[RBW] Re: Toyo Atlantis Shimmy ???

2016-09-26 Thread Evan Baird 
In 100% of shimmy incidents it's down to Huldufólk distribution.

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-09-17 Thread 'Tony McG' via RBW Owners Bunch 
Wednesday night I was riding with the local club road ride and I sat up and 
let go of the bars at about 19 mph, and the bars wobbled like crazy. Today 
I was riding gravel at about 15 mph, and there wasn't a hint of shimmy when 
I sat up and let go of the bars. I ride lower tire pressure on gravel than 
pavement, so I think I will watch it closer if the new parts don't cure the 
problem. I ordered an IRD RollerDrive headset from Soma and it will replace 
the current headset as soon as my Fargo is back on the road.

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-29 Thread masmojo 
Having a bunch of spacers is probably contributing to the headset coming loose 
issue, but it should not be causing a shimmy. I do agree that sometimes over 
tighting fan be worse than too loose; too tight & thebearing races can get 
dimpled, once this happens, you will basically have indexed steering and riding 
no hands will be, difficult if not impossible.

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-27 Thread Lungimsam 
Don't fret over it.
80$ Tange RollerDrive + 40$ LBS install+10minutes wait while they do it = 
you are all set. 

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-27 Thread iamkeith 
Tony,

I think I may retract some of what I've said above.  I always stress out 
about being an arm-chair mechanic and giving bad advice so, once I've said 
something, I keep going over it in my head and thinking about how I might 
have been wrong.  In this case, I think the added shim is NOT where I 
thought it might be from looking your picture.

I just took a look at my daughter's bike which has the same headset.   
Here's a shot from a slightly different angle than yours, which shows the 
race fully inserted into the headtube.   Viewed from the angle of your 
photo, it does give the appearance of there being a "gap," which I took to 
be a spacer.

So, if they had to add a spacer in order to be able to  tighten the 
locknut, what I'm now thinking is simply that the upper lip of the locknut 
was contacting the top of the steerer tube.   This was probably happening 
all along but, after facing the headtube and removing material, it just got 
worse.   So one of those regular spacers needed to be thicker.  With some 
locknut designs (this one included), there is a pretty small margin of 
error in terms of necessary spacer height:  too many spacers and not enough 
threads will be engaged;  too few spacers, and the locknut will bottom out 
before tightening against the upper cap. Easiest way to figure out how 
many spacers you need is to tighten the locknut *without* spacers, measure 
the gap, and then add spacers that total a couple of mm MORE than that.

Still  If that headset was repeatedly coming loose on you for years, 
then it was likely damaged, and you really should replace it before trying 
anything else.   If it was ovalized or distorted, that could make your 
steering want to "index" to a certain point, which would make it very hard 
to ride no-hands.

Similarly:  This is counter-intuitive but I've heard it mentioned enough 
times that I think there must be something to it:  If a headset is 
tightened slightly TOO MUCH, it will actually make it harder to ride 
no-hands.  You should try loosening it just a bit and experimenting.





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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-26 Thread iamkeith 
Before i forget, another way to solve the "running out of threads" issue is to 
cut more threads.  Since you only need a few, it's not a big deal to do this 
with the thread chasing tool, if the mechanic is willing.  The lock nut and 
most of the threaded top cap will still engage the stronger, factory- formed 
threads.  This would allow you to keep the same headset.

On the other hand, if you spent years with that inexpensive headset repeatedly 
working loose on you as you mention, its likely worn and it's time for a new 
one anywar

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-26 Thread iamkeith 
Looks like there may be a spacer between the top cup and headtube?  (Looks like 
a small gap/shadow line to me) If so, that's pretty unusual and the likely 
culprit.  Easy to get things crooked as you add more pieces and interfaces.  
Show us a pic of the bottom, too.  After my last post, i started wondering if 
maybe they tried to shim the crown race upward?  

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-26 Thread 'Tony McG' via RBW Owners Bunch 
-

>
> 
>
>
> 
> I am a bicycle rider, not mechanic, so I may have misunderstood when I was 
> told about the spacer being installed. My mechanical skills are limited to 
> basic maintenance and adjustments and I usually let the pros do the 
> complicated stuff. I am going to try and attach a photo of the headset and 
> maybe one of you can tell me which spacer was installed. The mechanic that 
> installed it had the day off when I picked up the bike so he wasn't able to 
> point it out to me. If I get all of my chores done today, I may get a 
> chance to ride the Atlantis tomorrow and play with tire pressures and 
> saddle adjustments. I have a Velo-Orange seatpost that is setback further 
> than the Nitto that I may swap out and see if it helps.
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-25 Thread Ryan Fleming 
yes it does and it has quite small diameter tubingIshiwata .022 and 
takes a 27mm diameter seatpost...still have mine and still enjoy it and 
alas I am quite a bit heavier than I was when I bought it in September of 
1993... but I'd prefer not to quantify how much heavier :)

