Date:         Thu, 1 Jun 2006 08:29:13 -0700
Reply-To:     John Bange <jbange@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Bange <jbange@GMAIL.COM>
Subject:      Re: Tire Rotation
Comments: To: Mike Miller <mwmiller@cwnet.com>
In-Reply-To:  <C0A43CB7.E48C%mwmiller@cwnet.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

>
> Has anyone gotten information from tire MANUFACTURORS about whether radial
> tires can be rotated side to side, i.e. Change directions?


Yes. The old saw about never switching sides with radial tires is kinda old
news. When radial tires were first produced, the accuracy of the molding
process was not so good. As a result, there was a certain degree of
imbalanced "slack" to the reinforcement that would "tighten up" in one
direction after a period of use. Flipping the tire to rotate the other way
would shift the process the other way, flexing the material of the tire.
This flexing could substantially weaken the tire. Nowadays, the molding
process produces such a tight, evenly balanced tire that changing rotation
in no problem.

If you consult the tire manufacturers' web sites, the ones that say anything
about tire rotation either defer to the owner's manual of the car, or simply
ask you whether you have a front wheel, rear wheel, or all wheel drive, and
then recommend whichever 4-wheel rotation is appropriate. Since it's
nigh-impossible to find a NON-radial consumer car tire in use nowadays, it's
pretty safe to say rotation change is a non-issue as far as the manufacturer
is concerned.

It is worth noting that the TREAD PATTERN on some tires is directional, and
these tires should be rotated only back-to-front, front-to-back. Tires of
this type are always clearly marked on the sidewall with ROTATION ----->, or
<----- ROTATION, the arrow pointing (hopefully) towards the front of the
vehicle when the word is at the top of the tire. It's definitely Bad Luck to
drive with directional tires turning the wrong way. It turns an excellent
water-shedding tire like the Michelin HydroEdge into a water-COLLECTING,
hydroplaning, rotating water-ski.

Also, the usual issues with viscous coupler strain from variable tire sizes
appiles to 4WD's.

--
John Bange
'90 Vanagon - "Geldsauger"