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Matching durometer reading numbers to hardness


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#1 ThunderThumb

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Posted 06 February 2020 - 07:28 PM

So what would a numerical reading on a durometer read for say a Koford WH, WX, WX+, WXX, WXXX, etc.

 

Thanks.


Earl Anderson




#2 MSwiss

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Posted 06 February 2020 - 07:51 PM

Back when I raced wings, I found that the durometer I used, the Koford factory one, varied from the smaller ones, that looked like a pocket watch, so asking another racer what hardness he was running, was pointless.

 

It was hard to get consistent readings when racing with .500" dia. rims.

 

I can't imagine it any easier now, with .650" dia., and larger rims.

 

And when you factor in a porous rubber will give you a low reading, as if it was a soft (bitey) tire, but then not bite real well on the track, I finally gave up on using a durometer, and just used testing the tire on the track to see if it was going to work that particular day.


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Mike Swiss
 
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#3 bbr

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Posted 06 February 2020 - 07:53 PM

Depends on what type of durometer you use. They have different points which affects the readings.


Mike Low
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#4 ThunderThumb

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Posted 06 February 2020 - 08:00 PM

Im looking for a ballpark figure , thanks for the info
Earl Anderson

#5 Jason Holmes

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Posted 06 February 2020 - 10:16 PM

Earl

 

Ball Park  WH 26 WX 28 WX+ 30+ WXX 32+ WXXX 36 Now all this changes the bigger the rim .615  But like Mike said best way to check is put them on the Car and run them and see if they hook up 

 

jason 


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#6 ThunderThumb

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Posted 06 February 2020 - 11:48 PM

Yes I agree about trying them on thd track but tires are so expensive these days lol
Earl Anderson

#7 Dave Crevie

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Posted 07 February 2020 - 09:52 AM

So is going to a pay toilet, but you have to do what you have to do. Different chassis will react differently to specific durometers. Just like the real car racers,

you try them out, if they don't work you sell them to some racer that can't afford new tires. 


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#8 MSwiss

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Posted 07 February 2020 - 10:26 AM

Yes I agree about trying them on thd track but tires are so expensive these days lol


Isn't it common knowledge, among the BP racers, what tire to use?
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Mike Swiss
 
Inventor of the Low CG guide flag 4/20/18
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990), eight G7 main appearances
Eight-time G7 King track single lap world record holder

17B West Ogden Ave., Westmont, IL 60559, (708) 203-8003, mikeswiss86@hotmail.com (also my PayPal address)

Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516


#9 ThunderThumb

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Posted 07 February 2020 - 11:03 AM

Yes it is but Im trying another brand and the hardness is measured by numbers not WH WX method so I was just wondering
Earl Anderson

#10 Jim Lange

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Posted 07 February 2020 - 12:30 PM

Earl, best thing to do is purchase a durometer and start measuring yourself. Don't go by numbers somebody else gives you because depending on your technique and gauge, ALL the numbers will vary. In fact, until you develop the skills needed to make the numbers repeat, the numbers will be useless. Like Mike and others stated, the bigger the hub the more difficult it is to get good, repeatable numbers but it can be done.


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#11 86ed once again

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Posted 07 February 2020 - 12:57 PM

Earl

Pretty sure if you ask Forrest he would tell you what to run. Trust me my durometer is a few points off of PA's durometer and Im pretty sure he is the only one to use numbers in categorizing tires. Best bet is buy a couple sets and try them out yourself. 


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#12 drrufo

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Posted 07 February 2020 - 01:54 PM

Each durometer might give you a different reading depending how much pressure you use to get the reading. It is more important to get the proper range meter . Buy what the manufator reccommends, an A range might be better for harder rubber than a B range meter, Taking too many readings in the same place on a tire will "harden" the rubber and give you a false reading.

 

I use a B range meter for the tires on my cars. Testing the hardness of the rubber in the middle will give you a reading that may be different than a reading on the edge due to what is under the area you are testing. Look for consisent readings by only testing the same area on each tire.

 

John Andersen


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#13 Zippity

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Posted 07 February 2020 - 03:41 PM

Not all durometers use the same pin or button for measuring purposes.


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#14 ThunderThumb

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Posted 07 February 2020 - 04:48 PM

Again thanks for all your answers , I have two durometers , one is a pin type and one is a flatter type , I know there is not one answer , but anything helps , thanks again
Earl Anderson

#15 Jason Holmes

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Posted 08 February 2020 - 12:03 AM

Earl

 

If you went to Jets 615 try 32's maybe 34's 650 the same but be easy on the break in  25-30 laps before you hammer it or you may have a wad in your hand 

 

jason 







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