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-   -   fear and wobble on descents (https://www.bikeforums.net/road-cycling/558122-fear-wobble-descents.html)

Randallissimo 07-02-09 08:55 PM

fear and wobble on descents
 
I used to try to go as fast as I could on downhills ever since I was young. But last year I had a couple of scary episodes where I was convinced I was going to be thrown off the bike on 25mph+ descents because the bike wobbled so hard. Now I'm spooked.

The first time was a high speed violent wobble on a new bike with an adjustable stem. Rattled my teeth it shook so hard. We swapped out the stem, and made some adjustments, and it was fine for 150 miles. Then in traffic I got nerved up going 25mph on a bumpy shoulder, and it did it again. But this time it wasn't the hard rattle, it was a slower, deeper wobble that very nearly tossed me. Scared the crap out of me.

This year I have a Lemond carbon bike. But I still have the wobbles and then the fear coming down hills. Last weekend I was riding with a buddy in his neighborhood, rural, hilly and small mountains. Not only did I get owned and sapped on the climbs, but got I really scared a couple of times on some 35 mph descents to the point where I wobbled and got spooked enough to attempt to slow down, which just made matters worse.

Now I think I have a case of the self fulfilling prophesies. I think, uh-oh... and then I can't relax, and sure enough that bike goes all squirrelly. I know I am supposed to relax and not grip too hard, and also put a knee to the top tube. These things help a little, but not enough. Also, I think I may have too long of a stem, putting me too far forward. Would this contribute?

What I have read is telling me I probably am tensing up my upper body and transmitting input to the frame and bars. But how can I correct this? Maybe it's just a mental thing?

NathanC 07-02-09 08:59 PM

25-35mph isn't very fast...

swebb75ky 07-02-09 09:28 PM

I'm not very experienced...maybe 2000 miles under me, with no particular "fast descent" bent to me...but:

a) I routinely break 30 miles per hour (as in, on almost every ride)
b) have never had a hint of wobble -- certainly nothing that was remotely scary
c) haven't been riding anything particularly "high performance" ($1100 steel LeMond)

I can't really offer any advice, but what you are describing doesn't really sound "normal" to me. If it were, I don't know that I would still be riding.

-Steve

DScott 07-02-09 09:35 PM

You can do this.

My noob advice: you have to relax. Go as slowly as you need to in order to stay relaxed, then gradually add speed. Relax. Ride in the drops, keep a loose grip on the bars/hands near the brakes, knees to top tube, and relax. Add speed when you can do the descent relaxed. Relax. Picture yourself doing the descent calm, cool, collected, and in good form. Breathe easily, and relax.

Did I point out you need to relax yet? ;)

Search here and google 'speed wobble' for more than you ever thought possible on the subject. You can do this.

Strong Bad 07-02-09 09:48 PM

I'm guessing this has more to do with the bikes you are (were) riding than you. Some bikes do get speed wobble due to a number of things. It can be caused by a misaligned frame, a flexible frame, a flexible fork, a bad head angle/ fork rake combination, a loose or pitted headset. It can be accentuated by a number of things, like all of those previous factors in combination, and flexible wheels, nervous or cold shivering rider input. Some bikes just get speed wobble.
I have had speed wobble twice. Once I discovered a crack in the downtube on my frame (some hundreds of miles later), and the other time it was a combination of cross winds, high profile low spoke count wheels, and me shivering from the cold. Don't let it get you down. Fix anything you can find that may have contributed to the problem, and keep on riding and descending until you get your confidence back.

rmwun54 07-02-09 10:04 PM

I've had a high speed wobble once and that was because of a deep dish aero rim that I had while riding through a cross wind at speed. So I got rid of the rim and only use semi-aero rims instead and haven't had that problem since, and I still ride down steep roads at speed.

MAK 07-02-09 10:45 PM

I read an article about this somewhere.

If at a high speed the bike starts to vibrate and wobble, clamp your knees or thighs against the top tube for a few seconds and the vibration will quickly stop. It has to do with interrupting a wavelength or something.

On BRAG last month there was a 7 1/2 mile downhill and at 42 mph I had to use this technique and it did the trick.

Good luck.

msincredible 07-02-09 11:25 PM

Tense arms/upper body will definitely magnify any wobbles.

Sounds like you need to practice good descending technique (which isn't always "going as fast as you can" ;)) on some easier (less sloped) downhills.

dmann 07-02-09 11:30 PM

Most wobbles are compounded by the riders attempt to dampen the vibration. Lighten up on the death grip, relax your arms and back, take several deep breaths and slowly rotate the crank. These techniques will serve to occupy your mind and body and will effectively reduce if not eliminate the induced wobble. Owned a 1979 Kawaski 1000 LTD, @ 105mph you had to float your hands off the grips to eliminate the wobble, then you could twist the throttle full open and bury the needle >150mphs!

Element GT 07-02-09 11:53 PM

think about puppies.

AEO 07-02-09 11:59 PM

death wobble, possible on all inline two wheeled vehicles.

25mph isn't very fast, but the key is to shift weight so that the center of gravity changes location.
be it knees clasping top tube or lifting butt off of saddle

bumperm 07-03-09 12:42 AM

Besides the advice already given to clamp your knees against the top tube, put your weight on the pedals by lifting your weight off the seat to unload it. Brake gently to slow the bike.

kenji51590 07-03-09 12:51 AM


Originally Posted by DScott (Post 9211437)
You can do this.

