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Thread: Choosing a Tire Durometer

  1. #16
    Join Date
    Nov 2003
    Location
    Koria Finland
    Posts
    318
    There's no point in the absolute figures - a 50 compares to a 45 on another type A (cheap) durometer. But lots of sense to make comparisons, under the same brand of rubber there's a lot of variation, 10 - 20 % easily.
    zipper

  2. #17
    Join Date
    Feb 2005
    Location
    Chesapeake, Va.
    Posts
    794
    Like many racers who have been around for a while I use the Longacre durometer. I use it for comparison only in an effort to match tires as closely as possible. One thing I learned over the years is that a car will handle better with a matched set of tires and be much more predictable. One thing you should do first is use your tire grinder to get a flat surface. Most tires right out of the tube will be concaved, just like newly in the center, just like newly rubbered hubs, and your readings will be wrong. I always take a surface cut before I duro the tires. Remember that heat and cold affect the tires, I duro mine indoors at around 70 degrees.
    I've done so much with so little for so long it seems like I can do anything with nothing at all.

  3. #18
    Join Date
    Aug 2010
    Location
    Arizona
    Posts
    621
    Click image for larger version. 

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ID:	12510Wouldn't you want to use a gauge that fits the purpose? Such as measuring the softness of a tire under the same load as what the completed car will exert on the tire to track contact patch?

    An "A" scale durometer requires a force up to 822g or 1.81 pounds, our cars usually weigh a little less than that!

    To me after looking at a chart on types of durometer the "oo" scale seems to fit the range for slot cars.
    I will try to upload the scale as it's a great visual!

  4. #19
    Join Date
    Mar 2006
    Location
    Sydney, Australia
    Posts
    189
    I expect my G7 wing car exerts at least that in down force.

  5. #20
    Join Date
    Nov 2003
    Location
    Koria Finland
    Posts
    318
    G7 measured in a wind tunnel @ 150 km/h did about 150 - 200g afair when measured about 10 years ago.
    zipper

  6. #21
    Join Date
    Aug 2010
    Location
    Arizona
    Posts
    621
    zipperi...
    looks like the type "OO" would be the right type of meter than.

  7. #22
    Join Date
    Nov 2003
    Location
    Koria Finland
    Posts
    318
    Might be - but I'm quite happy with "A" measurements - between 30 and 50+/100 with current hard tires on .500 to big hubs. Gives a good reference to compare - just must be careful not hitting the holes in the rims.
    zipper

  8. #23
    Join Date
    Jun 2006
    Posts
    220

    Matched hardness dosent always work best

    Sometimes you run faster with a soft tire on one side and a hard tire on the other side.
    The only real way to know what tire and hardness works best is to test different tire combinations.

    A lot of times when I cant get any tires to work, I try some real off the wall combinations. Sometimes you will stumble on something that really works. Mix and match then...test and retest.
    Support Your Local Raceway !!
    I beat John Cauthen !

  9. #24
    Join Date
    Jun 2002
    Location
    Wellington, New Zealand
    Posts
    4,470
    Am I safe in assuming that "softer" (a lower reading on the durometer scale) means better traction?

    Zippity

    "Rules are written by FEAR; and that Racers are motivated by the Fear that somebody may have something that gives others an Edge." - Rocky Russo



  10. #25
    Join Date
    Jun 2002
    Location
    St Charles, Illinois, USA
    Posts
    2,319
    Too soft in a banked turn is like a flat tire on a curve - into the fence.
    l.d. kelley, M.A. Ramcatlarry@aol.com

    60 year pin 1959-2019
    Racing slot cars in America
    USRA 2019 member
    IRRA, ISRA/USA, Hardbodies 1/24 &
    1/32 - Great Lakes Slot Car Club
    retired raceway owner 1992-2007
    Omni/Cidex service center

  11. #26
    Join Date
    Jun 2002
    Location
    Wellington, New Zealand
    Posts
    4,470
    Quote Originally Posted by Ramcatlarry View Post
    Too soft in a banked turn is like a flat tire on a curve - into the fence.
    All of our tracks out here in NZ are FLAT
    Zippity

    "Rules are written by FEAR; and that Racers are motivated by the Fear that somebody may have something that gives others an Edge." - Rocky Russo



  12. #27
    Join Date
    Mar 2003
    Location
    Dallas, Texas
    Posts
    312
    Dug this one up from the depths of the slot car mortuary
    "Never underestimate the predictability of stupidity"

    Archie King
    2018 TSRA Series Group 7 Champion
    2018 HillBilly Box World Record Holder 1.907
    2016 HillBilly BoxStock Champion
    2014 TSRA Series Group 7 Champion

    Team KOFORD
    http://www.koford.com/slot/

  13. #28
    Join Date
    Jun 2002
    Location
    Wellington, New Zealand
    Posts
    4,470
    Moi?


    There's no such thing as a stupid question - only stupid answers
    Last edited by Zippity; 02-09-2018 at 02:34 AM.

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