Durometer?

[raffaelli]

Anyone know where to get one that isnt $250+?

[SteveP]

It's almost impossible to find one for less that. I've only found one tire durometer that is even remotely effective at measuring foam tires that are already mounted on the rims, or rubber tires at all. It measures hardness on a "Micro A" scale, which allows sampling of materials as thin as .050". Any other durometer requires a material with a minimum of 1/4 thickness to get accurate readings. So unless you're able to test the foam or rubber before it's processed into a tire that you buy at the store, you're not going to get and accurate reading with a durometer that costs less than $600. Heres a link. http://www.durometer.com/1600.htm

[raffaelli]

Thanks, Steve. I was in contact with the people at that link. They also suggested this one. Then I saw that Paris and Ashford Hobby have one for about $250. Just thought I's ask before I plunk down the cash. Didnt Max Mod have one for like $50?

[SteveP]

The Paris and MaxMod durometers are Shore A scales I believe, which requires a minimum material thickness of 1/4-inch. Manufacturers can use these units because they can stack the material to get a measurement. For our use however, they're not going to be that accurate. I may be too demanding with respect to accuracy in the readings, but I personally wouldn't spend the money a piece of equipment that's not designed to work for our application.

[raffaelli]

Thanks for the input Steve, I'll see you at Xtreme in the spring.

Thanks
Chris

[raffaelli]

I has some communication with Ron Paris, he mentioned that shore A is the industry standard.

[SteveP]

Shore A is the industry standard, but the manufacturers of the durometers require a minimum of 1/4 thickness to get an accurate measurement. The tire manufacturers can measure the foam before its mounted and trued. Once they're on the rims and cut down to size, there's not enough material to get an accurate reading. This is from the manufacturers of the gauges, not me. I'm suggesting a micro A gauge for us non-manufacturers because it's the only one that can be accurately used on the once the tires are mounted.

[raffaelli]

I see. So micro A and A are the same scale, just difference in thickness.

Thanks again.

[This message has been edited by raffaelli (edited 01-04-2001).]

[SteveP]

I would have to confirm it with Rex, but I believe it's the same scale.

[raffaelli]

here is a response I received from rex about which scale would be appropriate for our use:

If the tires read 25 in the "A" scale, that means that the gauge has
penetrated .075" into the tire. A material that is 25 in the "A" scale
would roughly be a 30 in the Micro A/(M) scale with .035" of penetration
into the material. I think the most suitable scale for your application
would be the type "OO" scale. The type "OO" would read roughly 70 on a
25 "A" material, with .030" of penetration. We offer the type "OO" in
both analog and digital models.