On Thursday, August 25, 2016 at 11:53:11 AM UTC-5, masmojo wrote:
>
> Not Atlantis related, but maybe relevant none the less. I had an XO-1 
> until several months ago. When it was new I rode it around no hands all the 
> time fast forward to a few years ago, I had not ridden it for some time & I 
> am enjoying it. Turned to go down a small  hill, sat back on the seat with 
> my hands off the bars as I'd done thousands of times before and the front 
> end started wobbling violently! I was able to quickly grab the handlebars, 
> but it rattled me a little. 
> The questions go through your head, what was that? Everything with the 
> bike was fine, the only thing that had changed in the equation was ME! When 
> I bought the bike & rode it a lot I weighed 175lbs. When I rode it again!? 
> 240!!
> So adding weight up front might solve the problem, but I think maybe your 
> weight may be effecting the handling? The  XO-1 has very slender seat 
> stays, they probably were not designed for someone my weight, I surmise the 
> frame was flexing more under the increased load! :-(

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-25 Thread masmojo 
Not Atlantis related, but maybe relevant none the less. I had an XO-1 until 
several months ago. When it was new I rode it around no hands all the time fast 
forward to a few years ago, I had not ridden it for some time & I am enjoying 
it. Turned to go down a small  hill, sat back on the seat with my hands off the 
bars as I'd done thousands of times before and the front end started wobbling 
violently! I was able to quickly grab the handlebars, but it rattled me a 
little. 
The questions go through your head, what was that? Everything with the bike was 
fine, the only thing that had changed in the equation was ME! When I bought the 
bike & rode it a lot I weighed 175lbs. When I rode it again!? 240!!
So adding weight up front might solve the problem, but I think maybe your 
weight may be effecting the handling? The  XO-1 has very slender seat stays, 
they probably were not designed for someone my weight, I surmise the frame was 
flexing more under the increased load! :-(

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-25 Thread 'Clayton' via RBW Owners Bunch 



I have a Toyo Atlantis and had shimmy with a rear biased load. Once I put a 
little more weight on the front, it went away. I used Tubus low riders with 
a small Nitto mini rack on the front and had horrible shimmy when loaded. 
When I went to a Nitto big front rack, it went away.  Currently I am 
running the Nitto M-12 mini rack, with my Stuinniker bag, and with King 
Kage " Anything" cages on my fork, which works great for my bikepacking 
needs (but lousy for groceries)There is enough load on the front to 
prevent shimmy, and light enough steering to feel like a bicycle and not a 
semi truck. 

Clayton (Bend)

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-25 Thread iamkeith 
I'm with Alex - that, based on your description, the problem is still 
likely in the headset.  Except I'd go a step further.   When you said "they 
added a spacer because the headset had bottomed out on the threads," did 
you mean they added a spacer between the locknut and the threaded top race 
cap?   Because, if so, that won't solve anything!   If you're running out 
of threads, then the threaded top cap is the part that isn't getting 
tightened down far enough - not the lock nut.   I  would expect the 
mechanic to know this but I suppose that if they're strictly from the 
threadless headset generation, it could be an oversight on their part.

Likely what happened is that, when they faced the headtube earlier, they 
removed just enough material to change the length to where it mattered. 
 Being a Rivendell, the steerer tube was probably sized to put as many 
threads as possible ABOVE the headtube/headset, to allow for extra spacers 
and increased handlebar height.   (the threads that fall internal to the 
headtube are basically "wasted".)  

What you may need is a new headset with a taller stack height at the bottom 
race/cup portion.   Worst case scenario, you may need an extended crown 
race - though it sounds like you're "barely" out of threads, so you'll 
likely be able to find something that works.  Might be an excuse to get a 
King, which are pretty tall.  Or, you could kill two birds with one stone, 
and look for a tall needle bearing option, instead.

