BzzzKill Harmonic Dampers

[S6PNJ]

A while ago I bought myself a replacement set of second-hand handlebars, after having a bike fit, on the recommendation of the fitter. Having finally got around to fitting them today, I took out the Bontrager end plugs and found some Harmonic Dampers by Mathews shoved up the inside of the bars. Having managed to get one out to see what it was all about, I then set about Googling to find some information and found them still for sale.



Does anyone have any real life experience of these and have you found them to work? Mine are aluminium but I can easily get some brass inserts made up if the heavier ones are better. I cycle mainly on chip and tar surfaced roads rather than the smooth tarmac that is much more pleasant (damn cheap council!).