Date: Wed, 21 Mar 2007 08:10:48 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Tire Choice Question (long piggy-back question)
Content-Type: text/plain; format=flowed
The "AT" is an open tread all terrain type tire and is somewhat taller than
the LTX's up front. This creates 2 problems. First, the open tread design
actually pprovides less contact patch for street driving and it does not
provide the directional stability of a straight rib. Thus the van requires
more steering correction to travel striaght. The slightly raised rear also
throughs off the front Caster adjustment making the front end more sensitive
to steering input. What you are experiencing is over steer each time you
make a correction. If you swap the thires front/rear, you will feel the
unudersteer and it will be driveable agian.
This effect you are feeling is why tire manufactureres now recomend 4 snows
on 2wd applications.
A whel alignment with a proper caster adjustment should corect most of that
over steer. Better yet, bring the caster angle up to say 7-8 degrees. It
will want to go straight. If you want some off road or snow capabilies, get
a matched set of 4 tires. If you do mostly highway driving, get a set of
good highway tires.
Dennis
>From: Don Hanson <dhanson@GORGE.NET>
>Reply-To: Don Hanson <dhanson@GORGE.NET>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Re: Tire Choice Question (long piggy-back question)
>Date: Tue, 20 Mar 2007 22:51:19 -0400
>
>Not sure of list protocol about tacking-onto another thread with a
>related question so if this is not customary, let me know..For now, a tire
>question/opinions wanted for a dilema I created late last fall for my own
>self.
>
> My rear tires were getting worn and not behaving in my slick driveway in
>late Dec. so I had to get some replacments quickly. The only available
>tires I found in the appropriate size and specs were at Les Schwabs, since
>I live in a fairly small town..So, I took all the specs from the fronts
>that were still at about 1/2+ tread life and went to the tire shop for a
>match..Fronts are Michelin LTX M+S in 195 75. The load range is C and they
>have two Poly, two steel plys in the tread and two poly in the sidewalls.
>
> Ok, the tire tech shows me some Wildcat LTs, M/S. Same size, same
>configuration, same ply configuration, same load range..I think, "Ok,
>everything matches, should work OK, guess I will go for em" and I have em
>installed...Pick up the van and I notice the new tires are a little taller
>and slightly narrower..Hmm..Check the sizes and they are
>right..think.."Different brand..must be that"
>
> But the van is now really disconcerting to drive...
>
> I expected some difference in handling, what with two brands of tires,
>end for end, so I figured I would get used to it eventually. Nope! The
>front feels like it 'over turns' and the back feels like it wants to keep
>going to the outside of turns after the front is done steering..Hard to put
>into words for non-race drivers, but it is really sensitive on "turn-in"
>and the rear seems to "wallow" a bit rather than settle into a turn. With
>the Michelins on all four corners, I loved the way this van handled..With
>the miss-matched mix, it sucks! I often must cross a steel grated
>bridgedeck, and man, is that scary! You can not predict which direction
>the van will dart next, what with it 'hunting' all over the place following
>the decking ridges...
>
> So the question is: What would you all do to get the van feeling great
>again? My option seems to be to get the same brand tires all around. I
>should have known this, being a club car racer, but I thought.."Sheesh,
>this is a VW van, not a racecar, and all the numbers and ratings match on
>these tires, should be 'good enough' for highway speeds in a van....NOT!"
>
> So, would you go with another pair of Wildcats from Schwab or spring the
>big bucks for 4 new top of the line tires? Money is a consideration here,
>as is the fact that Schwab has service shops all over the West, where I
>mostly travel, and they are very good about service and warrantees..My
>Michelin fronts are ready for replacement soon, while the new Wildcats have
>maybe 500 miles only.
>
> So, if I go to four of the Wildcats, which seem to have less rigid
>sidewalls than the Michelins, would that make the car feel balanced again,
>or would both ends just feel "mushy" and make me hate driving it? Are the
>Michelins that much stiffer, even though they are built with the same
>configuration? Would I just still want the Michelins after trying the four
>Wildcats, or would I get used to the slightly less rigid sidewall flex,
>enough to justify the money savings of only getting an additional two new
>tires? I am guessing the handling will become more predictable and normal
>feeling when I do match brands, end for end, again.
>
> I have done lots of pressure experimenting and taken tread temps (like at
>the racetrack) but no matter what I do, it feels like I am driving two vans
>at one time...Ugg.
> Suggestions, opinions?
> Thanks, Don Hanson
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