Cooper wide tires

Discussion in 'The Hides' started by wunquik86', Feb 14, 2017.

  1. wunquik86'

    wunquik86' Well-Known Member

    I recently purchased a set of 675 series Ridler 15 inch wheels in 7 and 8 inch for my 1971 Buick Skylark. I put 235's on the front and 255's on the back. Some of the local car guys that have seen the car thought the back should have a wider tire. So without thinking (sound familiar) i purchased a pair of 295's. These are all Cooper Cobras. I mounted one of the 295's on one of the 8 inch wheels. It appears a bit too wide for the wheel, (side wall appears to roll out too much). Am I correct in this assumption and what back space should I have for a 295. Which of the wheel companies makes a 10 inch x 15 inch wheel that won't break the bank? I'll also need a matching pair of 7 or 8 inch. Thanks in advance for your help.
     
  2. 2001ws6

    2001ws6 last of the v8 interceptors

    I just put 295/50/15's on. Put them on a 15x10" wide and 5.5" back spacing. Not sure on what rims you will like that wont be expensive.

    IMG_1312.jpg
    IMG_1313.jpg
     
  3. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    15X8 is okay for a 295/50R15 they should not bulge too much... You would get more of a contact patch on the pavement with a 15x10 though...

    I have a set of 295/50R15 on 15x12 rims for chassis dyno use so I don't tear up the drag radials on the rollers... As you can see they fill out a lot more on a wider rim:

    [​IMG]

    [​IMG]
     
  4. wunquik86'

    wunquik86' Well-Known Member

    Super job guys, I really appreciate the info and the pictures. I'm just not satisfied with the look on the 8 inch wheel. I may have some good news. My tire guy called me and advised he has a customer that is looking for the type of setup I have to go on a 1966 chevelle. If I can find a set of wheels for somewhere in the neighborhood of say $800 bucks I'll sell him mine and go from there. My tires and wheels have approx 60 feet of road miles on them. I've rolled it out of the basement to let it run on 2 occasions, and rolled it back in. Being somewhat of the older generation I'm sorta hung up on the 5 spoke torq thrust look. Anyone know when the National Hot Rod Show in Louisville, Ky happens to be? It can't be far off.
     
  5. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    That is good news that you may be able to sell your rims for a good deal!

    Here are some rims that are affordable and look good in my opinion... I had them on my old car, they came from summit. They were 15x10 and 295/55R15 fit perfectly under my old 71 Skylark:

    https://www.summitracing.com/int/se...t-polished-wheels?autoview=SKU&ibanner=SREPD5


    And here are some other 15x10 wheels from the same brand:

    https://www.summitracing.com/int/se...r=Ascending&retaillocation=int&ibanner=SREPD5
    [​IMG]

    [​IMG]
    [​IMG]

    Or tub out the car like mine:

    [​IMG]
     
  6. 87GN_70GS

    87GN_70GS Well-Known Member

    Will the 12" wide wheels fit with no mods? Stock ride height?
     
  7. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Hi there, no I don't think the 12 inch rims would fit without mods and at stock ride height...btthe widest I would go is a 10 inch rim and 325/50R15 but your backspace needs to be perfect and maybe raised up. The best safe best with stock ride hight and no trimming is a 295/55R15... I find the 50 series looks a little short. In the one pic above with the primer car I had 285/70R15 and those fit great too...

    I'm using those 12 inch rims on my tubbed out cat with narrowed rear end and custom frame. On the chassis dyno it was going to be too hard on the 33 inch tall by 20 inch wide drag tires so I setup that set for dyno only use... Drag tires can explode on the rollers so it's dangerous to use them.

