Vehicle Mirror Vibrations!

I have been legally driving for almost 50 years now, in a lot of cars and road surfaces and cannot recall any mirror vibration that troubled me.

If this vibration is in the vanity sun-visor mirror for the passenger tell her not to be that vain or install an optic stabilizer.

GA. factory-installed mirrors *never* vibrate at the car's normal oscillatory range.

If you've already got a manufactured vehicle, you don't decide any natural frequencies - they're inherent in the material properties and geometry of every component. You don't want the mirrors to vibrate at any operational RPM - bear in mind that considering the baseline engine RPM in vibrational analysis is not sufficient, because of the complex nature of vehicles with thousands of components, some of which are producing vibrations at multiples of the crank/flywheel RPM.

see the below link for a very similar CR4 discussion.

http://cr4.globalspec.com/thread/40427/Mirror-Vibration-and-Engine-RPMs

Regards,

TinTin

Is it the mirror that is the problem or the choice of mounting locations? I have yet to see a mirror vibrate on any of the vehicles i have driven unless it was broken or an after market installation. The after market installation that vibrated had been attached to car panels. The extra hung weight of the mirror on the panel causing it to flex more.

I observe blurred images at 1200-1400rpm.This is what i term as vibrations at natural frequency.

now i want to shift this band so that i dont observe any vibrations in my range!

Where is the mirror mounted?

Write to Harley-Davidson in Milwaukee Wisconsin.

Follow a Harley and look at its mirror. there is a reason why after 30 years on a Harley some people call it quits and buy a Honda.

Oh wait, thats your own mirror your talking about.

Try different magnets in different locations to try and change the frequency. Or, if magnets won't "stick", try securing a range of weights with a spring clamp or tape. If you hit something that works find a suitable object and epoxy it in place.

Without going into modal analysis or knowing the details of your problem, I think it's safe to say that by making the mirror and its mounting system as stiff and low mass as possible, you will raise its lowest resonant frequency to be higher than any frequency your vehicle can produce. An example of such a mirror design is the "Autobahn" mirror that you can Google and purchase at reasonable cost.