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From: hakanson@orstcs.UUCP
Newsgroups: net.auto
Subject: Re: Orphaned Response - (nf)
Message-ID: <2566@hp-pcd.UUCP>
Date: Sat, 26-Nov-83 03:19:22 EST
Article-I.D.: hp-pcd.2566
Posted: Sat Nov 26 03:19:22 1983
Date-Received: Mon, 28-Nov-83 22:45:59 EST
Sender: notes_gateway@hp-pcd.UUCP
Organization: Oregon State University, Corvallis, OR
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#R:rocheste:-336700:orstcs:3000017:37777777600:2119
orstcs!hakanson    Oct 29 09:49:00 1983

I'm not an engineer, but here's what I've read:

Radials may affect the handling somewhat on older (or any) cars that have
been set up for bias-ply tires, for several reasons.  As was mentioned
earlier, they give a harsher ride, and react more quickly to road conditions,
steering input (in general, but this depends on the individual tire, of course),
so they may cause more wear in suspension and steering components.

Another thing about radials is that they have a lower rolling resistance
than bias-plies, and thus may cause a caster-change while in motion.  It
has something to do with the lower rolling resistance causing less of a
strain on the suspension, thus "pushing the alignment of the wheels back
toward the rear of the car" less than bias-ply tires.  This seemed sort of
doubtful to me, as I didn't think most cars had that much "flex" in the
suspension.  But that's what I read (I believe in Popular Science some
years back).  And remember that the caster & other front-end alignment
settings are generally arrived at through experimental modification of
an engineering estimate (especially on older production cars).  The fix
for this rolling-resistance difference is to set the caster to be "not
pushed so far toward the front," if that means anything to you.

We had an old '66 Pontiac that got switched to radials, and we didn't
know anything about changing the front alignment from factory specs, and
the thing was very twitchy -- difficult to keep going in a straight line.
This turned out to be a combination of having too much power steering,
worn & sticky ball joints, and not enough caster to give a good "center
feel" to the steering.  Of course, one sample does not a population make....

If you doubt that radials have less rolling resistance, then have you
ever wondered why people get better fuel mileage when they use radials?
I also switched a '73 Celical to radials, and had very good results --
especially a 10% improvement in gas mileage!

Marion Hakanson		{hp-pcd,teklabs}!orstcs!hakanson	(Usenet)
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