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-   -   First speed wobble crash (https://www.bikeforums.net/showthread.php?t=1211902)

blakcloud 09-01-20 04:03 PM

First speed wobble crash
 
Today I experienced a shimmy that I couldn't control. I went for a ride today and twenty minutes in I was descending a hill at 56 km and then in no time I am skidding along the pavement. The shimmy turned into a full out wobble that I just couldn't get under control.

Two weeks ago I experienced shimmy at 82 km an hour and I was able to slow the bike down and control it. I had a smaller one a few days ago at about 70 km/h. Today's was much slower but I had hit some rough pavement that may have contributed to the wobble.

Did I help contribute to this mishap, you bet I did. I didn't grab the top tube between my legs, I didn't raise my weight above the saddle or loosen my grip on the bars. These are all solutions but they are counter-intuitive when it is happening. I was hanging on for dear life, just trying to slow the bike down. I think I need to start training for this to make sure it doesn't happen again. I have done a lot of reading on speed wobble and one thing is clear, there is no definitive answer. Different solutions work for different people and the solutions are not universal. My biggest obstacle will be fear. The fear to go downhill fast again.

This is just a narrative of what happened. I was one of the unlucky ones that couldn't control today's shimmy.

The bike was the Trek Domane SL6 that is one year old exactly today.

WhyFi 09-01-20 04:06 PM

Oof - sorry to hear. Any notable damage to you or the bike? While we're at it - which bike was it?

BoraxKid 09-01-20 04:17 PM

If you are repeatedly experiencing some wobble at different speeds, I would start by checking your hubs to make sure they are stable. And then I would check your wheels for trueness. If this is a relatively new phenomenon, it sounds like something has changed on your bike. If this has been going on for a long time on your bike, then I would question why you waited so long to address the issue.

Sorg67 09-01-20 04:21 PM

Thanks for sharing. I learned a little. Maybe help me if I face a similar challenge.

blakcloud 09-01-20 04:21 PM


Originally Posted by WhyFi (Post 21672889)
Oof - sorry to hear. Any notable damage to you or the bike? While we're at it - which bike was it?

Thanks. I added the bike to the original post. It was my Trek Domane SL6. Unfortunately I laid it down on the drive side so there is that typical damage. I haven't gone over the bike in fine detail to see if there is any serious carbon damage, that will happen in a few days when I am feeling better. Did some damage to my ankle, knee, elbow, shoulder and the palm of my hand. A few days of rest and ice should take care of it.

Voodoo76 09-01-20 04:27 PM

Best of luck, really, it can become a real mental issue. Not to be a downer but I've been searching for the answer to this for 4 years with minimal success, get a handle on it asap. 45 years on the road, always considered a very good bike handler. Never regained confidence. But I can still crush it on the flats.

shelbyfv 09-01-20 04:28 PM

Can you give details as to how you fell? Did the front wheel get sideways and send you over the bars or did both wheels slide out and drop you to the side or what?

WhyFi 09-01-20 04:28 PM


Originally Posted by blakcloud (Post 21672916)
Thanks. I added the bike to the original post. It was my Trek Domane SL6. Unfortunately I laid it down on the drive side so there is that typical damage. I haven't gone over the bike in fine detail to see if there is any serious carbon damage, that will happen in a few days when I am feeling better. Did some damage to my ankle, knee, elbow, shoulder and the palm of my hand. A few days of rest and ice should take care of it.

Could have been worse!

And it's interesting that it was the Domane. I had the same frame, a 2018 SL5 GRVL, and it was so, so stable.

MoAlpha 09-01-20 04:33 PM

Hope you and the bike are okay. That really sucks.

I have experienced lots of wobbles, mainly when I'm cold, shivering, and losing partial control of my stiffening muscles. Brute-forcing myself to relax my arms and shoulders is what has helped me stay rubber side down and, yes, it's a big psychological thing. Just remember you're part of the mechanical system that's oscillating and anything you can do to stop putting energy into it will help. To wit, try to relax in addition to the other helpful actions you cite.

esskay1000 09-01-20 05:43 PM

Man, sorry to hear that. I've experienced high speed wobble about 6 or 7 times and it can be terrifying. For me it's only happened when I'm going very fast downhill (usually over 40mph) and there's a strong headwind. Those conditions were present every single time. Fortunately I never went down and was able to come to a stop but the wobble would persist all the way down until I was going maybe 12mph or slower.

