Pictures of 275/60/15 on 7" Rims

Discussion in 'The Hides' started by Cutlass, Nov 25, 2018.

  1. Cutlass

    Cutlass Platinum Level Contributor

    I have 245/60/15 installed on 7" rims. I am thinking of going to 275/60/15 for the rear, but do not want to get new 7,5" or 8" wide rims. Has anyone done it and maybe has some pictures so that I can compare with the current look?
    IMG_3476_wheel only.jpg IMG_3481_Wheel only.jpg
     
  2. gstewart

    gstewart Well-Known Member

    U really should have 8" rims for that width of tire.
     
    Bills72stage1 likes this.
  3. hugger

    hugger Well-Known Member

    I would try to avoid it, only about 3in to maybe 4in of rubber are on the road under acceleration
    A 255/60 is borderline but works and looks good
     
    Paul Stewart and ilikebmx999 like this.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    It can be done, but as mentioned, that tire wants an 8" or wider rim. I had a pair of Drag Radials that size on 7" rims. Looking at them after my passes, you could clearly see 1" or more on each side of the tread was untouched. That was with 18 psi in them.

    Here are pictures of that size tire on 7" wide Buick rims, if you enlarge the picture and zoom in, you can sort of see the shading on the GN tire where it isn't hitting the road on it's outer edge.

    275Tireon7inchRim.jpg PC310021.JPG 275Tireon7inchRimB.jpg
     
    Last edited: Nov 25, 2018
  5. cstanley-gs

    cstanley-gs Silver Mist

  6. cstanley-gs

    cstanley-gs Silver Mist

    Oh, and Im running 295s on a 15x8" rim and love them.
     
  7. David Hemker

    David Hemker Well-Known Member

    The 275's will go on the 7" rim however you will need to drop the pressure to 26 psi or so to get full tire tread contact on the road.
     
  8. Eric

    Eric Founders Club Member

    1970GSX_1.jpg.cf.jpg I also have been running 295-50 /15's on 8" Buick rally road wheels on the rear for 20 years with no problems whatsoever!
    I chose them because they're the same height as my fronts which are 245-60/15's on 7" rims so...perfect stance.
    The 275's should not be any problem on 7" rims! But keep in mind those 275's are gunna be taller which will give you a bit of rake on the car.
    Eric / Oregon
     
    Last edited: Nov 25, 2018
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  9. Cutlass

    Cutlass Platinum Level Contributor

    Oh boy, I should not have asked - the picture of the 295ers make me wondering about my initial plan :)
    But I guess you have to do some bodywork for clearance, right?
    @ Eric, do you use spacers in the front, or what is the rim offset you use? My tires are by far not that much outside.
     
  10. IlliniGSX

    IlliniGSX GSX #401

    Eric, could you post some more pictures of your car specifically the tire to body clearance I want to put bigger tires on my X bit do not want to roll anything or have any rubs. Chime in out there as I want to go to the biggest tire and wheels I can without any interference. Thanks Jim.
     
  11. knucklebusted

    knucklebusted Well-Known Member

    I ran 275/60-15 on factory 7" rims for 20+ years and they work fine as long as you drop the pressure down like mentioned. I usually did a little burnout to find the correct pressure. Not as dark in the center, more air. Dark and skinny in the center, too much air. Now days I use a non-contact temp sensor to get the temp even across the tread of the tire.

    IMG_0676.JPG IMG00050-20100828-1834.jpg
     

    Attached Files:

    Cutlass likes this.
  12. IlliniGSX

    IlliniGSX GSX #401

    Thanks for the photos!
     
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yes, you can correct (band-aid) the contact patch by altering inflation pressures. That may also affect the handling and the heat build up in the tire, or maybe not. IMO, you are better off running the right rim size. Tire construction is different today. When Radials first came out, maximum inflation pressure as noted on the tire was 35 psi. Today, tires are 44 and 51 psi. My Cooper Cobras on my GS are 44 psi maximum. I run them at 38 psi. When I first bought the tires, I was running them at 30 psi. The handling was sloppy, and turn in was not crisp like it should be. At 38 psi, the ride is great, and the handling, crisp. Today's tires are made to be run at between 80 and 90% of the maximum stated on the tire. That isn't what you will see if you research inflation pressures. Most links will tell you to follow what is on the inflation sticker in the car. That is good advice for a late model (last 5-8 years or so) car. The label is based on the tires the car was equipped with at the time of manufacture. Like I said, tires are different today. That is even more true about our Skylark/GS's. The owner's manual recommended 26-28 psi (depending on loading) on a Bias Ply tire with a max inflation pressure of 32 psi. That's about 85% of max. My 98 Riviera came with Radial tires with a max pressure of 35. Tire placard says 30 psi all around. That 85% of 35. I recently had some Yokohama TRZ tires that had a max of 51 psi. I ran 43 in them and ride/handling was perfect. I recently replaced the tires with Cooper CS-5 Grand Touring tires (Great tires BTW), and they are 44 psi max. I am running 40 all around, and they have to be the best riding tires I have ever had on the car. Look at your tires and be guided accordingly.
     
    Last edited: Nov 29, 2018
    71SkylarkConv likes this.
  14. Cutlass

    Cutlass Platinum Level Contributor

    @ Greg, what size tire on what rim do you have installed in the front? In some pictures it looks like 245/60, in some other picture it looks like they are wider.
     
  15. knucklebusted

    knucklebusted Well-Known Member

    All pictures are 245/60-15 front on 7" rim and 275/60-15 rear on 7" rim. Looks and angles can be deceiving.
     
  16. rkammer

    rkammer '71 GS455 Arctic White

    Another vote for the 295 /50s on 8" rallye rims. More tread than the 275/60s and same diameter as the stock G60s were back in the day and same diameter also as the 245/60s on the front.
     
  17. Cutlass

    Cutlass Platinum Level Contributor

    THX, decision made: comes spring I'll get 275/60's for the rear
     
  18. Cutlass

    Cutlass Platinum Level Contributor

    Still, I do not know what level of bodywork is necessary.
     
  19. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    No body work required, just the correct back spacing on those 8" rims, simple as that. I have 4.5" on my rims, but the 275's are very close on one side. If I had it to do over again, I think I would go 4.75 or 5". It might get kind of close to my 3" exhaust tail pipes, but that's about it. You have to carefully measure YOUR CAR. It is not uncommon to have more room on one side than the other. The body most times doesn't fit evenly on the frame.
     
  20. Bigpig455

    Bigpig455 Fastest of the slow....

    ran 275's on 7 inch rims for a while, only got rid of them because they were VERY old. At 23psi, was able to pull off 1.82 60 fts time after time, so clearly there was no shortage of treadwidth..I have been happier with 245's though, the rear sidewalls or shorter and the rear doesnt sway as much at 35-40 psi...

    upload_2018-11-29_21-11-33.jpeg
     
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