Speed Wobble Fix, why I switched bars & stem

This video describes the results of my experiment with narrower bars and shorter stem than I’ve ever used, and the effect had upon the known already congenitally twitchiness of super light frames.

Speed wobble is a high frequency oscillation caused by, well, that’s a point of some debate, and a lot of research, but classic conditions for a speed wobble are high speeds (over 50kph), going downhill, while coasting. Any sort of a “disturbance” of the bikes stable resonant frequency can induce wobble: too tight the grip on the bars, an uneven road surface, the rider sneezes! It’s unpredictable.

Here’s a link to a very good article that discusses the phenomenon.

https://cyclingtips.com/2020/07/bicyc...

Reading about “Hopf Bifurcation” could also be interesting.

In any case, I eliminated speed wobble in my Yoeleo R11 by simply changing the steering arc from a small degree arc, quick steering cockpit, to a larger arc, and slower steering one, i.e. I replaced 40cm bars, 90mm stem with wider bars and longer stem. I also decided to switch out the shorter stack lower headset bearing (I had changed to a 7mm from the Yoeleo spec 8mm), just to be safe, and the problem disappeared. Im not sure the bearing had much if any to do with the problem, but the supposed improved aesthetics the 7mm added was not important.

Yoeleo R11 is a SL frame, it moves underneath you a bit; you can feel it jump around. It’s not unique to Yoeleo; more so a characteristic of such frames.