Date: Tue, 16 Mar 2010 14:55:41 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Revs per mile , was: 15" VS. 16' WHEELS
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for sure, to take all factors into account...
you'd have to consider the speed...( tires expand some with higher speeds )
I noticed that one company says revs per mile at 45 mph. - that makes good
sense.
and tire pressure.
and ambient temps too, both air and road surface.
not to mention tire tread wear.
Heck, even the amount of time the tire has been running, as temp will
increase with time driving, in fairly warm condtions -that matters.
And you should consider if air or nitrogen is used to inflate the tire. (
nitrogen expands less with heat than air )
Heck again ..
even the humidity of the air in the tire would factor in, if you are really
getting down to the nitty gritty of it.
for a basic reference point and for comparing tires ........I'm thinking
going with the manfucturerer's data is probably best overall.
I also like the idea of marking off say 100 feet, or 200 ....
drive slowly, count how many times the tire rotates ....use that info to get
how many revolutions it would make in a mile...
and even then ...given the factors above ....things could vary a few % this
way or that way.
I think just stick with what the manufacturer says ...
and it probaly even vaires a tiny bit from batch to batch of tire
production, and year to year for the exact same tire.
Varies with the political climate of where the rubber comes from even.
Hey, as long as they feel good, last well, do what they are supposed to do
and you like 'em ..
that's what mainly counts !
"my tires do more revs per miles than yours do ......na na, na na " ....lol
! :-)
----- Original Message -----
From: "mark drillock" <mdrillock@COX.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, March 16, 2010 2:28 PM
Subject: Re: Revs per mile , was: 15" VS. 16' WHEELS
> You can look up any number of manufacturers rev/mile for a given size.
> You will find they tend to group together in a range and then you will
> see that the Miata Tire Toy program calculates a value for that size
> that falls outside of that group. You could say that none of the tire
> companies can count or measure but I would say the Miata Tire Toy
> program makes erroneous assumptions and then gives false results.
>
> Also, axle center to ground distance is a poor way to measure tires for
> revs/mile purposes as inflation pressure affects that static measurement
> to an extent that greatly exceeds its effect on true revs/mile while
> rotating.
>
>
> Mark
>
>
> John Bange wrote:
>
>>
>> I would love to trust the manufacturer's quoted numbers, but when the
>> Revs
>> per Mils and the diameter they state don't match, it's hard to take them
>> completely seriously. I suspect they might use the largest possible
>> diameter, and the smallest possible rolling radius. Given that, I tend to
>> use the mathematical number initially, and then actual physical
>> measurement
>> after they're on the vehicle (axle center to ground, and GPS mileage vs
>> miles clocked that assume 805 RPM).
>>
>> --
>> John Bange
>>
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