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Front wheel shaking at high speed
BY: rayd on 2010-10-25 8:52 AM
So yesterday I am riding a 20-mile out and back from my house. I've done this ride many times and there is a section with a pretty good decent where I usually top out in the high 40s, low 50s.
Yesterday I had a pretty strong headwind on the ride out, so on the decent back home I had a really good push. I was on my drops (glad I was because normally I am aero but decided on the drops because of the wind) as I was descending when suddenly my front wheel started to wobble/shake. At first I thought I flated but quickly realized that was not the case. I slowly reduced my speed and regained control of the bike. Pretty scary as I have rode this route many times but never have I had this happen before. My bike is carbon and I have heard that sometimes carbon will behave similar to this at high speeds. But odd that this has never happend before on the same bike going down the same road.
Anyone else have similar experience? -
RE: Front wheel shaking at high speed
BY: Sprint_DA on 2010-10-25 9:01 AM
I have. I had recently built my wheels, and the spokes bedded into the rim and in doing so lost tension. They were loose...like REALLY loose. It was noticeable at all speeds, though. -
RE: Front wheel shaking at high speed
BY: ratherbeswimming on 2010-10-25 9:08 AM
Might want to make sure that your front wheel is true.
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-Elaine -
RE: Front wheel shaking at high speed
BY: DanielG on 2010-10-25 9:12 AM
ratherbeswimming - 2010-10-25 10:08 AM
Might want to make sure that your front wheel is true.
Yeah, it might be out fooling around on you...
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RE: Front wheel shaking at high speed
BY: tkd.teacher on 2010-10-25 10:35 AM
rayd - 2010-10-25 6:52 AM So yesterday I am riding a 20-mile out and back from my house. I've done this ride many times and there is a section with a pretty good decent where I usually top out in the high 40s, low 50s.
Yesterday I had a pretty strong headwind on the ride out, so on the decent back home I had a really good push. I was on my drops (glad I was because normally I am aero but decided on the drops because of the wind) as I was descending when suddenly my front wheel started to wobble/shake. At first I thought I flated but quickly realized that was not the case. I slowly reduced my speed and regained control of the bike. Pretty scary as I have rode this route many times but never have I had this happen before. My bike is carbon and I have heard that sometimes carbon will behave similar to this at high speeds. But odd that this has never happend before on the same bike going down the same road.
Anyone else have similar experience?
It's just "one of those things" that happens. Almost invariably it's at high speeds, and "something" matches the frame's natural resonance, and you get a bit of a shimmy that just keeps spiraling into the death wobble.
Different tire wear, hit a small bump in the road, extra tension on the handlebars (Especially if it's cold and you are shivering), any of these can set it off.
I've experienced it twice, and it is a definite high pucker factor.
John
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RE: Front wheel shaking at high speed
BY: ditchdoc on 2010-10-25 11:07 AM
DanielG - 2010-10-25 9:12 AMratherbeswimming - 2010-10-25 10:08 AM Might want to make sure that your front wheel is true.Yeah, it might be out fooling around on you...
Especially if it's a "loose" wheel!!!
Thank you, thank you very much! Be sure and try the Veal, I'll be here all week. Don't forget to tip your waitresses and bartender!!!
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RE: Front wheel shaking at high speed
BY: rayd on 2010-10-25 1:00 PM
tkd.teacher - 2010-10-25 9:35 AMrayd - 2010-10-25 6:52 AM So yesterday I am riding a 20-mile out and back from my house. I've done this ride many times and there is a section with a pretty good decent where I usually top out in the high 40s, low 50s.
Yesterday I had a pretty strong headwind on the ride out, so on the decent back home I had a really good push. I was on my drops (glad I was because normally I am aero but decided on the drops because of the wind) as I was descending when suddenly my front wheel started to wobble/shake. At first I thought I flated but quickly realized that was not the case. I slowly reduced my speed and regained control of the bike. Pretty scary as I have rode this route many times but never have I had this happen before. My bike is carbon and I have heard that sometimes carbon will behave similar to this at high speeds. But odd that this has never happend before on the same bike going down the same road.
Anyone else have similar experience?
It's just "one of those things" that happens. Almost invariably it's at high speeds, and "something" matches the frame's natural resonance, and you get a bit of a shimmy that just keeps spiraling into the death wobble.
Different tire wear, hit a small bump in the road, extra tension on the handlebars (Especially if it's cold and you are shivering), any of these can set it off.
I've experienced it twice, and it is a definite high pucker factor.
John
Definately a "high pucker" experience! The wheel is perfectly true and the tire is fine. Hope this does not happen again anytime soon. -
RE: Front wheel shaking at high speed
BY: 1stTimeTri on 2010-10-25 1:06 PM
Read through the following thread for some info -
http://www.bikeforums.net/archive/index.php/t-637537.html -
RE: Front wheel shaking at high speed
BY: LittleCat on 2010-10-25 4:07 PM
Check your head set...also if it starts happening clamp your top tube between your knees, this can help....yeah, nothing like riding a bike at high speed that is acting like a bucking bronco. -
RE: Front wheel shaking at high speed
BY: tcovert on 2010-10-25 4:12 PM
Also check to make sure your hub is seated properly and the skewer isn't overtightened. I had a wobbling issue with a back wheel and I eventually figured out that was all it was (wheel wasn't exactly aligned with the frame).