My noob advice: you have to relax. Go as slowly as you need to in order to stay relaxed, then gradually add speed. Relax. Ride in the drops, keep a loose grip on the bars/hands near the brakes, knees to top tube, and relax. Add speed when you can do the descent relaxed. Relax. Picture yourself doing the descent calm, cool, collected, and in good form. Breathe easily, and relax.

Did I point out you need to relax yet? ;)

Search here and google 'speed wobble' for more than you ever thought possible on the subject. You can do this.

I have this same problem haha i get scared because i just started road cycling but your advice is what im doing.. going slow and increasing slowly too.. but i have a question what are drops and descents lol? Excuse my noob level I'm not yet familiar with the terminology :/

icyclist 07-03-09 01:14 AM

>I think, uh-oh... and then I can't relax, and sure enough that bike goes all squirrelly. <

Yes - as you realize, it's in your head. Just keep practicing. It's like anything that involves a skill - you need to hone it. Pick an easy descent, do it a few times, do a few more on a longer steeper hill, and you won't experience the wobbles.

It's the same as if you were a weakling starting out to climb hills. You'd get stronger. It's the same with descents. You'll build more confidence the more you descent. Asking for some secret solution here won't help - riding your bike will. :thumb:

>I know I am supposed to relax and not grip too hard, and also put a knee to the top tube.<

Just practice coasting downhill over and over again until descending is second nature. (And you'll become a lot stronger in the process).

Good luck.

Steev 07-03-09 03:44 AM

I know you said it has happened on different bikes, but a loose headset can cause this. Perhaps you need to change how you set up headset preload.

cyclezealot 07-03-09 04:11 AM

I've always had a near phobia of heights. But, ever since I hit a small pebble on a descent and resulted in a torn shoulder ligament- that was the topper.And shoulder surgery , from which I've never totally recovered... I'm the last one down.. Thanks my club are seemingly willing to wait. A chance for my cycling friends to Break out the power bars.

guadzilla 07-03-09 04:25 AM

Try a tip from mountain biking - slide your butt a little backwards and get into the MTB "attack position" (body bent at the waist, elbows bent, cranks level, knees bent, slightly out of saddle).

This will feel a little more stable and should help you relax a bit, as you get used to the speed. Then once you are comfy, you can go back to a more roadie position.

V.

patentcad 07-03-09 04:49 AM

Oh relax.

gabdy 07-03-09 04:56 AM

I'm OK on descents, but I do get fear and loathing from BF.

nitropowered 07-03-09 06:58 AM

Have a friend ride the bike to see if its the bike or you.

I've only had one bike wobble on me, and that was when I was descending at 35-40mph and took my hands off the bars to get a gel. As long as I didn't take my hands off the bars at 35-40mph, the bike was fine.

Eljimberino 07-03-09 07:10 AM

Thicker tyres, 100psi, way back in the seat. Also, having a rider in front of you helps get a better idea of whats ahead.

ericm979 07-03-09 08:55 AM

Since it's happened on two different bikes, it is not anything about the bike, it is you. You have to relax. It's easier to relax if you have proper form.

#1 Make sure you elbows are bent. If they are locked you make a rigid connection to the bike and the feedback loop is what causes the wobble. Yes, that means that you need to lean forward. I check to see if I am relaxed by trying to flap my elbows like a chicken. On a straight, not in the middle of a turn.

#2 descend in the drops, not on the hoods. Braking and steering are both better from the drops.

#3. Keep your forearms and hands relaxed. You should be able to wiggle your fingers. Ride with one or two fingers on the brakes, don't use your whole hand and make a death grip on the bars.

#4 Keep your head up and look all the way down the road, as far as you can see. Focusing too close gives you less time to react and makes your speed seem much greater. If you look up the road you will have more time to react and everything will seem slower.

#5 don't ride the brakes. Brake for turns or periodically if you need to slow down, then let off and let them cool.



Find a nice low traffic descent that isn't too steep and practice. Work on relaxing, on your form, and on picking a line and riding it (useful for descents with turns). Don't worry about going fast, you can do that later once you have improved your form and learned to relax.

ridethecliche 07-03-09 09:08 AM

What kind of bike do you ride?

On my steel frame with steel fork, I freak out on descents. I don't remember my bad crash, but I wouldn't be surprised if high speed shimmy and fork instability had something do with it.

My caad9 corners like nobody's business. I haven't ever had shimmy on it, and I've hit close to 50 mph while cornering in a descent and had absolutely no give.

Luddite 07-03-09 09:34 AM

Going downhill freaks me out, too, and I've never wobbled...

Randallissimo 07-03-09 10:51 AM

I know 25 - 35mph isn't very fast, so I shouldn't call it a high speed wobble. It's just a wobble. I know about avoiding a death grip and relaxing. I try to position myself back on the saddle. I think my form is actually not that bad. But yet, when it starts to go I get nervous and probably make it worse until I don't feel like I have control and need to slow way down.

My bike is a Lemond carbon Zurich with a Ritchey carbon fork and Shimano wheels with DA hubs.


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