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Technical I need so advice on track width

Discussion in 'Traditional Hot Rods' started by Ratspit, Oct 20, 2018.

  1. Ratspit
    Joined: Dec 6, 2017
    Posts: 287

    Ratspit
    Member

    I am in the process of building a traditional fenderless 34 Ford pickup and need some advice on track width. My front end width is defined by the axle width and wheel offset. Right now outside rim to outside rim is 61.50". Mounting surface to mounting surface on the front axle is 57". Since I am having Winters build a QC for the truck I have the opportunity to have the axle width built to my spec.

    So my question is. What is to optimum track width front to rear? Is it best to have the outside track width equal front and back? Or would it be better to take the center line of each track width and have those widths equal front and back? In the latter scenario, since the wheels are wider in the back, the outside track width would effectively be wider in the rear.


    Wheels and tires are as follows.
    Front - 18x3.5 wire wheels w/6.00x18 tires (offset 1")
    Rear - 18x5.5 wire wheels w/7.00x18 tires (offset 2.5")
     
  2. To my eye, center line to center line would look best.

    Mick
     
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  3. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    Are you talking offset, or backspacing?

    If you are measuring from the center line of the wheel, to the wheel mounting flange, on the inside, you are measuring offset.

    A 3-1/2" wheel with 1" of offset has 2-3/4" of backspacing. This seems unlikely on a wire wheel.

    A 5-1/2" wheel with 2-1/2" offset has 5-1/4" of backspacing. This also seems likely on a wire wheel.

    If you are measuring from the wheel lip on the inside, to the wheel mounting flange, on the inside, you are measuring backspacing.

    A 3-1/2" wheel with 1" of backspacing has 3/4" of negative offset (correctly expressed as -3/4" offset).

    A 5-1/2" wheel with 2-1/2" backspacing has 1/4" of negative offset (correctly expressed as -1/4" offset).

    Also, track width is the distance from the center line of one tire, to the center line of the opposite tire. It may, or more likely may not, have anything to do with the axle wheel-mounting-surface to wheel-mounting surface (WMS-to-WMS) measurement.

    Best thing to do it stand the rear wheels up where they look good, and measure between the mounting surfaces, and call that the WMS-to-WMS number.

    I am not trying to be a pedant. These terms are important. If you use the wrong ones, and a supplier does not understand that you did, you might be out thousands of dollars in parts that you cannot use.
     
    Last edited: Oct 20, 2018
  4. When I built my deuce pickup it never entered my mind, I just knew what size my wheels & tires were going to be but I would imagine the front was a bit narrower than the rear. HRP
     

  5. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 3,375

    GearheadsQCE
    Alliance Vendor

    My first inclination was to agree with lurker mick. But, I would also look at the space between the pick-up box and the tire. From the rear it might look better to tuck them up tighter. If you already have the wheels and tires, a mock up is priceless.

    As Gimpy said, the best way is to measure between the wheel mounting surfaces and order the rear end to fit.

    I'm a dealer for Winters. If I can help, send me a Conversation.
     
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  6. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    Not just a dealer, but a good one, with excellent customer service (I'm a customer!). I know you are not here to sell, but if you were, I'd recommend you!
     
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  7. Ratspit
    Joined: Dec 6, 2017
    Posts: 287

    Ratspit
    Member

    My mistake. I was talking backspace.
     
  8. Ratspit
    Joined: Dec 6, 2017
    Posts: 287

    Ratspit
    Member

    So if I keep the track width (centerline of wheel to opposite centerline) the same for front and rear, the overall width at the rear will end up being 2" wider overall or an inch on each side. The space between the tire and bed will be 1.75" on each side. Seems like that works all around.
     
  9. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    You can build a car with math alone, but the proof of the pudding is in the tasting.

    You will need to be satisfied with the look.
     
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  10. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    Back in the days when I was doing this sort of thing full-time, I kept a small array of discarded axle shafts (often broken ones from racers), and a bunch tube/pipe that would slip snugly over them.

    That way, I could make a mock-up axle, to determine wheel position, without taking chances, or spending money.
     
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  11. blowby
    Joined: Dec 27, 2012
    Posts: 8,661

    blowby
    Member
    from Nicasio Ca

    Bump, and a little off 'track'. Yesterday I saw an older XKE Jag going down the highway. Beautiful cars that I have always admired. But the darn wheels are so far inside the body. Today I ran into a friend who's into old Brit cars, and he tells me this was due to being designed to operate on roads originally created by Roman chariots! The DB4 also being one of the last examples. I tell him he's full of shit but he insists it's true. So, in addition to he and his pals having a good belly laugh as I walked away, I'm asking you guys.
     
  12. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    ^^^^^^^it’s true! At least it’s widely accepted to be true. The Romans apparently had a ‘standard’ track width on their chariots and, presumably, other wheeled vehicles. The roads were rutted according to these widths and any other wheeled vehicles that followed were easier to operate with the same track. Given the Roman’s wide spread dominance, and no better reason to alter the track width, it became the de facto ‘standard’ throughout the then ‘known’ world.

    For more detailed info on this subject you might try Google or Wikipedia.
     
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