[Healeys] Shake

[Bob Spidell]

re:
"big fat and heavy wheels and tyres reduce the dampers ability to control the 
bump and rebound of the unsprung weight in the wheel/tyre/hub assembly"


On that note, do the "uprated" or "heavy duty" damper valves and/or rebuilds 
help with this?


Bob



sebring at illawarra.hotkey.net.au wrote:
> Shakes do not fall out of the sky and make your car shake. Assuming the road
> surface is reasonable the vibration is introduced by a component of the car.
> Any rotating part is a suspect. Jack the wheel at each corner and rotate it
> with a pointer aim at first the wheel rim for roundness and also
> circumferential true. Repeat the same test for the tyre surface. Even though
> perfectly balanced any out of round/true will induce a vibration. Also tyres
> as the wear change their degree of being true.If the above condition or road
> surface should induce a vibration the damper ( incorrectly referred to by many
> as a shock absorber should control this wheel movement. Remember big fat and
> heavy wheels and tyres reduce the dampers ability to control the bump and
> rebound of the unsprung weight in the wheel/tyre/hub assembly. Once the
> vibration is induced and remains undamped I believe the 612lb motor and 112lb.
> g'box assembly starts its own harmonics and rocks on/in the engine mounts.
> Softened engineer mounts exerbates this movement and excites the chassis and
> scuttle. Works cars had modifed plates on one side of the rubber block which I
> assume was to further contain the eng/g'box movements. Also works cars had
> stiffened eng. mount towers of the chassis to further limit eng/g'box raised
> above the main chassis rails


*******************************************************************
Bob Spidell           San Jose, CA            bspidell at comcast.net

*******************************************************************