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plus sizing tires ?

Discussion in '360/430' started by bmw tuning, Apr 8, 2014.

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  1. bmw tuning

    bmw tuning Karting

    Apr 27, 2012
    178
    Portland OR
    Full Name:
    Donny
    #1 bmw tuning, Apr 8, 2014
    I have a ? about the best way to go about upsizing tires on a 360. On most cars when you do a staggered set up you want the front and rear overall diameter to match and i notice that when most people on here do a 20" or 19/20" aftermarket set up the get the sizes to have the same overall diameter. My ? is the 360 comes stock with a smaller diameter up front... should I buy tire to match the original diameters? If so why are most the high end wheel guys and most people on here getting matching diameters? TIA
     
  2. KILOCHARLIE

    KILOCHARLIE Formula Junior

    Oct 14, 2012
    321
    Cardiff, UK
    Full Name:
    KC
    #2 KILOCHARLIE, Apr 8, 2014
    Ideally remain as close to the stock diameter. I run 245/30/20 at the front 285/30/20 on the rear. You can go wider on the back (up to 335 i think) but then you would need a 25 profile tyre.
     
  3. 993turbo

    993turbo Formula Junior

    Oct 4, 2006
    317
    Puerto Banus
    Full Name:
    Remi E
    #3 993turbo, Apr 8, 2014
    I run 225/30-19 up front and 355/25-19 rears...... Yes. 355. :D
     
  4. Exotic Lambo

    Exotic Lambo Formula Junior

    Aug 15, 2011
    491
    South Florida
    Full Name:
    Gianca
    #4 Exotic Lambo, Apr 8, 2014
    1- The diameter should remain the same on front and read at all possible; if not the speedometer and odometer would not work
    properly (rear) and the car would understeer more with larger diameter at front.
    2- You can still run a larger diameter on the rear as OEM on a 19/19, 19/20 or 20/20 as it's determine by the tires.
    3- Enlarging the width will slow the car down and increase the fuel consumption as well as the grip so you want to keep it at a minimum.
    4- The new 458 Speciale runs on Sport Cup II AT 245 mm on the front and 305 mm on the rear
    5- Car manufactures usually run the best rubber that they can at it is proven to be the best upgrade to a car's handling and road feel.
    6- 19/19 235/35/19 - 295/30/19
    7- 19/20 245/35/19 - 325/25/20
     
  5. Exotic Lambo

    Exotic Lambo Formula Junior

    Aug 15, 2011
    491
    South Florida
    Full Name:
    Gianca
    #5 Exotic Lambo, Apr 8, 2014
    8- 20/20 245/30/20 - 325/25/20
     
  6. 993turbo

    993turbo Formula Junior

    Oct 4, 2006
    317
    Puerto Banus
    Full Name:
    Remi E
    #6 993turbo, Apr 8, 2014
    No edit function, Im running 255/30 front and 355/25 rears. 19''.... :D
     
  7. bmw tuning

    bmw tuning Karting

    Apr 27, 2012
    178
    Portland OR
    Full Name:
    Donny
    #7 bmw tuning, Apr 8, 2014
    from using different tire calculators and finding tire specs it looks like 235/30/20 and 285/30/20 maintain closest to factory diameters (front tires about 4% smaller than rear) but like i said and as proved above most people are running same diameter front and rear....
     
  8. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    39,174
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    #8 tazandjan, Apr 8, 2014
    Donny- 360 OEM tires have about a +4% differential front to rear. The ABS/ASR ECU does not really care about tire diameter, as long as that differential stays the same. Your odometer will be much closer, though, if you stick to the same diameter tires as OEM, which it looks like you did.

    Incidentally, all those 325-355/25 19s and 20s and similar sizes are on 12-13" wide rear wheels by whomever. Novitec and Hamann both have wheels in that range.

    The ones you chose sound pretty good. Just make sure the fronts do not rub at full lock and full compression. Bent wheels can be a problem with very low aspect ratio tires on potholed roads, and 30 series qualify.
     
  9. lukek

    lukek Formula 3

    May 2, 2003
    2,085
    San Francisco
    Full Name:
    LK
    #9 lukek, Apr 8, 2014
    I had the wrong size of tires on my 19 inch rims (previous owner upgrade). The traction control came on way too early and did not want to come off. As soon as I went back to stock rims and tires....the problem went away. Be careful to keep the same differential and calculate carefully.
     
  10. Exotic Lambo

    Exotic Lambo Formula Junior

    Aug 15, 2011
    491
    South Florida
    Full Name:
    Gianca
    #10 Exotic Lambo, Apr 8, 2014
    Just make sure that the front diameter is 94% of the rear and you will be fine; you should be looking at the tire manufacturer specification website for these diameter as the math on the size may not always be right.
     
  11. 993turbo

    993turbo Formula Junior

    Oct 4, 2006
    317
    Puerto Banus
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    Remi E
    #11 993turbo, Apr 8, 2014
    Im running the Novitec Rosso setup. 12,5'' rears. :D
     
  12. bmw tuning

    bmw tuning Karting

    Apr 27, 2012
    178
    Portland OR
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    Donny
    #12 bmw tuning, Apr 8, 2014
    Ok thanks guys so looks like my research was correct, I will try and stay as close as possible to the original O.D which looks like 235/30/20 and 285/30/20 and that should keep me near the differential between the front and rear. The only other sizes that line up are 355/25/20 and that makes no sense to go that wide on the rear when the front cant be any wider. If anything I would think that would make handling worse and increase under steer dramatically and the unsprung weight would be crazy. The wheels i am using are 20x8.5 and 20x10 w/ custom offsets to the car and i will roll the fenders up front.
     
  13. Exotic Lambo

    Exotic Lambo Formula Junior

    Aug 15, 2011
    491
    South Florida
    Full Name:
    Gianca
    #13 Exotic Lambo, Apr 8, 2014
    Although you may be right as far as the diameter those sizes will look very small on the fender opening unless you drop the car more than just a little
     
  14. bmw tuning

    bmw tuning Karting

    Apr 27, 2012
    178
    Portland OR
    Full Name:
    Donny
    #14 bmw tuning, Apr 8, 2014
    Ya i was planning on lowering it some, it seems to be necessary for pretty much any aftermarket set up on 360s
     
  15. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    39,174
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    #15 tazandjan, Apr 8, 2014
    Donny- Those tires should work fine. You cannot go much wider in the rear or the tires will be too wide for the wheels.

    Gianca- The wheelwells will look just as full as they do with stock wheels and tires. It is just that a big part of that filler (2" more) will be wheel instead of tire.
     
  16. KILOCHARLIE

    KILOCHARLIE Formula Junior

    Oct 14, 2012
    321
    Cardiff, UK
    Full Name:
    KC
    #16 KILOCHARLIE, Apr 8, 2014
    My set up is almost exactly the same as what bmw tuning is looking at, including the offsets which were measured exactly to my car. The fender opening is minimal as my arches have been rolled and I have no chance of lowering the car even slightly. They are hamann rims with deep dish at the back and the caliper clearance is around 1mm. Profile is 30 but yes I would check tyre specs carefully as I just put a new set of rears on and despite using the same tyres there was a noticeable size difference even when going from dunlop sportmaxx sp's to dunlop sportmaxx rt's which is just and updated range.
     

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