Tire/wheel size identification

Discussion in 'A boatload of fun' started by fullmetaljacket, Jan 3, 2020.

  1. Hello all, I’ve got a 72 Riv and would like to identify the rim size and tire size for the attached pics...does anyone know or have more details on this setup? Also, does it also appeared lowered at all? Thanks for any help or links you might have!

    Attached Files:

  2. pbr400

    pbr400 68GS400

    Rims appear to be factory ‘Road Wheels’ which are 15x6, 5” bolt circle. There is a version of that wheel used on ‘80s wagons that measure 15x7. The tires look to be at least 235/70/15. Obviously those are a specialty tire, provably from either Coker or Diamondback. It’s definitely been lowered.
  3. Thanks Patrick!

    I would like to mimic that look as best i can. If I purchased 15x8 ralley style wheels such as these by Wheel Vintiques (https://www.summitracing.com/parts/wvi-57-5834042) and used maybe the size you suggested in the Coker 3" whitewalls, maybe i could be close. I would assume a 15x8 would fit and would be a bit more 'normal' for findings tire options. Any comments on that rim and size for a 72 Riv?

    Finally, about how much lower do you think those images are? I am also interested in this Jamco kit (https://www.jamcosuspension.com/products/sfID1/31/sfID2/42/productID/1629) which has 1", 2", and 3" drops. I am assuming a 3" but really am just guessing.

    Thanks for any comments or ideas to get close to that look...thanks!
  4. pbr400

    pbr400 68GS400

    You can’t use the rims in your link; they’re the wrong bolt pattern. Big cars and Rivieras are a 5” bolt circle ‘Road Wheels’. GSs, Skylarks, Regals etc. were ‘Rally Wheels’ and 4 3/4” bolt circle. All the repros are 4 3/4”. As far as I know, nobody reproduces the Road Wheel and the 7” wide version is hard to find. I’d bet money that the car in your photo is on 15”x6” wheels. As for tire size, I’m purely guessing, but the folks at Coker might be able to squint at your photos and give a fair guess. The main criteria will be ‘does it work on a 6” wide wheel and have a similar overall height to original?’ (OE was about 29” tall). I think the car is two inches lower but it’s hard to tell. Wild Bill has a line on some wheels...


  5. Extremely helpful Patrick, thank you again! It's amazing that i've been staring and reading different posts for hours and still didn't clue in to what you just taught me. Thx! i'll keep learning and digging before i pull the trigger...
  6. Paralyzed with options and trying to figure this out. Tried to ask Coker but they will only say what fits from them from a factory perspective (they show these two H78-15 https://www.cokertire.com/catalogsearch/result/index/?q=H78-15&sidewall_style=1774).

    I know we can't tell exactly without reading the side of the tire, but is there any strong opinions about the pictures i posted...are they likely original bias-ply h78-15 size or maybe something like the 235/70 or 235/60? I'm trying to figure out by how much black tire is showing past the whitewall in those pictures. It 'seems' like they are a 60 aspect...but maybe what i'm trying to do is impossible because who knows how much air is in the pics on the car vs a stand alone tire in a coker image. I absolutely want the large whitewall and a tucked look just afraid i'll end up with 3 or 4 sets of tires trying to guess! thanks for any input!
  7. pbr400

    pbr400 68GS400

    235/70 is about the right height; 235/60 is too short. I agree that what’s in the photo looks wide, but to get a 60 series the right height you’re looking at potentially a 275, which is likely too wide for the rim. (Although Wild Bill -I think-ran BFGs that size on his blue Wildcat. Ask him (Topcat on here)). Try Diamondback Classics; they take modern tires and put custom sidewall treatments on it. Also check out Lucas’ (72Mach1) Cadillac. He has wide whites and knowledge about fitments.
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I can tell you the original tire size H78-15 was 28.36" overall diameter with a section width of 8.85".

    The closest P-metric tire is a P225/75R-15. That tire has a section width of 225mm. There are 25.4mm in one inch, so 225/25.4 = 8.85". The overall diameter of the tire can be figured by converting everything to mm, adding, and then dividing by 25.4 to get back to inches. The 15" rim is 15 X 25.4 = 381mm. Each sidewall is 75% of the section width (225mm), so 225 X .75 =168.75mm. The overall diameter would be 2(168.75) + 381 = 718.5mm, 718.5/25.4 = 28.29" That's almost an exact match for the stock H78-15


    Last edited: Feb 15, 2020
  9. Thank you Larry!
  10. bherbert

    bherbert Well-Known Member

    For reference - I have 235/75 on my Riv on stock 6" rims. Stock height but thinking of dropping it 1".
    Whitewall tires are Hankook and were about $80 a piece. 235/70 coker whitewalls are more like $270 a piece.

    Attached Files:

  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The P235/75R-15 are taller than stock at 28.87" tall. The P235/70R-15 are closer to stock height at 28".

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