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308 tire width?

Discussion in '308/328' started by keithblackwell, Jan 31, 2007.

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  1. keithblackwell

    keithblackwell Karting

    Jul 7, 2006
    87
    St. Louis
    Full Name:
    Keith Blackwell
    #1 keithblackwell, Jan 31, 2007
    I have a 308 with the original 14" tires.... time for new ones and I want to keep the original rims. I know my choices are limited, but is it possible to put a WIDER and/or lower profile tire on? I don't do tracks,racing, etc...... just an occasional "joy ride". A speed rating of at LEAST what the originals were, would be desired. Any downside to this?
    what do you guys reccomend? Sizes? Brands?
    I know this has been touched on before....just looking for new/updated ideas.
    Thanks!
     
  2. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
    10,676
    Worldwide
    Full Name:
    Steven
    #2 enjoythemusic, Jan 31, 2007
    largest would be 225 front and 255 rear IMO. Stock is 205 front and 225 rear i think. 16 or 17 inch rims are fine for most folks.
     
  3. mambodave

    mambodave Formula Junior

    Jun 3, 2005
    531
    Charlotte NC
    Full Name:
    Dave
    #3 mambodave, Jan 31, 2007
    im running 225 fronts and 245 rears.. but on 16's

    check tire rack online for 14 sizes and see what you come up with on widest.
     
  4. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,367
    NY
    #4 Steve King, Jan 31, 2007
    I have 235-60-14 all around but the correct size would be 245-60-14 which is the same as the 205-70-14 OEM tires. The speedo difference between the 235 and the 245 is not a problem. Go to the tire sites and see what comes up.
     
  5. rtking

    rtking Formula Junior

    Mar 5, 2006
    703
    Huntington Beach, CA
    Full Name:
    Bob King
    #5 rtking, Jan 31, 2007
    205/70-14 equates to a 25.299" diameter.

    235/60-14 will give you a 25.102" diameter, and your speedometer will read fast by .008%. Negligible difference. (At 60mph, your speedo will show 59.5 mph)

    245/60-14 will give you a 25.575" diameter, and your speedometer will read slow by 1.089%. (At 60 mph, your speedo will show 60.65 mph)

    A quick calculation for tire diameter is:

    ((((205/25.4)*(70/100))*2)+14)

    where the bold numbers are the tire size. Since tread width is measured in millimeters, you divide by 25.4 (25.4 millimeters = 1 inch). The sidewall number (in this example is 70) is actually a percentage of tire width - so yo% of 205 mm. Since it's a percentage, we divide by 100. We multiply the product of the calculation by 2 since, as you measure the diameter, there are two sidewalls to account for. Then we add the wheel diameter (14" in this case) for overall tire diameter. If you want circumference, multiply that product by 2*Pi.

    Another thing to consider is wheel width. You may not want to put a very wide tire on a narrow wheel since you'll be flexing the sidewall inwards, pulling up the outside tread, and may degrade handling. A 7" wheel can probably accommodate 235 and 245 widths, but I personally would prefer at least a 7.5" wide wheel for a 245 or 255 width tire.

    Hope that helps.
     

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