Speed wobble

[Friend]

Does anyone have suggestions for correcting a wobble I get when I ride with no hands?

[Steve Palincsar]

Reminds me of a Henny Youngman joke:  The patient says, "Doctor, it hurts when I do this." "Then don't do that!"

Or you could try clamping the top tube between your knees.

On 3/23/20 10:01 PM, Friend wrote:

Does anyone have suggestions for correcting a wobble I get when I ride with no hands?

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Steve Palincsar
Alexandria, Virginia 
USA

[Kainalu V. -Brooklyn NY]

Put your hands back on!
Otherwise there's expensive needle bearinged headsets that can help. I swapped out the headset on my Clem and noticed a difference in no handed stability. Unscientific, but it seems to work. I switched due to need, and that a friend had a good used one to try, not to fix that lovely wiggle when no handing. But yeah, less wiggle for sure with that new headset.
-Kai

[Kainalu V. -Brooklyn NY]

Knee against the toptube is free, and also helps heaps.
-Kai

[Peter White]

I did an experiment some years ago. A customer was complaining about the bike having a shimmy after he moved his saddle to the rear for a better fit. He also kept a racktop bag filled with all sorts of stuff. This got me to thinking, a state which is fraught with danger.

On my own touring bike, which also had a racktop bag, I put a case of 10 SRAM chains at the rear of the bag and filled up the front with a light jacket to keep the chains at the rear. My bike shimmied badly. I stopped and moved the chains to the front and put the jacket at the rear. No more shimmy. I then vowed never to carry that many chains at the rear of my racktop bag again.

Anyway, weight distribution does seem to contribute to the problem. It's interesting that large racing frames seem to be more inclined to shimmy than small frames. And if you look at the position of the saddle relative to the two hubs it's going to be much closer to the rear than on a small frame, so the weight distribution is further to the rear.

PJW

On Mon, Mar 23, 2020 at 10:01 PM Friend <jtp...@gmail.com> wrote:

Does anyone have suggestions for correcting a wobble I get when I ride with no hands?

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Peter White

[Dave Small]

Hi Peter,

Was your racktop bag on a front rack or a rear rack, and what kind of bike was it (I'm thinking about trail with that latter question).  Thanks.

Dave

Boston/Indy

[Peter White]

A rear rack on a Peter Mooney 58cm touring frame. Frame designed for low rider front rack, not the 30 lbs in front of the steering axis routine.

PJW

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Peter White

[James Copp]

I thought it was likely weight distribution.  I ride with my saddle pretty far back and if I cary anything, then it's in a saddle bag.

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[James Copp]

That's a great question.  I'll make sure that they are.

On Wed, Mar 25, 2020 at 9:48 PM Fryett <fry...@gmail.com> wrote:

Are you wheels perfectly aligned within the frame?

On Monday, March 23, 2020 at 7:01:24 PM UTC-7, Friend wrote:

Does anyone have suggestions for correcting a wobble I get when I ride with no hands?

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[dougP]

My experience has been that it's weight distribution problem.  I had a Hobo Baggins bag as a saddle bag, with the usual load'o'crap; tools, tubes, lock, etc.  I would occasionally get shimmy going downhill.  Moving the Hobo to the handlebars solved the problem.

I also experimented with weight in 4 panniers after encountering some shimmy while touring.  Using books as ballast, and my shimmy inducing downhill as a control, I discovered that things were rock solid with 60% of the weight on the front.  Since then, If I'm only doing a 2 bag trip (lodging or an overnight) I put the bags on the front.

dougP

On Monday, March 23, 2020 at 7:01:24 PM UTC-7, Friend wrote:

[Jonathan D.]

