Cycling in Sydney Australia
A nice sunny day in the mountains so I thought that I'd take a ride on my new bike down Victoria Pass.
All went well until I hit about 60 km/h and the bike suddenly began to violently shudder. A rhythmic shaking possibly in time with wheel rotation and as if I had a really badly unbalanced wheel. It really felt like I was about to be dumped off onto the road, but managed to pull over and stop with the wobbling continuing down to quite a slow speed. There was nothing I could find wrong with the bike and it rode nicely, afterwards, but not as fast :-)
I've done Vic Pass before on my other bike with narrow light wheels instead of big heavy mountain bike tyres going faster with no problems.
So, any suggestions as to how I can stop this happening or what's causing it? Is it just an unfortunate characteristic of the frame itself? Gotta say I'm a bit reluctant to test it again although at least this time the only vehicle behind me was ironically, an ambulance.
I'm pretty sure you are talking about side to side shaking with the front of the bike wobbling like crazy - AKA speed wobble also AKA death wobble.
Watch this poor guy at about 0:29 onwards ...
It's a resonance thing - the bike, your weight, the loading of the bike all contribute.
I've had it a few times and the way I've fixed it is by pushing one of my knees into the top tube - that changes the dynamics of the bike and changes the resonant point - the wobble stops immediately.
Huh, I normally just put more weight over the front wheel.
Had it happen a few times when I tried a shorter stem. Ended up going back to the longer one as the bike was more stable through the corners. Only a centimetre difference on the stem length but made a huge difference in handling.
and a skewer just about to do a quick release can give a nasty wheel wobble. Easy to stop, push down on your frame and re tighten. Hubs with loose bearings can sometimes give you shimmy issues.
Sounds a bit frightening, i've not experienced it (so far....).
Is there any association between the wobbles and applying the brakes? I notice in the video that it started at the entry to a bend, at a point where one might lightly tap on the brakes.
Watching the video it looks like the wobble stops as soon as he unclips.
I've experienced it on the electric bike, going about 50kph down a hill. Just gripping the bars and bracing myself against the wobble was enough to stop it.
My Dutch bike does it at 67km/h. A small bump will set it off. Maybe geometry a bit steep.