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Back in August in this space, the subject was speed wobble, which if you aren’t familiar with the term is the tendency of a bike usually traveling downhill to suddenly start shaking violently. The front end (front wheel and handlebars) start swinging side to side and may do so faster and faster. Worse, with some speed wobbles (also called high speed shimmy), nothing you can do will stop it.
To read more about the phenomenon, ways to deal with it if it happens and ways to stop it, go back and read the previous Tech Talk: https://www.roadbikerider.com/avoiding-bicycle-speed-wobble/. Be sure to read the comments, which contain many helpful tips. And, also, read part 2 of the story, which summarizes the best solutions for dealing with speed wobble: https://www.roadbikerider.com/comprehensive-list-speed-wobble-causes/.
If you’ve ever experienced speed wobble you know how scary it is even if you don’t crash because of it. And, if you have, you’ll probably be as interested as I am in Cane Creek’s new headset designed to stop speed wobble called the Hellbender 70 Visco.
Cane Creek already proved the technology for electric bikes with their ViscoSet. E-bikes can have step-through frames that are too flexible and prone to wobbling. Sometimes their batteries are located on rear racks, the worst place for the extra weight, which creates a tail wagging the dog effect and potentially awful speed wobble. So if the ViscoSet solved these issues, Cane Creek should have a winning new product.
I think it’s only fair to point out that bicycles designed correctly – and this includes e-bikes – should NOT wobble. You would expect every bike to be built and spec’d with proper performance in mind and even tested for things such as any tendency to speed wobble. But, unfortunately, some bikes make it to market that haven’t been tested enough or properly.
The Visco is a new headset designed for most regular bicycles. The ingenious features that stop the wobbles look like multiple tabbed washers. The tabs fit in keyways inside the headset. Cane Creek calls the washers damping plates and says that they have a viscous grease between them. This results in a damping action that is enough to stifle speed wobbles.
I haven’t seen one or used one yet but I’ve ridden plenty of other Cane Creek headsets and gotten excellent performance out of them. Price is $99.99 – $119.99 depending on which model is needed.
Of interest is that most of Cane Creek’s marketing does not specifically mention that the Hellbender 70 Visco is for road bikes that speed wobble. They say that it’s for “cargo bikes, commuter bikes, children’s bikes, gravel bikes, bikepacking bikes, and even an occasional mountain bike.” This is strange because as you’ll see if you go back and read the previous Tech Talks on speed wobble, roadies have been dealing with it the longest.
The fact that they do state that it’s for gravel bikes should mean that some of the models will fit modern road bikes. At this point I have a lot more to learn about it. I only have one bike that wobbles and it’s an oldie but goodie with a 1-inch threaded headset. I doubt this new headset will fit.
But, if I get a chance to test the Hellbender – perhaps on a booth bike at the Sea Otter in April (if Cane Creek attends), I’ll let you know. In the meantime, even if they don’t currently make a model that fits that wobbling road bike you might like to fix (like mine), I still think it’s great that they have invented something that might be available at some point in the future. Let’s hope it’s soon.
To learn more, here’s Cane Creek’s video introduction to the Hellbender 70 Visco headset:
Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s cycling streak ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.
That is basically a friction type steering damper that came on many motorcycles before hydraulic dampers became more popular. The difference is these are non adjustable whereas the motorcycle dampers usually ad a knob to adjust damping. This could work on some applications???
I had a 1967 Harley-Davidson Sprint (made in Italy) that had a knob-adjustable steering damper.
Roller bearing type headsets like the Tange Needle Blaster (sp?) do a good job of reducing shimmy.
On a beauty day in S WVa I’m riding my Suzuki sport bike at 50mph and Bambi came out of the L ditch so fast that I didn’t have time to do anything right or wrong. Took off my L mirror and put me in a “tank slapper “, lock to lock. I did my best and didn’t go down. Don’t give up the ship but if you need a shimmy damper on your bicycle at high speeds, you either need to go slower or you need a new bike IMHO.
I’m sure on inexpensive bikes that are not designed well, or have poor weight distribution,, front wheel wobble is inherent, as these bikes are not meant to go downhill fast. I have a custom Serotta built as a crit bike with Columbus XLS tubing. At. speeds over 30mph the front end has a slight wobble. I found if I lift my butt off the saddle it puts the weight on the bottom bracket instead of the weight being a rear bias which tends to make the front wheel light.
Interesting headset. I noticed on the Cane Creek website that the headset uses a fluorocarbon gel to dampen, how many years will this gel last before the headset would stop dampening?
The other issue is cold weather which will make the gel hard thus the dampening would be made ineffective, wouldn’t it?
(Responding to post by Fred, on Thurs evening 19 Jan,)
(1) I too wonder about the durability of the viscous stuff, and also whether it can ooze out and let things dry up.
(2) About low temperature, and stiffening the damping medium: Interesting subject, because this can work two ways depending on how a mechanism is configured. In the viscous-headset case, I’d say no, the damping would become even more effective, only trouble is that it might disable not only the shimmy but to some degree the steering. Kind of like if you stiffened the fluid in your car shock absorbers, they’d damp your suspension travel even more effectively, but perhaps too well, so that your axles might as well be bolted to your chassis. Either way, of course, I’d hope that Cane Creek would have picked a compound whose viscosity is relatively insensitive to temperature.
The alternative configuration, where locking up the damping medium does free up the shimmy, is one that’s hard for me to visualize a version of that would apply to a headset, but here’s an illustration of the principle: Suppose you had a pogo stick and on the end of its “foot” you stacked a shock absorber. Now if you still want your pogo stick to be bouncy, you have to really stiffen up the shock absorber. The softer you make the viscosity in the shock absorber, the more it shorts out the bounciness of the spring on top of it. (I’m avoiding the terms “series” and “parallel” because that distinction tends to work in opposite ways when applied to mechanical systems versus electrical circuits — if you call my end-to-end mounting of the shock and the pogo stick “series,” then that’s dynamically equivalent to an electrical resistor in parallel with a capacitor: for the capacitor to stay “bouncy,” the resistor has to have a high resistance so as not to short the capacitor out. I had a system-dynamics teacher who called this scheme a “shunt-throttled” junction, the resistor branch being a shunt past the capacitor.)
I guess that if you wanted a headset scenario of this configuration, the following would be kind of reaching, but here’s what I can offer: suppose you installed a torsion spring on your steering axis (even though I’d take a dim view of doing that). Now if you mounted the frame’s side of that torsion spring to the rotary damper instead of to the frame, THEN the damper would damp the steering when it was soft and not when it was stiffened up.
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