Subject: Re: [Shop-talk] Fw: Axle ratio?

From: David Hillman <[email-masked]>
Date: Mon, 13 Apr 2015 17:57:44 -0400 (EDT)

On Mon, 13 Apr 2015, [email-masked] wrote:
> Because they aren't competing in how fast they can stop, but how fast they
> can go.  8>)

    So you are suggesting that weight only positively effects traction used 
to stop, not used to go or turn?  How does the weight know when "turn off" 
and "turn on"?  That's obviously not possible.  If weight improves braking 
traction, it has to also improve traction in all other phases.

    If weight were beneficial overall, racecars would be as heavy as 
practical... especially ones with excess horsepower.

    They are not.

    Also, that link discusses the relative stopping distances of loaded v 
unloaded semis with trailers.  And much of it focuses on staying in 
control, not actual stopping distances.  That's more than a little 
different than the original claim, which was a "heavy load" behind a 
truck stopping quicker, versus the truck alone.  That is a no contest. 
Especially if we are talking about pickup type trucks.

    According to pickuptrucks.com, my F150 will stop in 132 feet from 
60mph.  Other half-tons are between 137 (GMC) and 150 (Toyota).  In 
order to match that while towing my 20' box ( ~7,000 lbs loaded ), I'd 
have to stop in ~8 car-lengths (nose to tail).  To beat it, I'd have to 
approach -1G.  I have had a couple emergency stops, and that is not 
happening.  Not even with a brand new trailer.

<http://special-reports.pickuptrucks.com/2013/06/2013-light-duty-challenge-braking.html>

--
  David Hillman
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