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Speed wobbles
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On a long ride the other day I was accelerating down a steepish descent when I suddenly developed speed wobbles at 75kph. They felt like they were getting very severe so I gently applied to brakes to pull below 60. I am not sure why this happened because I have been this speed before with no worries.

I did notice that I had lost a bidon out of my seat carrier and we speculated that perhaps there was a slight imbalance in drag passing over my lower back through the bottle cage.

FOr the record I was riding a 2001 TCR Aero with a Thomson fast forward post. I had the original bars on and was down in the drops with face basically on the stem. I've ridden this bike with my race carbon x's on at 90kph and felt fine (although a little wary as I hadn't ridden that speed before). There was no wind factor.

Any suggestions?
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Re: Speed wobbles [mv2005] [ In reply to ]
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Try tightening the headset. It needs to be tighter than you may think.
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Re: Speed wobbles [mv2005] [ In reply to ]
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I've experienced this. Hug the top bar with your knees and take some of the weight off the seat. Explained somewhat here. http://www.pro-am.com.au/...ble_on_a_bicycle.htm
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Re: Speed wobbles [cerveloguy] [ In reply to ]
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if all else fails change the fork and add some rake to it. say going from 43 to 44 or 45 degrees

Brian Stover USAT LII
Accelerate3 Coaching
Insta

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Re: Speed wobbles [mv2005] [ In reply to ]
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Strangely enough, I had the same thing thing happen yesterday on the Slowtwitch Mt. Palomar ride. Three of us were sorta racing the descent and I was in this position(I forget what it's called):



All of a sudden, I got the wobbles. I remembered reading something about grasping the top tube between between your thighs so I did this and it went away. I'll check my headset today.
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Re: Speed wobbles [jaylew] [ In reply to ]
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I also got the speed wobbles going down Palomar Mt.

It was so cold that my shaking body transmitted it to the bike.

Chuck
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Re: Speed wobbles [Chuck M] [ In reply to ]
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Oddly enough, I've experienced speed wobbles coming down Palomar Mt. also. I think it has a lot to do with shaking from the cold, maybe slight unevenness in the pavement, because it is such a steep downgrade - maybe from even slight braking, and/or a combination of all three.

I have also found that turing the rims, side to side AND roundness (very time consuming and the tire must be off the rim) helps eliminate speed wobbles .
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Re: Speed wobbles [tom] [ In reply to ]
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Your headset should be as loose as possible with no play. Overtightening the headset to have friction provide any steering damping will reduce headset life. I've had bikes that wobble and bikes that don't. Given the same care, conditions and speed, even the bikes that wobbled wouldn't do it always.

The constructive interference that builds creating the shake is a weird one and may be a combination of countless factors. Knees on the top tube and butt of the saddle seem to quell them the best.

-SD

https://www.kickstarter.com/...bike-for-the-new-era
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