Date:         Mon, 19 Apr 2010 20:39:08 -0700
Reply-To:     John Bange <jbange@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Bange <jbange@GMAIL.COM>
Subject:      Re: Why go to big tires?
In-Reply-To:  <s2m1250b1e91004192005jdb489ea5y8fac7f7e0f8028da@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

>
> I understand the oversimplification, but surely the rotating mass (and
> placement thereof) contributes a small portion of the overall stopping force
> needed to stop a 4000lb vehicle? Or does it? If one assumes the rotating
> mass is at the perimeter (worst case), what percentage of the overall force
> are we looking at? I'm guessing it will be less than 10%... anyone care to
> do the math with some typical figures? :-)
>
>
I'm sure there's some difference, but without spinning up a stock tire on a
normal wheel and a big tire on a 16 and then stopping them with a torque
gauge attached, I can't imagine HOW you'd get an accurate measurement. I
have no doubt the brakes are inadequate with the big wheels/tires--- they
were inadequate with the stock ones! Still, it's not so much worse that I'd
say it's dangerous. I've already made one panic stop in the last month, and
it locks 'em up just the same. Compared to my '67 Dart with 4 wheel
non-power drums, they're top notch.

I do have the Volks Cafe big brake kit too. I just haven't decided if I'm
going to trick out this beater* van or maybe hold out for a better one.

* It's a SoCal beater. Minor oil leak, a few dents, bad carpet, no major
rust. The kind of Vanagon people on the east coast would kill for.

--
John Bange