04-24-2018, 01:08 AM
(04-23-2018, 03:26 AM)egleaves_imp Wrote: Had a little scare this morning on the way to work. As I’m approaching my freeway exit I get over with plenty of time and fall in line with other traffic slowing for the exit. We had collectively slowed to around 50mph when my bike went into a violent wobble that must have lasted 2 or 3 seconds. My feet were thrown of off the pegs and the rear started alternately beating the insides of my legs while the bars whipped back and forth. I thought for sure I was going down, but I kept my cool and reacted without panicking. My legs are killing me, but I kept the bike up.
Speeds were about 50mph and slowing gently, no hard braking, no known road obstacles. It felt like the rear brake was locked up for the whole wobble. Riding the last mile to work felt odd every time I applied the rear brake….once I parked the bike I found that the rear brake lever is bent up and out which drastically changed its position relative to my foot. That’s why things felt different.
Could that lever have been bent (out and up) by my leg smashing into the side of the bike? It wasn't like that when I left the house. Think I can just step on it to bend it back, or would I be putting weird stress on other components that I can’t see?
I'm still trying to replay the whole thing in my head in the hope that I can determine the cause of the wobble. The bike has never done that, and aside from cars ahead and behind me conditions were pretty favorable.
I am trying to think on the causes:
-worn tyre means smaller tyre radiuis, so smaller steering trail.
-braking means bike dives, so lower trail too.
Still, I'd say this would mean the bike isn't as stable as it could be, but is that enough to cause a tank slapper... :-? I wouldn't think so!
Check your pressures (again: affect your tyre radius->steering trail), and check your suspension preload settings (rake -nose down attitude- will decrease trail too).
And, if you find the root cause, please let us know!