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15 vs. 16 vs. 17 inch rims... a tire question

Discussion in 'Shop - Miscellaneous' started by pphat, Oct 26, 2003.

  1. pphat

    pphat Member

    Joined:
    Jun 19, 2003
    Location:
    San Francisco, CA
    Random thought: my truck came w/ 16 inch wheels. I'd like to put 33x10.5 inch Bajas on it. Which would require 15 inch wheels. Or buying a metric sized tire for the 16 inch rim. 285/75R16 or thereabouts.

    The tires for the 15 inch wheels cost less... more folks I know carry 33s on 15 inch rims... tire shops in Baja seem to have more tires for 15 inch rims laying about... but I'd have to buy 6 new wheels.

    Of course, my stock rims are 16x7 and BFGoodrich says I should be running at least a 7.5 inch rim for the 285/75R16. So, in theory, if I can't run the 285/75R16's on 7 inch rims, I'm buying new rims anyhow.

    And, hey, while I'm reading tire specs at 1AM on a Saturday night, Goodrich has 285/70 tires that run on 17 inch rims.

    So... dumb question: are there any advantages or differences a mere mortal would feel w/ the same (roughly) tire size on a 15 vs. 16 vs. 17 inch rim? I mean, I get sidewall stiffness on a sportscar w/ 50 or 60 series tires improving cornering over a 70 series tire... but what does sidewall size mean to a pickup going off in Baja?

    Anybody got a clue for me???
    Patrick
     
  2. mcne

    mcne Member

    Joined:
    Apr 20, 2003
    Location:
    originally Corona, Ca. now Joplin, MO
    This has been discussed before. Try doing a search. The way I understand it is the bigger the rim the more weight you will save with the same size tire. At least with aluminum rims. Weight is very important, just notice how many threads are about weight. I doubt you would notice the difference on a prerunner. Also keep in mind that rims are easily damaged. What does a new/used stock rim cost? How available are they? Initially it seems costly to purchase new rims but in the long run I believe it is worth it. Last thing I would want to happen to me is to bend several rims and be forced to buy aftermarket rims with a different offset or width to get buy. My two cents. Brian.
     
  3. ntsqd

    ntsqd Active Member

    Joined:
    Sep 17, 2001
    Location:
    Here
    If your truck came with 16''s, running 15's is likely not an option. Your brake calipers will rub on 15's. I know the late model GM's will.

    I'm running the 285/75R16's on stock GM HD Alloys. They went to El Currenta (RM 616) and back under a 3/4 4wd Suburban loaded down with all of the crew's gear. No worries. Those GM rims are something like 6.75" wide. Running on a slightly narrower rim than spec helps protect the rim at a mild cost in tread life.

    Same sidewall stiffness applies to trucks. Imagine driving 44's on 15" rims and how bad they would suck in a corner. While you're not trying to achieve a 1.0g lateral acceleration, sooner or later a street driven truck will have to make a swerve around some moron. Sidewall stiffness will be a big part of determining whether that's a white knuckle event or not.
     
  4. pphat

    pphat Member

    Joined:
    Jun 19, 2003
    Location:
    San Francisco, CA
    >>This has been discussed before.
    Any suggestions on what to phrase to search w/? I spent over an hour searching every combo of rim/tire/wheels/size/diameter I could think of before I posted this question. I didn't find a definitive answer.

    Found lots of great info on tires and wheels... just not much on rim diameter. Thanks,
    P
     
  5. hoeker

    hoeker Well-Known Member

    Joined:
    Oct 9, 2002
    Location:
    holland, MI
    i don't recal reading about this in the last year so i'll see if i can help.
    1st, Thom is right and a 15" rim is unlikely to fit on anything that came stock with 16's. be thankful, you have bigger brakes because of it.
    2nd, a 285 75 r16 works very well on stock wheels, but they are not as wide as the comparable 33x12.50 r 15, not sure what's available in 17" tires.
    3rd, i tried running 35 x12.50 r 15's on my corr truck and hated the feal compared to the same tire in a 33. the only differance was sidewall.
    if the tire is the size you want i'd say to save the bucks and run the stock wheels, if you think you need a wider footprint look into the 17's but you may not find the size you want.

    hope this helps

    www.rosshoek.com
     
  6. pphat

    pphat Member

    Joined:
    Jun 19, 2003
    Location:
    San Francisco, CA
    Cool... thanks everybody!
     

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