By any chance are you tall, with a large bike frame? I talked to some pro racers about it, including the famous Ron Kiefel of the 7-11 Team from the 1980's, and many said it's more common with tall riders and larger frames. I'm 6'4", and ride a 61cm frame. And two of my buddies who have experienced it are also pretty tall. Just wondering.

zatopek 09-01-20 05:46 PM

Sorry you had that experience. Glad you seem to be OK. I had a Coppi steel frame that I loved. However, it wobbled on high speed descents (40 plus mph) too frequently for my comfort. I was always able to regain control by doing what you alluded to - knees gripping top tube, up off the saddle and loosen the arms and shoulders - but I got to where I feared descending on it. That was enough for me to strip it to build a bike on another frame and retire the old girl. Knock on wood, none of my bikes since, have had any similar problems. Good luck. Stay safe.

Pizzaiolo Americano 09-01-20 05:57 PM


Originally Posted by blakcloud (Post 21672881)
Today I experienced a shimmy that I couldn't control. I went for a ride today and twenty minutes in I was descending a hill at 56 km and then in no time I am skidding along the pavement. The shimmy turned into a full out wobble that I just couldn't get under control.

Two weeks ago I experienced shimmy at 82 km an hour and I was able to slow the bike down and control it. I had a smaller one a few days ago at about 70 km/h. Today's was much slower but I had hit some rough pavement that may have contributed to the wobble.

Did I help contribute to this mishap, you bet I did. I didn't grab the top tube between my legs, I didn't raise my weight above the saddle or loosen my grip on the bars. These are all solutions but they are counter-intuitive when it is happening. I was hanging on for dear life, just trying to slow the bike down. I think I need to start training for this to make sure it doesn't happen again. I have done a lot of reading on speed wobble and one thing is clear, there is no definitive answer. Different solutions work for different people and the solutions are not universal. My biggest obstacle will be fear. The fear to go downhill fast again.

This is just a narrative of what happened. I was one of the unlucky ones that couldn't control today's shimmy.

The bike was the Trek Domane SL6 that is one year old exactly today.

Ensure your headset is properly tensioned. That will definitely cause a wobble...

noodle soup 09-01-20 07:52 PM


Originally Posted by blakcloud (Post 21672916)
Did some damage to my ankle, knee, elbow, shoulder and the palm of my hand. A few days of rest and ice should take care of it.

were you wearing gloves?

No marks on your helmet? sounds like you were lucky.

BTW, Honey and Tegaderm is great on road rash.

noodle soup 09-01-20 07:56 PM


Originally Posted by WhyFi (Post 21672927)
it's interesting that it was the Domane. I had the same frame, a 2018 SL5 GRVL, and it was so, so stable.

+1

I've owned many many bikes in my life, and have never ridden a road bike that was as stable/predictable at high speed.

Beach Bob 09-01-20 08:27 PM

I've had a couple of good speed wobbles in my life... absolutely terrifying when they occur. First time was at 80 km on a mountain descent; thankfully the roads were still closed to vehicles so I managed to get it under control after a couple of KMs. Second one was at about 60km on a descent and I managed to hit the handle bar when moving up from the drops. Was able to remember everything I'd read after the first one and had a lot less drama.

For those that have never experiences the thrill https://cyclingtips.com/2020/07/bicy...-to-stop-them/ gives a good description of what's happening and how to try to get it all back (interesting note...ANYTHING with a single connection the the steering wheels can have the same thing happen; Jeep Wranglers were notorious for it)

PS: Glad OP seems to be relatively OK from the experience; not sure I would be as cool about it as s/he

79pmooney 09-01-20 08:38 PM

My best bike has issues if I am not completely relaxed and "going for it" I have a fast, near straight 1000' descent. I try to remember to bring extra clothing and put it on at the top (a state park at the summit). Being warm helps me a lot.

Ben

August West 09-01-20 09:02 PM

I'll be interested to see if you can determine the cause. I had a 2019 SL6 which was replaced it in Feb. with a 2020 SLR7 and have never had a hint of wobble on either. And I have literally hundreds of decents between them with a min of 60 kph and up to a high of 96 kph on every decent.

diphthong 09-01-20 09:06 PM


Originally Posted by esskay1000 (Post 21673041)
Man, sorry to hear that. I've experienced high speed wobble about 6 or 7 times and it can be terrifying. For me it's only happened when I'm going very fast downhill (usually over 40mph) and there's a strong headwind. Those conditions were present every single time. Fortunately I never went down and was able to come to a stop but the wobble would persist all the way down until I was going maybe 12mph or slower.

