– [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.