will post photos later in week.

 

[bugsymike]

This is from my 2012 AutoData manual if any help. I have a 1960s Dunlop Wheel Alignment Gauge which I rely on.
Re wear on inside edge of tyre, if tracking is OK it can be caused by soft wishbone bushes or springs causing the wheel to settle slightly out at the bottom, in effect like negative camber.
There are various cheap camber gauges available which may prove or disprove this.
I did used to own a Dunlop Castor and Camber Gauge also, but as I didn't use it very often like an idiot I sold it!

 

[WitleyPanda]

This is from my 2012 AutoData manual if any help. I have a 1960s Dunlop Wheel Alignment Gauge which I rely on.
Re wear on inside edge of tyre, if tracking is OK it can be caused by soft wishbone bushes or springs causing the wheel to settle slightly out at the bottom, in effect like negative camber.
There are various cheap camber gauges available which may prove or disprove this.
I did used to own a Dunlop Castor and Camber Gauge also, but as I didn't use it very often like an idiot I sold it!

Thanks, most grateful. Data obviously for pre 2012 and for 2 wheel drive, which same as i have found on internet for late 2 wheel. Car MOTed last wheel and specifically asked tester if he could feel any movement on wishbone bushes, negative. I have acquired a camber/caster gauge, but live on side of a hill so have not checked that yet.

 

[WitleyPanda]

Penny dropped !!! All the documentation refers to toe-in, but for a 4x4 it is a negative value, i.e. toe-out !!! Thread is M12 x1.5 mm pitch so should be able to ratio the length of steering arm to half rim diameter and calculate.

 

[bugsymike]

Penny dropped !!! All the documentation refers to toe-in, but for a 4x4 it is a negative value, i.e. toe-out !!! Thread is M12 x1.5 mm pitch so should be able to ratio the length of steering arm to half rim diameter and calculate.

Assuming the camber side is OK , generally the more "toe out" the more the tyre will wear on the inside edge and the more "toe in" the more wear on the outside edge of the tyre.
In the old day with mostly rear wheel drive cars tended to have "toe in" as the rear wheels pushing the car forward had the affect of spreading the front wheels, conversely front wheel drive cars have the affect of pulling the wheels together so they usually start with "toe out" to compensate in basic terms.
I haven't looked into how 4x4 effects that.

 

[WitleyPanda]

generally the more "toe out" the more the tyre will wear on the inside edge

Hence my resistance to toe out further to reduce inside wear ?

 

[bugsymike]

Hence my resistance to toe out further to reduce inside wear ?

Have you got a camber reading yet?