FRAMING JOHN DELOREAN - ON VOD www.framingjohndeloreanfilm.com
Page 1 of 4 1 2 3 ... LastLast
Results 1 to 10 of 32

Thread: Demystifying toe alignment specifications

  1. #1
    '82 T3 FABombjoy's Avatar
    Join Date:  May 2011

    Location:  Lansing, MI

    Posts:    1,090

    My VIN:    10270

    Demystifying toe alignment specifications

    I'm finishing up a new suspension and I'm having some trouble wrapping my head around the alignment numbers as given in the bulletin.
    At first glance it seems straightforward: 3mm toe-in per wheel.

    I have a strings alignment setup and different wheels with tire diameters. Its easier to convert to toe angle rather than mm or inches.

    Converting a static measurement like 3mm requires a fixed diameter measurement to find the angle. The question is, what is that diameter?
    -Tire diameter
    -Wheel diameter
    -A fixed industry standard, such as 28" described in the SmartStrings alignment manual


    Here's where it gets muddled
    -If related to a fixed standard, both ends of the car have the same angle in degrees.
    -If related to tire/wheel diameter, the rear spec is actually less toe in than the front due to the larger diameter. This would place the rear thrust angle further forward.
    -In either case, neither matches the degrees value in figure 4 given in the bulletin

    ST-34-1/82 specifies 3mm or 0.12". There is a chart of fractional inches to degrees.
    1/8" (.125") is about .26 degrees, so this chart indicates a hair under .26 degrees

    Referencing alignment data posted here from a Hunter alignment machine:
    https://timemachine16606.tumblr.com/...heel-alignment
    This machine specifies 0 degrees 14 minutes, or 0.233 decimal degrees.

    https://www.16908.info/?m=200805
    This machine specifies 0.24 degrees

    I pulled an old alignment of my own from 2016, also Hunter, also specifying .24 degrees.

    Based on the above data & calculators, here's how things work out.
    Diameter to degrees using calculator here: https://robrobinette.com/ConvertToeInchesToDegrees.htm


    So uh... does anyone have real-world experience with any of these numbers, or can shed some light on the discrepancies? Or maybe the math is off somewhere?
    Luke S :: 10270 :: 82 Grey 5-Speed :: Single Watercooled T3 .60/.48 :: Borla Exhaust :: MSD Ignition :: MS3X Fully SFI Odd-fire EFI :: DevilsOwn Methanol Injection

  2. #2
    LS Swapper Josh's Avatar
    Join Date:  Mar 2013

    Location:  SK, Canada

    Posts:    2,344

    My VIN:    11408

    Club(s):   (ADOA)

    you are my hero

    Supercharged 5.3L LS4 + Porsche 6spd
    LS Swap Parts:
    http://lsdelorean.com

  3. #3
    '82 T3 FABombjoy's Avatar
    Join Date:  May 2011

    Location:  Lansing, MI

    Posts:    1,090

    My VIN:    10270

    This is what I get for checking the service manual
    Luke S :: 10270 :: 82 Grey 5-Speed :: Single Watercooled T3 .60/.48 :: Borla Exhaust :: MSD Ignition :: MS3X Fully SFI Odd-fire EFI :: DevilsOwn Methanol Injection

  4. #4
    Matt Drive Stainless's Avatar
    Join Date:  Mar 2016

    Location:  Washington D.C.

    Posts:    566

    3mm is 0.11811", which, when multiplying by 2 gives you 0.23622" Total Toe, which is what the site (https://robrobinette.com/ConvertToeInchesToDegrees.htm) requests in the first box. It looks like you may have entered toe for one wheel instead?

    For the front (diameter 23.2"), I calculate 0.2916948901253558 degrees for each wheel.
    For the rear (diameter 26.1"), I calculate 0.2592834064593833 degrees for each wheel.

    Thus for a total toe of 0.23622" (roughly 1/4"), the conversion table in ST-34-1/82 states, 1/4" = 0.51 degrees, which is pretty close to 0.259*2, so I consider this confirmation that my calculations above are correct.

    As a side note, I believe the conversion table on page 4 of ST-34-1/82 could be more accurately labeled as applicable to the rear toe measurement only.
    Last edited by Drive Stainless; 07-01-2021 at 10:03 PM.