By any chance are you tall, with a large bike frame? I talked to some pro racers about it, including the famous Ron Kiefel of the 7-11 Team from the 1980's, and many said it's more common with tall riders and larger frames. I'm 6'4", and ride a 61cm frame. And two of my buddies who have experienced it are also pretty tall. Just wondering.

terrifying about the same number of times and persisting until < 10 mph like you but seems to have always occurred on a decent grade + significant crosswind. i ride a few frames from 58-60cm.

rousseau 09-01-20 10:32 PM

At 0:28...fugging hell...


rousseau 09-01-20 10:35 PM


Interestingly, speed wobbles only seem to happen when a rider is coasting. This is because shimmy happens in a system that’s in a state of equilibrium and pedalling has the effect of throwing off that equilibrium.

https://cyclingtips.com/2020/07/bicy...-to-stop-them/


Does this mean that you should start pedalling when you get into a speed wobble?

NoWhammies 09-01-20 10:45 PM

Yikes! Thanks for sharing your story and the tips. Glad to hear you and the bike escaped relatively unscathed. Hope you're able to get back out on your bike soon.

Seattle Forrest 09-02-20 12:10 AM


Originally Posted by esskay1000 (Post 21673041)
Man, sorry to hear that. I've experienced high speed wobble about 6 or 7 times and it can be terrifying. For me it's only happened when I'm going very fast downhill (usually over 40mph) and there's a strong headwind. Those conditions were present every single time. Fortunately I never went down and was able to come to a stop but the wobble would persist all the way down until I was going maybe 12mph or slower.

By any chance are you tall, with a large bike frame? I talked to some pro racers about it, including the famous Ron Kiefel of the 7-11 Team from the 1980's, and many said it's more common with tall riders and larger frames. I'm 6'4", and ride a 61cm frame. And two of my buddies who have experienced it are also pretty tall. Just wondering.

I'm 6'1" and ride a 58. Haven't experienced a speed wobble in many years and several bikes ago.

blakcloud 09-02-20 06:53 AM


Originally Posted by shelbyfv (Post 21672924)
Can you give details as to how you fell? Did the front wheel get sideways and send you over the bars or did both wheels slide out and drop you to the side or what?

Both wheels slid out and I landed on my right side. I veered into the oncoming lane because I could not get the bike under control. Lucky for me no cars were coming as it is usually a very busy roadway.


Originally Posted by Voodoo76 (Post 21672923)
Best of luck, really, it can become a real mental issue. Not to be a downer but I've been searching for the answer to this for 4 years with minimal success, get a handle on it asap. 45 years on the road, always considered a very good bike handler. Never regained confidence. But I can still crush it on the flats.

That is what I am afraid of overcoming the mental issue.


Originally Posted by esskay1000 (Post 21673041)
Man, sorry to hear that. I've experienced high speed wobble about 6 or 7 times and it can be terrifying. For me it's only happened when I'm going very fast downhill (usually over 40mph) and there's a strong headwind. Those conditions were present every single time. Fortunately I never went down and was able to come to a stop but the wobble would persist all the way down until I was going maybe 12mph or slower.

By any chance are you tall, with a large bike frame? I talked to some pro racers about it, including the famous Ron Kiefel of the 7-11 Team from the 1980's, and many said it's more common with tall riders and larger frames. I'm 6'4", and ride a 61cm frame. And two of my buddies who have experienced it are also pretty tall. Just wondering.

No, I am not tall 5' 8" (173 cm) tall. The bike is a 54 cm. I had read about speed wobble over the years and how some taller bikes were more prone to it.


Originally Posted by rousseau (Post 21673414)
At 0:28...fugging hell...
Video snipped

That is pretty close to what happened to me. You can see in the video that he has a difficult time getting the bike to the shoulder of the road but he does manage.

Thanks to everyone for their comments and or concerns. I will go over the bike and check the likely culprits and make sure there isn't any damage to the carbon.

55murray 09-02-20 07:12 AM

Bummer, I have heard about this but it has never happened to me on any bike ever, not even crappy cruisers I've taken down hills at 40mph plus. Road bikes around 50mph.

MinnMan 09-02-20 09:38 AM

I just don't think that I'd have the guts to "relax" my grip if I were experiencing that. So, what to do? Move the knees inward, try to pedal, and what about the upper body? Probably if I'm going that fast, I'm already down and tucked. And no brakes, I assume, however tempting?


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