Date:         Sun, 12 Jul 2015 08:28:00 -0700
Reply-To:     Don Hanson <dhanson928@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Don Hanson <dhanson928@GMAIL.COM>
Subject:      Re: Why new tires should go on the rear.
In-Reply-To:  <CABToOYLpR8oB=21Dgxgg=-nxyh_cwr8mcycBWf+wKmQ9RPoUEA@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

>
> >
> >
> http://blog.allstate.com/new-tires-rear/?cid=CSY-PB-ZM-AB-outbrain_com:New-T
> > ires-To-The-Rear
> >
> > The driver drove through the track with the new tires on the rear and let
> > the front tires hydroplane. This is an easy recovery, just back off the
> > gas.
>
>
 Not so fast (pun unintended).....In a rear-engined vehicle, catching a
slide from the rear wheels isn't always that simple or easy...especially if
the slide has gone unnoticed by the driver for too long, and "too long"
isn't that long (a fraction of a second) in a rear-engined vehicle...

.Consider that there is a big lump of mass (the whole motor)  back there,
beyond the rear tires. Once that mass begins swinging around, rotating the
vehicle with the help of centrifugal force, letting off the gas AND
steering into the slide doesn't work as well as it does with a
front-engined vehicle....When you lift your foot, the vehicle decelerates,
and some  of the traction (grip to the road) that you already don't have
enough of at the rear, that grip is transferred to the front tires (just
like stomping on the brakes, but of course, we never do that during a
slide, do we?)...Exactly what you DON'T need, that added traction at the
front tires and the subtracted traction from the rear, as the vehicle rocks
forward on it's suspension........

Steering into the skid IS the best hope of saving it from a spin....but
letting off, dropping throttle,  during a slide, that's usually when the
driver has the experience he later describes something like...."Geeze, I
thought I had it saved, but all of a sudden, it, like,....snapped around on
me, and I hit the ditch backwards......"  The older rear-engined Porsche
race cars were notorious for this kinda handling...they took a lot of
learning to make them go fast around a road-course.  "Slow in-fast out" was
their mantra (so that a slide never had the chance to start and
decelerating while cornering was never called for).   Those rear engined
cars also came from the factory with much bigger rear tires to help control
their  tendency to oversteer..(rear end lets loose first)

  Of course, a total over-simplification.

  For those who are interested in learning how the vehicle behaves, you
might want to  find a safe venue and safely induce some of the
situations..safe. safe.. and don't tip over your Vanagon...
.I learned really a lot about my vehicles on a formal "skid-pad" at a race
track...a great big paved area where one vehicle a time was allowed to
circle around  at what ever speed you wanted...experimenting with full
throttle, brakes, steering, etc...I also learned a lot living and driving
various vehicles in the mountains of the West on snow covered roads...some
of the lessons were expensive...

   Me?  I put new rubber onto my front wheels if everything else is
equal...Not for traction but more to reduce the  chances of an explosive
tire deflation and the chances of dropping the vehicle onto the wheel rim
during a dicey traffic or terrain situation...

  (disclaimer) YMMV and this is my internet opinion only...

DHanson


Then the driver hammered through the track with the new tires on the front,

> > throwing the car into a spin. This was impossible to recover from.
> >
> > Reality is "normal driving" where your back tires break loose and you
> steer
> > into the slide & regain traction.
> >
> > No thanks - I'll continue mounting new tires on the front.
>