Just joined? Please introduce yourself.
Page 2 of 2 FirstFirst 12
Results 11 to 19 of 19

Thread: Back space

  1. #11
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    Warren, you're not concerned about the edge of the wheel...you're concerned about the center of the wheel, which determines where the edge of the tire is. If the wheel center moves, the tire moves.

    This can get a little confusing, as you can see. That's why I designed the calculator to calculate the track based on wheel mounting width and backspacing or offset, and the clearances depend on tire size, not wheel size. Actually I use offset for the calculations, even if the user enters backspacing.
    Last edited by chevynut; 04-08-2015 at 09:05 AM.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  2. #12
    Registered Member warren57's Avatar
    Join Date
    Jul 2012

    Member #:755
    Location
    Colorado
    Posts
    569
    Edited my last post, see if that makes sense.
    And yes it gets a bit confusing!!!!
    Thanks

  3. #13
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    Quote Originally Posted by warren57 View Post
    so, if a 6" wheel is 7" over the bead, then at 3-1/4" bs would put the inward edge 3-1/4" in from the mounting surface. Thus giving you 3-3/4" outward.
    Yes, that's correct.

    A 7" wheel is 8" over the bead, then a 4" bs would put 4" inward from the mounting surface and 4" outward, or 1/4" less clearance to the fender than the 6" wheel.
    Correct?
    Yes, that is correct.

    However, the edge of the wheel isn't the issue, as I already explained. It's the edge of the tire that matters. So you have to find the CENTER of the wheel, and calculate where the edge of the tire is from that.

    The 6" wheel you are talking about has 1/4" negative offset, and the 7" wheel has zero offset. So the 6" wheel center is further outboard, making the same tire on the 6" wheel closer to the fender.

    I measured my disk kit, I am sitting at 61" wide to the mounting surfaces.
    That's what I thought you should get.

    Using your tire/wheel calc program. Using a 6" wheel, 3-1/4" bs and 205 tires, I should expect .71" clearance. Now should I be plugging in a 6" wheel or should I be plugging in the 7" (over the bead) size?
    The calculator says to plug in the nominal wheel size. So if it's a 7x15, you'd plug in 7". That's what my original spreadsheet says. I didn't do the online version of the calculator but the guy who did it used my formulas after asking for my permission.

    If I use 7" width and the same bs the program says .21" clearance.
    Yes, but the backspacing on the 7" wheel you've been talking about is different. To avoid confusion, imo it's always better to talk offset. Offset is independent of wheel width.

    Pretty close, but considering wagon front coil height and stock spindles, it may work. Don't have any other option. Guess I'll give it a try. If it's to close, the fix would be a 0 clearance kit and I can make that change easy enough. All it take is dollars!!!
    Thanks
    If your car is stock height or higher, you shouldn't have much of an issue since the fender lip is over the top of the tire. IMO sometimes it looks funny when the tires stick out that far. And if you're turning hard and hit a big dip, you could have rubbing issues. I think there's a disc brake kit for a stock spindle that has a lot less offset than the Chevelle setup, and that's what I'd probably do if you want to pull the tires in further.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  4. #14
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    Your tires are going to be 70" wide outside and the fender lips are around 71", I believe. The calculator makes an assumption on your fender lip width, and you should measure your own car to be sure. The best way to do that is with plumb bobs and marks on the floor.

    With a car that's lowered, or that's likely to see dips on hard turns, like turning into a driveway, I usually recommend that the front tires are no more than about 67.5" outside to outside. Some guys have had success at 68" but it depends on how much the car is lowered.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  5. #15
    Registered Member warren57's Avatar
    Join Date
    Jul 2012

    Member #:755
    Location
    Colorado
    Posts
    569
    Reading your post gave me a flashback to the mid 70's. We all bought Chevy short bed 4x4 trucks, put 1200 15 tires on them with the deepest reversed wheels we could get. The tires had to be sticking out past the fenders by 3-4". Then we stuck on the deepest tread knobby tire we could find.
    And we thought they looked great, high and wide!
    Now look, everything is down in the weeds, not a look I care for! And the 60's Impalas are down in the weeds with 20" tires reversed ans far as possible.... I call them inside out tires! Stick on gold spoke wheels and you really have something.... I'm just not sure what it is you've got!
    Thanks for your pointers on wheels and tires, I'll keep you posted on what I decide and how it works out...

  6. #16
    Registered Member warren57's Avatar
    Join Date
    Jul 2012

    Member #:755
    Location
    Colorado
    Posts
    569
    well, here they are. All is well
    Attached Images Attached Images

  7. #17
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    Looks good Warren.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  8. #18
    Registered Member warren57's Avatar
    Join Date
    Jul 2012

    Member #:755
    Location
    Colorado
    Posts
    569
    Thank you

  9. #19
    Administrator 567chevys's Avatar
    Join Date
    Oct 2010

    Member #:3
    Location
    Woodland Washington
    Posts
    2,413
    Looking good Warren ,
    Is that the car that had the 454 in it ?

    Thanks Sid

    1955 2 DR Post
    1937 Chevy Coupe
    2023 Ford Super Duty F350 TREMOR
    2019 Corvette Z06
    1955 Chevy Nomad
    1935 Ford 2dr Slant back I have 4

Page 2 of 2 FirstFirst 12

Posting Permissions

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