- [Dan] Speed wobble is one of the most frightening things that can happen to you
when you're out on a ride. Hopefully, you have never experienced it before,
but if you have, it's something you are never going to forget.
Now, a lot of you have written to us recently asking what causes it,
and also what you should do if it does happen to you.
Now, speed wobble is pretty much exactly what it says. It is a violent and
almost uncontrollable oscillation from side to side of your frame and fork,
which often occurs at very high speeds. Well, we did manage to get out of that
one. Well done, Si.
- [Simon] Quite a close run thing. Now, unfortunately, I'm pleased to be able to
say that we actually haven't experienced speed wobble ourselves for many many
years, but nevertheless, we've been doing our research.
- Nobody can be 100% sure as to exactly what causes speed wobble,
however, there are a few theories out there at the moment, and the first of
those is that your bike is not quite up to scratch. So maybe the two wheels aren't
perfectly aligned, so at a certain point, they effectively begin to fight against
each other, a little bit like you get in a car with badly-aligned wheels,
where the steering wheel starts to shake at a certain speed.
- Now, related to this is the possibility that actually the front end of your
bike, or more specifically, the top tube, just isn't stiff enough.
Now, that's something that's going to be felt more keenly by heavier riders,
or those of us that perhaps might sit with too much weight over the back of the bike,
so not enough weight over the front wheel. And in those cases,
it's actually the front of the bike that's then going to try and rotate or pivot
around the seat tube, so where your center of mass is. Now, it has to be said that
modern bikes do tend to be much stiffer than those from the olden days,
and so they are less prone intrinsically to speed wobble.
- Apparently, though, the initiation of speed wobble can actually be down to the
rider themselves. So maybe on a cold descent, a little bit like we've got
today, you start to shake and shiver ever so slightly, and that can start it.
Or it might be that your pedaling style or upper body is slightly more wobbly than
most, so what can happen is you might lend a bike to someone, having never
experienced speed wobble yourself, but they actually might get it.
- Added in to this is also the fact that the size of your bike,
and also the geometry of it, can also have an effect as well.
So something that we've learned from our friends in the world of motorbiking,
who suffer from speed wobble far worse than us, is the head tube angle and also
the trail if the bike is really important. So, bikes with a steeper head angle
actually feel more twitchy and then suffer from speed wobble far, far worse.
- And also, the farther above the main frame of the bike your weight is,
apparently the more likely you are to get speed wobble. So if you've got quite a
small frame size for your height, and you got a lot of seat pins sticking out,
maybe a load of headset spaces here, and even an upward-turning stem,
you're going to have more flex and more chance of speed wobble.
- And finally, riding no-handed, and therefore having little or no weight at
the front end of the bike is also a potential cause of speed wobble,
especially if you're going at high speeds. Now, we wouldn't recommend going no-handed
at the best of times going down a descent, but especially not if you're prone to a
bit of speed wobble.
- Okay, then, those are the probable causes of speed wobble. Perhaps most
importantly, though, what do you actually do if you experience it?
Bearing in mind it could actually get so bad that it throws you off your bike,
which is, let's face it, the last thing you want to happen at high speed.
- Or at slower speed, I guess, as well. One of the first things that you could
think about is your weight distribution, which you should try and keep centered on
your bike, and lower your body weight down towards the frame. Some people have also
reported success in elevating themselves ever so slightly off the saddle,
whilst gripping the top tube with their knees.
- Yeah, and then a slightly different method, still raising yourself off of the
saddle slightly, is then to drop your A pedal to the 6:00 position,
and then put your body weight through there. The theory behind that is that that
stops the seat tube of your bike from becoming the pivot that we talked about
earlier on, and then hopefully, stabilizing your bike.
- Also try and think about your arms and hands, which should be fairly relaxed,
which is not going to be something that you instinctively think of having once you
experience speed wobble. So, hold on to the bars on the drops here,
but not with a vise-like grip, try and keep your hands fairly relaxed,
and allow your arms to give the whole system a bit of suspension.
- Undoubtedly, one of the first things that's going to go through your mind as
you start to experience speed wobble is a strong desire to slow down,
and fortunately, that is actually the right thing to do. However,
what you don't want to do is jam both brakes on really suddenly.
Instead, you want to apply your rear brake only, and very gradually,
so that you start to scrub off speed, and then ultimately, come to a complete stop.
- Now, hopefully, this video will have helped you address some of the issues
which can be causing your speed wobble in the first place, or at least,
help you to get out of it if you do experience it out on your ride.
However, we'd love to hear your own experiences with speed wobble,
any possible solutions that you could have for us and our viewers,
too. You can leave those in the comment section just down below.
In the meantime, we've got a couple more videos which we think might be relevant
for you right now. In the top, just up there, is how to improve your descending.
- Yeah, or for a little bit more information about the geometry of your
bike, including head angle, trail, and so forth, then click just down there.
- And to subscribe to the Global Cycling Network, all you've got to do
is click on the globe.
- I hope viewers' experiences are largely going to be positive, like,
not "I had this horrible crash," more like, "Oof,
you wouldn't believe what I did to get out of speed wobble."
- "Yeah. Did a wheelie."
- Fingers crossed.