My Toyo Atlantis did this. I switched this headset and that helped. The Riv site mentions this as welll in the description. https://www.rivbike.com/products/headset-tange-ird-needl-blastr-roller-drive

[dougP]

Mine is a 58 cm Toyo.  A couple of years later, I needed a headset & went with one of the Tange needle bearings that Riv sold.  No problems.

dougP

[Peter White]

I've never found that wheel alignment, which is actually frame alignment, has any effect on wobble. If the frame is out of alignment the two wheels will not follow the same line when the bike is moving in a straight line. For example, if the rear wheel is tracking to the right of the front wheel when moving in a straight line, the bike will tend to turn towards the right. This is easiest to feel when riding no hands. But this won't cause the bike to wobble.

Peter White

On Wed, Mar 25, 2020 at 9:48 PM Fryett <fry...@gmail.com> wrote:

Are you wheels perfectly aligned within the frame?

On Monday, March 23, 2020 at 7:01:24 PM UTC-7, Friend wrote:

Does anyone have suggestions for correcting a wobble I get when I ride with no hands?

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Peter White

[Cyclofiend Jim]

Yeah. That is my experience as well. 

Mostly it's about the weight between fore/aft. 

They tend to be speed-specific. They'll happen at 18 mph, but not at 17, for example.

Jobst wrote some (fairly strongly opinionated) missives about this - this came up first: https://www.sheldonbrown.com/brandt/shimmy.html

The only time I've had a wobble was one brevet on the Hilsen, in which I'd aft-loaded 2x the amount of planned gear due to a weather change, had nothing on the front, and sat up as I crested a hill and glided no handed. 

Got a wiggle-wiggle-wiggle and shifted forward slightly, at which point it stopped. I never managed to reproduce it with more mindful loading.

Ride buddy JimG had a long struggle with his Kogswell on this topic - he had documented it well, which ought to be searchable through his site - http://yojimg.net/bike/  

Jim / cyclofiend

On Thursday, March 26, 2020 at 4:46:49 AM UTC-7, Peter White wrote:

I've never found that wheel alignment, which is actually frame alignment, has any effect on wobble. If the frame is out of alignment the two wheels will not follow the same line when the bike is moving in a straight line. For example, if the rear wheel is tracking to the right of the front wheel when moving in a straight line, the bike will tend to turn towards the right. This is easiest to feel when riding no hands. But this won't cause the bike to wobble.

Peter White

On Wed, Mar 25, 2020 at 9:48 PM Fryett <fry...@gmail.com> wrote:

Are you wheels perfectly aligned within the frame?

On Monday, March 23, 2020 at 7:01:24 PM UTC-7, Friend wrote:

Does anyone have suggestions for correcting a wobble I get when I ride with no hands?

-- 

--

Peter White

[lambbo]

Dearest Friend, 

Is this happening on the used Homer you bought or the new-from-riv Appaloosa?   I bought my Cheviot used on this list, and it got speed wobble at certain speeds down hills.  Later, I got in an accident and bought a new fork from Rivendell, and the bike no longer wobbles.  I don't know if it was that I re-installed the fork and messed with the headset, or if it was the new fork.   

Good luck! 

[Friend]

This is happening on the Homer.  It has a large saddle bag but when I was riding yesterday, with maybe 5 or 7 pounds on the rear rack, it still had wobble going about 12mph.  I did buy it used but it's the factory fork.  I think it may also have something to do with the handlebars.  They are albastache on a dirt drop stem so they are pretty high off the steering column.  

[Sean on Bike]

I had the same issue with my Hilsen when using a brevet bag with very moderate weight and rack. I since no longer use that set up but shimmy persisted. 

The culprit ended up being the tires–my beloved Jack Brown greens. Bike shop said tires vary in how "true" they're manufactured–to use my own terminology, some manufacturers being better than other. Ever since, I've been riding Schwalbe Marathon Supremes and Continental Grand Prix 4's and shimmy's gone away. 

Jus' sayin'.

Sean in Eden Prairie

[Friend]

Interesting.  I ride Antelope Hills.

[brendonoid]

Tighten the headset a bit. Maybe more than you should. Always works.

Weight distribution is a factor but not a cause.