    Then for the street I have 14 inch wide rims with 31x16.5 Mickey Thompson sportsman pros
     
  8. cstanley-gs

    cstanley-gs Silver Mist

    295/15-15 on 15x8 rims
    <img src="http://i173.photobucket.com/albums/w75/cstanley444/GS455/IMG_2828.jpg" border="0" alt=" photo IMG_2828.jpg"/>

    <img src="http://i173.photobucket.com/albums/w75/cstanley444/GS455/IMG_2824.jpg" border="0" alt=" photo IMG_2824.jpg"/>
     
  9. wunquik86'

    wunquik86' Well-Known Member

    Those tires don't look bad to me at all. If you run a straight edge across the face of the tire does it show the tire may catch the inner lip of the fender about a third of the way up the wheel from the door side of the wheel opening? My car is actually setting above the tire at present but I'm not sure if it will stay that way. I am considering putting a set of "Air Lift" air bags under it to hold it where it is. I'm gonna have my daughter try and put a couple of pics on here of my car from the side with the 295 on it and the side with the 255 on it. Then you will have a clearer idea of where I am. I greatly appreciate the experienced input here guys believe me I'm most grateful.
     
  10. gs66

    gs66 Silver Level contributor

    The widest I've used on 8" are the 275's, seems like the 295's like the 10" wheels.
     
  11. cstanley-gs

    cstanley-gs Silver Mist


    It's close. But they've never scraped the inside if the wheel.

    [video]https://youtu.be/4JJ3przkaIc[/video]
     
  12. wunquik86'

    wunquik86' Well-Known Member

    I sold my wheels and tires. A little while ago I also ordered a set of U.S. Wheels 5 spoke 'torq thrust pattern" from jegs in 15 x 9, 5 inch BS and for the front 15 x 8, 4 inch BS. I used the formula I saw on here and the 295's call for an 8.71 inch wheel. I think these 9's should be spot on. What do you think guys?
     
  13. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Yes 9-11 inch rim is perfect for the 295
     
  14. Dano

    Dano Platinum Level Contributor

    I know you sold them, but Cooper calls for 8-10" rim width which will typically correspond to the TRA (Tire & Rim Association) specifications. There are specifications & standards for every size tire made listed in the TRA "Yearbook". Cooper lists a 9.5" measuring rim width, which is the rim width all the tires dimensions are based on and usually what the manufacturer would consider optimal. Typical rule of thumb is a rim width of approx. 75% of section width which as the OP indicated comes to 8.71".
     
  15. OZGS455

    OZGS455 Oh what a wonderful day!

    Ive just had true 10" rims fitted to my Buick centres (11" rim edge to edge)...I worked on a 5.75" backspacing, probably 6" would've been better, but with Vitour Galaxy 295 50 15 they just clear on the outer and there's a good half inch clearance behind.
    pics are on my phone so Ill put em up next post
     
  16. OZGS455

    OZGS455 Oh what a wonderful day!

    heres pics
     

    Attached Files:

    DasRottweiler and Mike B in SC like this.
  17. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    That looks great!

    I just got some 295/50R15 and 235/60R15 for my 75 Regal. 15x8 rims.
     

    Attached Files:

  18. 87GN_70GS

    87GN_70GS Well-Known Member

    I think your 1/4" offset is better (5.75" bs) than 1/2" offset (6.0" bs). The reason is, as the body rolls (and the tire tucks up into the fender) the top of the tire rotates toward the center of the car: the top outer edge rotates away from the qtr panel lip and the inner rotates towards the inner wheelhouse. On the opposite side the opposite is true, but the top of the tire is going to be out of the qtr panel. As you add in forces from hard cornering, the inner wheelhouse clearance on the tucked in tire gets worse, so more backspace hurts there instead of helps
     
    OZGS455 likes this.
  19. OZGS455

    OZGS455 Oh what a wonderful day!

    Sounds good to me!...Ive done some pretty hard cornering to test it but not with any people in the back seat, thatll be the ultimate test.
    If need be I can shave a little off the lip mould and even the lip itself.
    dont really think itll come to that though.
    Car just looks 'right' with this setup!
    also the front 245 60 15 have the same rolling diameter as the rears and Ive used the same size and brand tyre as my spare too so in the unfortunate situation I get a flat tyre then Im not gonna stress out the LSD unit in the differential.
     

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