2-wheel vs. 4-wheel Alignment?

I was checking around some shops for a front end alignment & one of them suggested I should always get a 4 wheel alignment instead. He said a 2-wheel alignment adjusts the front wheels with respect to the vehicle centerline, but a 4-wheel alignment ensures the front wheels match the orientation of the rears & makes sure the rears are in correct proportion to the centerline (even on vehicles without adjustable rears).

Any thoughts on all of this? Should I be going for the 2-wheel or the 4-wheel alignment??

I guess it would have to do with the vehicle. An F-body would only require a TWO wheel or Front End Alignment as you have a solid axle and there are no factory alignment adjustments ( You can do things w/shims and Adjustable panhard rods etc). He is correct in that a Front End Alignment only aligns the front tires to each other, what I typically sell my customers ( I am a service advisor/writer ) is a Thrust Angle Alignment, that is a Front End Alignment + having the tires set to the travel path of the car... If you have ever seen a car/truck go down the road all cattywampus err dogtracking ( sits kinda skewed or angled ) that is typically from only having a TWO / Front end alignment done. I don't charge more for a THRUST angle job then a TWO wheel. If anyone tries to tell you its more labor... Tell em to pound sand..All the labor is in setting up the heads on the alignment rack really..
Or print this out and show it to em !! I work for Goodyear and do HUNDREDS of alignments a year.
Doug ~

PS : Front wheel drive cars or cars with IRS ( Independant Rear Suspension ... think Vette or Cobra.. Should have four wheel alignments {I charge ten dollars more for a Four wheel than I do a Two wheel} 59.99/69.99 altho when I set a Vette up for a Road Course it's 129.99<cause its a beeyatch>

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Originally Posted by jcws6

I was checking around some shops for a front end alignment & one of them suggested I should always get a 4 wheel alignment instead. He said a 2-wheel alignment adjusts the front wheels with respect to the vehicle centerline, but a 4-wheel alignment ensures the front wheels match the orientation of the rears & makes sure the rears are in correct proportion to the centerline (even on vehicles without adjustable rears).

Any thoughts on all of this? Should I be going for the 2-wheel or the 4-wheel alignment??

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the guy is a little confused over what two wheel (thrust angle) and a four wheel alignments are. for the most part 01T is correct.

a two wheel/thrust angle alignment means only the front is adjustable.

a four wheel alignment means all four wheels are adjustable.


i own an alignment/suspension shop.

a two wheel, front end, and thrust angle alignment are the same thing. both reference off the vehicle centerline and use the rear thrust angle to center the steering wheel. without having the rear sensors on, you cannot measure caster and find the vehicle centerline. with only hooking up the front sensors, you can only adjust camber and toe. to measure caster, the sensors need to complete the 'box'. they need to know where the vehicle centerline is, so when you take a caster measurement, it can find the 10* swing left and right to make the measurements.

i charge the same, whether it's a thrust angle, four wheel, or anything road racing/autocrossing. doing a 'special' road racing alignment is no different than doing a standard thrust angle or four wheel alignment. you still have to set all angles to desired specs, whether stock or modified. you just have to spend a little more time getting the vehicle set to the specs the autocrosser/road racer is asking for. not just getting into the allowed range.

i work for myself and actually do 75-100 alignments a month.

Any time you see a vehicle going or coming down or up the road & it appears cattywumpus its more than an alignment problem.That vehicle has frame damage & probably suspension damage !
All front wheel drive vehicles require 4-wheel alignment & most all-wheel drive & most units with front & rear independent suspinsion.:drunk:

Thanks for the information, guys (cattywampus??). I'm glad there are actual alignment techs here who can provide real info. Looks like I'll be getting a 2-wheel "thrust angle" alignment. I have 1 more question for you guys: Just out of curiosity, what's a generally acceptable thrust angle range? I know 0 degrees is perfect, but what's the maximum +/- number, before you recommend rear end repairs?

.25* thrust angle is only about 3/16" turned. so, if was around 1*, about 7/8", then it would be time to consider adjustable trailing arms and panhard rod. to be that far off, usually means worn trailing arm bushings, or accident.

Don't forget how important the correct pinion angle is , especially with a lowered vehicle. This is the cause of several rear axle & u-joint breakdowns .

I have some experience (and still learning ) with alignments,as a matter of fact only 10 hours ago ( on Sept 1 st 07 @ 12 noon) I retaired @ 67 years and 11 months, from this profession, after 30 years 8 months same perfession,same shop, on a differant note being this age with this experience does not mean I know it all or more than the others here, it only means I am older and have some experience,on my car everthing is adjustable,I run thrust angle @ + .02 to + 06 , none -,my car lounches stright as a arrow with this setting , but cars are differant.
I have some info about alignments on my site if any one would like to visit
after connecting to opening page click on the "emblem" in center of page then proceede to 2-4 pages by "enter" or "contune"
good luck, Johnny
http://kickme.to/jgruggles