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Re: Front Wheel Vibration

To: George Gerth <ggerth@west.net>
Subject: Re: Front Wheel Vibration
From: steve@tap.csiro.au (Steve Moore)
Date: Fri, 11 Apr 1997 11:03:49 +1000
George Girth wrote,


>Does anyone REALLY know why the Factory recommended such low pressures
>on the +4?  Was it for balanced handling?  Ride comfort?  I know that
>the steering effort is very high at those low pressures!  I usually run
>at higher pressures (25-30) and the ride is rough, but the car rolls so
>much easier.
>
>What pressures are being run at Autocrosses/Vintage races?
>
>Geo.
>63 +4
>66 DB5

The low tyre (tire) pressures are almost certainly for ride comfort. With a
set of decent shock absorbers on the rear you can run 30psi pressure and
still have reasonable ride (for a Morgan that is). I run 30 psi on the road
and 35psi+ on the track. The car is fitted with adjustable gas shocks on
the rear. Most of the (in)famous ride characteristics of Morgan's are
attributable to the rear suspension, which you are virtually sitting on,
rather than the front end which is a relatively long way from where you
feel the bumps!

As far as the front end wobbles go, it seems that if anything at all is
amiss with the front end an harmonic vibration accurs at 50-55mph. Check
the damper blades and shock mounts, play in the steering box, the tubes
that run from the bottom of the kigpins diagonally back to the chassis, as
well as kingpin bush wear and front wheel bearings, wheel balance and while
your at it check if the wheels themselves are true. Have I forgotten
something?

That should keep you busy for the weekend.

Cheers

Steve Moore

Dr. Stephen Moore
CSIRO Tropical Agriculture
Molecular Animal Genetics Centre
Level 3, Gehrmann Laboratories
University of Queensland
St. Lucia, 4072
Australia

ph  61 7 3377 0476
fax 61 7 3377 0480



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