  5. #5
    Senior Member
    Join Date:  May 2011

    Location:  Northern NJ

    Posts:    8,100

    My VIN:    10757 1st place Concourse 1998

    While it is possible to do an alignment with a ruler and string, it is one of the jobs best done by someone with some experience and a modern 4 wheel alignment rack. For $80-$100 and an hour of time they can do it a lot faster (and probably more accurately) than you at home. Some jobs just aren't worth trying to do yourself like mounting and balancing tires, glass work, and alignments. Get it wrong and the car can be hard to control, especially in a panic situation, and you wear out tires quickly. Find the shop in your area that does police cars and ambulances, they usually do the best work. Once done an alignment will hold unless you have an accident or replace suspension parts (a long time). Signs that you need an alignment and/or you have worn or bent parts;
    Steering wheel not centered when going straight on a flat road
    Car tends to wander (doesn't want to go or stay straight)
    Car tends to go to one side when not braking (can also be a dragging caliper)
    Tires wearing unevenly (first check air pressure)
    Steering wheel does not want to return to center by itself
    These symptoms can also be caused by a bad tire. Any good shop will check tires and suspension BEFORE trying to do an alignment. No point doing an alignment on a car with worn or bent parts or bad tires, it won't work. To prepare a car for an alignment you can:
    Check for any worn, loose, bent parts
    1/2 tank of gas
    Check the tire pressures
    Replace any old or worn tires
    Remove all of the "junk" in the car.
    Lubricate the suspension
    Bring the alignment specs. If the machine doesn't have them already the tech can enter them manually.
    Ideally you should bring a set of shims for the rear TAB's and the proper torque specs. Remove the shields. The only adjustments are the front toe, centering the steering wheel and the toe on each rear wheel. All of the other specs are to be checked and if not within spec something is worn, bent or broken. If the ride height has been changed, it affects all of the other specs.
    David Teitelbaum

  6. #6
    '82 T3 FABombjoy's Avatar
    Join Date:  May 2011

    Location:  Lansing, MI

    Posts:    1,090

    My VIN:    10270

    Quote Originally Posted by Drive Stainless View Post
    3mm is 0.11811", which, when multiplying by 2 gives you 0.23622" Total Toe, which is what the site (https://robrobinette.com/ConvertToeInchesToDegrees.htm) requests in the first box.
    Oh, you're right, I missed that the site specifically called out total toe, d'oh!
    That lines things up more closely to defacto 0.245 degrees which is looking like the number to shoot for.

    Quote Originally Posted by David T View Post
    AI GENERATED OUTPUT
    Too late, I'm insistent on using basic arithmetic to learn and enjoy the process even if it doesn't use lasers PEW PEW
    Funny in all that text you didn't even address the original question.
    Also I love all the junk in the car HOW DARE YOU
    Luke S :: 10270 :: 82 Grey 5-Speed :: Single Watercooled T3 .60/.48 :: Borla Exhaust :: MSD Ignition :: MS3X Fully SFI Odd-fire EFI :: DevilsOwn Methanol Injection

  7. #7
    Senior Member
    Join Date:  May 2011

    Location:  Northern NJ

    Posts:    8,100

    My VIN:    10757 1st place Concourse 1998

    Enjoy the process. What I meant when I mentioned "junk" is all of the stuff you accumulate in the car. If you take the weight of the car, fill the gas tank,add the weight of 2 people and then look at the max, there isn't much left for anything. You can overgross the car very easily. Besides, that weight changes the ride height and that affects all of the specs. To really do an alignment you take measurements at at least several ride heights and make a chart. Then you can see how things change over the suspension travel. You use sandbags to simulate a driver. You need bearing plates so the suspension can "settle out" because the wheels move in and out and tilt as the ride height changes. "Back-in-the-day" all we had were bubble levels and got it close. Today we can split degrees with lasers. The better your alignment the better the tire wear and gas mileage. This whole topic can take up a collage course. I recommend you find a good book on suspension tuning. There are also a lot of youtube videos on this. After you finish you will have a much better appreciation of the science of alignments.
    David Teitelbaum

  8. #8
    Senior Member
    Join Date:  Nov 2013

    Location:  NYS

    Posts:    2,511

    My VIN:    4519

    ....I CAN'T be the only one who sees it -LMAO.

  9. #9
    Motors about after dark Michael's Avatar
    Join Date:  May 2011

    Posts:    4,499

    My VIN:    I respect my vin enough not to whore it out among the masses.

    Quote Originally Posted by David T View Post
    If you take the weight of the car, fill the gas tank....
    If only there was a "How to" on filling the tank somewhere.
    http://dmctalk.org/image.php?type=sigpic&userid=90&dateline=161808992  9

  10. #10
    Senior Member powerline84's Avatar
    Join Date:  Mar 2015

    Location:  TN

    Posts:    767

    My VIN:    2706

    There are a 101 reasons to do your own alignments with these cars. Formula 1 cars do it but I guess Deloreans are too complicated lol . I'll be subscribing to string theory.

Page 1 of 4 1 2 3 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •