Wheel alignment specs, .. please

Thumper3 · #1 10-23-2009, 03:03 AM

Have 2004 FX4 S-cab, 145" WB, stock suspension and wheels. Current tires are GY Wrangler SilentArmor, 275/70R17 and are 1.1 in. taller than OEM. Need to do front wheel Toe-in alignment check and possible adjust. Would someone provide the correct toe-in spec range as a distance measurement (instead of angle). I will be using an old bubble gauge and pointer stick alignment set. Also please note if the provided distance is for total toe or per side. Thanks.

Had tires put on yesterday. (Sorry Wandell, the 285 D's were too stiff / too wide / and too $$ for my use. Went with the 275 C's). Tires took 2 hrs as tireman left for dinner with all wheels off and one new tire mounted. Then he got in hurry with the impact and didn't want to hand torque for alum wheels. Next he tried to take out their overhead door with my ladder rack (rack OK - door off track). While I was having them remove a $160 tire protection policy I hadn't asked for from my invoice, their alignment guy announced my alignment was way out. I checked and the left front tire was inflated 6 lb over the right side and both rears were 2 and 4 lb lower than the fronts. All were considerably under-inflated. I kept the tires but passed on the rest. Now I want to do at least a pre-shop check and maybe the whole alignment (camber/caster both were supposedly good and equal each side). Old tires showed no wear pattern problems. Note: I use two 3/16" thick, foot square steel plates with a shot of grease between them (a pair under each front tire) for glider plates to do alignments - on a level floor.

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Patman03SprCrw · #2 10-28-2009, 12:01 PM

Looking for frnt end align specs

dunno if those are accurate or not

Thumper3 · #3 10-28-2009, 03:01 PM

Thanks Patman. I think those are accurate angles. Did some more reading. Anyone have the math to verify my conversion of the toe-in angle to a length (inch/fraction) measurement?

a=b*tanA where a= the amount of toe-in, b=radius of tire, and A= toe angle. as:

a=16.1 * tan 0.07 or abt 16.1 * 0.00203 or .033 inch (1/30 inch) from center to tread or 1/15" difference from rear to front of tire?? (per side)

Patman03SprCrw · #4 10-28-2009, 09:02 PM

are you trying to attempt doing your own alignment in your driveway?

Thumper3 · #5 10-29-2009, 03:59 AM

No. In my self-built 28 x 32 clear span shop/garage (two story). You sound a bit doubtful

of outcome. First off, I want to thank you for your reply. It had the info that I couldn't find, to get me started. BUT...
I did do 7 yrs as flat-rate auto body/frame tech at a dealership (back when it was mostly bubble gauges and tape measures -- we had to pull to within less than 1/2 of the factory tolerance before the foreman would release to the wheel alignment tech). Still have same tools. I worked on a 50/50 rate split with the shop. The shop charged customers $8.25/hr labor and was considered a more expensive shop for the city at the time. Also drove long-haul reefer's and was a manager (8 yrs) at an auto and motorcycle dealer. Then 25 yrs as civilian Senior Test Director (testing and redesigning Material Handling & Construction Equipment and Automotive testing) at Combat Systems Test Activity, US Army Aberdeen Proving Ground. Been retired awhile now and just needed some specs and some good help

(which you provided) to kick start my senile memory bank. This is my first 4WD truck, though.

Apology for the rant Patman, bad day & needed to vent.

Besides, per first post I said I wanted to pre-check (so I know where it's really now set, before I took it to a shop maybe as rip as the previous one) and possible adjust

Patman03SprCrw · #6 10-29-2009, 10:15 AM

well if you take it somewhere to get a free alignment check and they give you a print out, the specs are usually on the print out as well.

I do sound doubtful, but I work on a fairly modern lazer alignment machine on Land Rovers with full Air suspension setups, and even then its hard to get them perfect.