Edited by tcovert 2010-10-25 4:12 PM
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RE: Front wheel shaking at high speed
BY: AXEL CARAVIAS on 2010-11-08 3:27 PM
Had the same problem yesterday with my carbon QR. including low 28-20mph speeds after I added a rear wing with 2 gatorade bottles and moved my seat post half inch up and half inch forward. I then also noted that the front tire had lost pressure, so I got back at low lowwww speed, the tire had 80psi so I pumped the regular 120psi get back to the road without the bottles and the shaking was gone. I shook the handles by myself trying to induce the shaking but it didn't happen again. I did a second test ride with the bottles on and it went fine. So I will think it was the low pressured front tire inducing the wobble. Anyways I will watch my speed in the downhills while I regain confidence in the bike.....just in case.
I am not sure if the half inch up made the bike more prone to wobble. It seems that it is quite easy to accidentally match the road vibration with the natural frequency of the bike, specially if you ride high on the bike
I know now the emergency procedure: a knee against the top tube, and the weight in the opposite pedal to break the harmonics... oh,,, and pray in between : )))))
FYI: I am 6'2" and riding a carbon QR size M
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RE: Front wheel shaking at high speed
BY: briderdt on 2010-11-08 3:45 PM
I had this once on my first road bike, and it scared me near to death. I learned to clamp my knees onto the top tube when descending to prevent it.
Later, I had an issue with my custom road bike in TT's. Anything over 30mph, and the front end would start the violent shimmy (while the handlebars were steady). Only happened with the front Tri-Spoke. That was an issue with a too-flexible fork. Swapped it for a Kestrel EMS fork, and it's never happened since.
As has been suggested, check the headset. Otherwise, when it happens, try changing something -- more or less weight on the front wheel, more or less grip on the handlebars, grip the top tube with your knees (do this one first).
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From this day hence... you are "keyboard warrior" -- Leegoocrap
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RE: Front wheel shaking at high speed
BY: jsselle on 2010-11-08 7:52 PM
All above is good advice. It could be the balance of the tire and tube, if they are older and getting worn. Zinn says to check the tire and tube first. Or it could be the bearings ... is it a Shimano wheel? Shimano does not usually use sealed cartridge bearings ... virtually all Shimano rims use angular contact loose ball bearings with a cone seal, which makes them roll free and very easy to maintain and overhaul, but the cone can back out/loosen and allow a shimmy in the axle. After checking/swapping the tire, this is the second thing I would check.
It could also be the headset as mentioned, earlier. Straddle your front wheel, looking towards the back of the bike ...lift up the front wheel then grab your front wheel with your knees and your handle bar with your hands ... check if there is any looseness or play in the headset mechanism ... it should turn free but you should not be able to feel any "wiggle" in the fork steerer.And yeah, like rayd and flaming skull john says above, sometimes I get a resonance wobble that goes away.
And last ... It's probably NOT the wheel magnet.... but if all else fails, and your magnet it located on the wheel near the same point on the circumference as the valve stem, the weight of the valve stem plus the magnet together could cause a heavy spot and possibly contribute to a wobble. If you lift the front wheel off the ground, then spin the wheel and it keeps rolling to a stop with the same location and the bottom, this indicates a heavy spot in the wheel that could contribute to a wobble, especially at higher speeds. (I don't know if the math and physics would care about a ten gram wheel magnet ... but as a habit I always locate my wheel magnet 180 degrees out from the valve stem.) But it is probably not the magnet.
Edited by jsselle 2010-11-08 7:58 PM
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RE: Front wheel shaking at high speed
BY: AdventureBear on 2010-11-09 2:40 AM
Sprint_DA - 2010-10-25 8:01 AM
I have. I had recently built my wheels, and the spokes bedded into the rim and in doing so lost tension. They were loose...like REALLY loose. It was noticeable at all speeds, though.
Sometimes this happens because the opposite end of the spokes at teh hub side are not adequately set in. YOu can fix this during the wheel build itself by using a small nail punch and tapping the head of each spoke to set it firmly into the hub, reducing the likihood of the spokes loosening as you start to ride and the wheel settles.j
I used this method for a single speed mtn bike wheel build over 3 years ago and have only had to true the wheel once after about 2 years of use.
