Date: Thu, 23 Sep 2004 22:24:10 +1200
Reply-To: Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Subject: Re: poor cornering - too much sway (tire update)
In-Reply-To: <bb0b82116929.41513647@ou.edu>
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>I agree with you that the tires are not likely the culprit, even
>though they may not be C rated. I say that
>because I've run these same wheels and tires on my 87 GL with no
>problems. So I'm thinking it must
>be suspension. However, just back in April I intstalled four brand
>new HD Bilstein shocks on the bus.
>But the new shocks did not improve cornering, they just improved the ride.
>
>I'm going to poke around the front suspension this weekend if I can
>get the time and see if anything is
>loose or broken. I'm sure the bushings are worn, because the bus
>has 223,000 miles on the chassis.
Poor-quality tires will "soggify" handling. Poor tread pattern, cheap
rubber compound, poor carcass design... lead th sidewall fles, tread
squirm and plain poor adhesion. Not to mention the wet...
To see an extreme example, try cornering hard in a Split van (T1)
with crossplies on the back... wheeee!!! Tailslides with 36hp! Try
the same vehicle with even cheap (Aquajets or equivalent) radials on
the back... what a difference!
Dampers can also make the difference. Are your Bilsteins adjustable?
Chances are they came set to the lowest rebound damping, allowing the
van to spring back upright after a corner. Try resetting them
stiffer... the van won't bob back up and will have a firmer ride.
I put Konis on my T2 (Bay) and they made a huge difference, set very
stiff. They didn't STOP bodyroll but they slowed it down (could still
pick up the inside-rear wheel in hard cornering easily enough). They
did not harm the ride. I haven't had the opportunity to drive my T3
with its new Konis, but will report on this later (though the 18"
wheels with 35%-profile tires and Whiteline swaybars will be going on
at the same time, so any report will be the result of the
combination).
Swaybars make a big difference too... try driving a 57 Oval Bug (no
swaybars as standard) and a 64 Bug (front bar standard) with the same
tires... the 57 oversteers in a straight line... frightening! The 64
is stable and can be flung around corners with abandon. The only
suspension difference is the swaybar. Situation is the same with
early & late T1s.
The 64 will oversteer when pushed hard, but not excessively... the
front swaybar controls it. Adding a rear swaybar balances things out
(so long as it's matched to the front bar!) by reducing the tendency
to understeer produced by the front bar.
>The tires are not responsible for the issue of them hitting the fender when
>you turn off a street into a driveway, etc. That is a spring issue.
Either that, or the tires are too tall or the wheels are offset far
too much outboard. Not nice to have the tire shredded...
>Or perhaps suspension bushings or ball joints. I can't believe even with
>collapsed springs the tire would hit.
My 57 Panel did... after I demolished a concrete traffic-island with
it (hit a patch of something slippery when hooning around the
corner). The torsionbar began to break-up, causing a slight sag of
the front on the driver's side... and on bumps the tire would hit the
top of the wheelwell. If a T3 has a fractured coil it could easily be
drooping... look for an obvious change in the coil angle (you'll need
to remove the wheel and then lower the brake onto a block to take the
van's full weight on the spring).
Do BOTH sides hit, or only one?
>Suspension bushings are very often
>overlooked in a quest for better handling, especially the lowers. They
>don't look or feel that bad, yet the wear is letting the lower arm move
>around quit a bit. this especially happens in rust prone climates. The
>rust forms on the inside steel sleeve of the bushing and scrubs off the
>rubber at an accelerated rate.
Hadn't thought of that, but of course if you have "variable-geometry"
suspension you'll be getting selfsteering... a bad thing if it's not
designed-in!
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<andrew.grebneff@stonebow.otago.ac.nz>
Seashell, Macintosh, VW/Toyota van nut