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Coach of World and National Champion Triathlete, Kirsten Sass
Fresh Freestyle: 99 Practices for Triathletes & Swimmers
http://wp.me/P2tUAV-xc -
RE: Front wheel shaking at high speed
BY: scottuf on 2011-02-16 8:04 PM
today i rode my hilliest ride ever - buckhill and sugarloaf near clermont for those interested. after struggling to the top of sugarloaf and resting to take in the view and catch my breath, i began my decent. just coasting, as i hit about 30 mph the bike started wobbling like crazy, probably the closest i've ever come to crashing. i hit the brakes hard and came to a stop, checked the tires, headset, etc, and no obvious problems. took it easy the rest of the ride and had my LBS check it out. no problems and he said it happens every now and then with no obvious cause. i wonder if the cross winds had something to do with it?
scary scary scary!!! -
RE: Front wheel shaking at high speed
BY: jkron on 2011-02-16 9:03 PM
It has happened to me twice, once during a race and it was a miracle I didn't crash. I asked these same questions in this forum in 2006 and got the same answers, so I did some research...
Google: "death wobble" - "bicycle death wobble" or "bicycle speed wobble".
Generally it's not the tightness of your components, it's the bad luck of the physics between you and your bike and the conditions. There are any number of conditions, when matched just right, will create the phenomenon.
It's not the same for everyone, and good luck with solving it. The hard part is getting back on that hill and recreating the scenario so you can "practice" dealing with it.
I've never solved it with my tri bike and it has cost me in races when I'm on the brakes while folks are zipping past me.
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RE: Front wheel shaking at high speed
BY: strates on 2011-02-17 3:32 AM
The only solution is to go faster. -
RE: Front wheel shaking at high speed
BY: Jon bovi on 2011-02-17 7:57 AM
A couple years ago it would happen to me all the time for about a two or three month period. The first time was at the end of a ride and I was less then a mile from home. I have to go down a short yet steep hill where my speed can hit 50-60k an hour as long as there's no head wind. People in the cars behind don't seem to realize how fast someone on a bike can go so they always try to pass me on this stretch. The road is narrow, high curbs and it curves in a kinda of a S bend so it's a stupid place to pass a cyclist. So one day going down the hill doing just over 50k/hr (and the speed limit is only 50k) a pick up trys to pass with traffic going the opposite direction. He realizes he can't do it so instead of dropping back he for whatever reason drives right beside me for a good ten seconds leaving me with no more then a two feet between the curb and his truck. Scared the crap out of me and next thing you know the front of my bike is shaking like crazy. I came within inches of the curb and hitting it and getting run over. When I get home I tried to figure out what was wrong with my bike but found nothing. So a few days later I go out again and going down that hill it starts to shake. The next day it shakes going down another hill, wtf? I go on here and other forums and they all say check your wheel, check your headset, stem's to high, too short. I knew none of these were the issue because I had just got my new Trek Madone and it was happening with it aswell. But, I came across a couple articles on "death wobbles" which talked about how the rider causes alot of them. In my case whenever I was about to go down a hill at high speed I had already convinced myself that the bike was going to shake, that would make me nervous, my arms would start to shake just a weeeeee bit and that started a wobble. How did I solve it? I told myself "chill out". Squeezing the top tube with my knees and peddling down hill also helped.
That's my story.
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RE: Front wheel shaking at high speed
BY: scottuf on 2011-02-17 8:02 AM
Jon bovi - 2011-02-17 8:57 AM A couple years ago it would happen to me all the time for about a two or three month period. The first time was at the end of a ride and I was less then a mile from home. I have to go down a short yet steep hill where my speed can hit 50-60k an hour as long as there's no head wind. People in the cars behind don't seem to realize how fast someone on a bike can go so they always try to pass me on this stretch. The road is narrow, high curbs and it curves in a kinda of a S bend so it's a stupid place to pass a cyclist. So one day going down the hill doing just over 50k/hr (and the speed limit is only 50k) a pick up trys to pass with traffic going the opposite direction. He realizes he can't do it so instead of dropping back he for whatever reason drives right beside me for a good ten seconds leaving me with no more then a two feet between the curb and his truck. Scared the crap out of me and next thing you know the front of my bike is shaking like crazy. I came within inches of the curb and hitting it and getting run over. When I get home I tried to figure out what was wrong with my bike but found nothing. So a few days later I go out again and going down that hill it starts to shake. The next day it shakes going down another hill, wtf? I go on here and other forums and they all say check your wheel, check your headset, stem's to high, too short. I knew none of these were the issue because I had just got my new Trek Madone and it was happening with it aswell. But, I came across a couple articles on "death wobbles" which talked about how the rider causes alot of them. In my case whenever I was about to go down a hill at high speed I had already convinced myself that the bike was going to shake, that would make me nervous, my arms would start to shake just a weeeeee bit and that started a wobble. How did I solve it? I told myself "chill out". Squeezing the top tube with my knees and peddling down hill also helped. That's my story.
Man glad you didn't wreck in that situation. What a jerk.
Google leads me to believe that I was probably holding the handlebars a bit to tightly and that lead to the problem. Going down a 11% grade for the first time was a bit intimidating.