just a theory, but looking forward to hearing what you figure out in the end

On Wednesday, August 24, 2016 at 10:19:49 AM UTC-6, Alex Wirth- Owner, 
Yellow Haus Bicycles wrote:
>
> If it were me, I would dissassemble the headset and inspect not only the 
> cups/headtube but also the fork crown/crown race.  Dollars to donuts, based 
> on your description, one or both of those surfaces isn't mating correctly.
>
> On Tuesday, August 23, 2016 at 12:02:58 PM UTC-4, Tony McG wrote:
>>
>> From the beginning: The original owner purchased it as a frameset in '99 
>> because at the time, the future of the Atlantis was questionable. He built 
>> the bike and never rode it because he found a Waterford that he liked 
>> better. I bought it barely used a few years ago and have put a few thousand 
>> miles (mostly gravel) on it. The headset would never stay tight no matter 
>> how hard I dared wrench on the locknut. I took it to a LBS and they removed 
>> the headset and machined the frame so that the headset would fit better. I 
>> rode it for a year, and I still had problems with it loosening. I then took 
>> it to another LBS and they installed a spacer (seems like the headset might 
>> have bottomed out on the threads???). I now have a tight headset, but 
>> I also have a shimmy when I let go of the handlebars. I used to be able 
>> to ride this bike without hands at any speed, but now it wobbles, even at 
>> 10 mph. I don't have any load on the bike except a small seatbag for 
>> tubes/tools, and the tires are the same Soma Cazadero from last year.
>>
>> Any suggestions on what might be causing the shimmy or how to fix it? 
>> Shall I replace it with a NeedleBlasteur from the Riv site and see what 
>> happens?
>>
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-24 Thread Alex Wirth- Owner, Yellow Haus Bicycles 
If it were me, I would dissassemble the headset and inspect not only the 
cups/headtube but also the fork crown/crown race.  Dollars to donuts, based 
on your description, one or both of those surfaces isn't mating correctly.

On Tuesday, August 23, 2016 at 12:02:58 PM UTC-4, Tony McG wrote:
>
> From the beginning: The original owner purchased it as a frameset in '99 
> because at the time, the future of the Atlantis was questionable. He built 
> the bike and never rode it because he found a Waterford that he liked 
> better. I bought it barely used a few years ago and have put a few thousand 
> miles (mostly gravel) on it. The headset would never stay tight no matter 
> how hard I dared wrench on the locknut. I took it to a LBS and they removed 
> the headset and machined the frame so that the headset would fit better. I 
> rode it for a year, and I still had problems with it loosening. I then took 
> it to another LBS and they installed a spacer (seems like the headset might 
> have bottomed out on the threads???). I now have a tight headset, but 
> I also have a shimmy when I let go of the handlebars. I used to be able 
> to ride this bike without hands at any speed, but now it wobbles, even at 
> 10 mph. I don't have any load on the bike except a small seatbag for 
> tubes/tools, and the tires are the same Soma Cazadero from last year.
>
> Any suggestions on what might be causing the shimmy or how to fix it? 
> Shall I replace it with a NeedleBlasteur from the Riv site and see what 
> happens?
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-24 Thread 'Tony McG' via RBW Owners Bunch 
John's post just reminded me that I swapped the Sele Anatomica for a Brooks 
Cambium. There is a big difference in rail lengths on these saddles and 
that would certainly change how the frame is loaded.

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Re: [RBW] Re: Toyo Atlantis Shimmy ???

2016-08-24 Thread 'Stephen Kemp' via RBW Owners Bunch 
Steve said "Bike crash - over in an instant, much too fast to feel any 
emotion."

I crashed last week. There was a slight rustling from the back of the bike, 
like a leaf or something brushing the wheel. I looked down to check it out, 
then when I looked up again I was heading for the kerb! I had enough time 
to think "idiot, you know this road has a curve in it, you ride it every 
day, never do that again!" I remember thinking the ground looked a long way 
down. Then bang, crack, expletive! I got up and checked myself over - no 
damage to me or the bike. And the rustling noise? Never found out - it was 
gone when I remounted...

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread dougP 
Load placement seems to be a major factor in whether a bike shimmies or 
not, and your experience with moving your position slightly is 
interesting.  I noticed I could induce shimmy at a specific speed coasting 
downhill while sitting bolt upright, and it would go away as soon as I 
leaned slightly forward.  When you think about it, the human head weighs 
roughly as much as a bicycle, and it's on a long lever arm.  Granted, our 
body is an automatic damping mechanism, but WE just may be the cause of our 
own shimmies.  

dougP

On Tuesday, August 23, 2016 at 9:10:14 PM UTC-7, John Bokman wrote:
>
> I had frustrations with shimmy at low to moderate speed (10-15 MPH) while 
> sitting upright cruising along a flat road on my Sam. Couldn't figure it 
> out. Had the LBS check it out: wheels, frame alignment, etc. They found 
> nothing. Tightened the headset to offer more friction and that didn't help. 
> What did help was sliding my saddle just a fraction forward toward the 
> bottom bracket. Just a smidge. I had the saddle all the way back on the 
> rails (a Berthoud saddle, don't know how long the rails are offhand). Just 
>  a nudge forward did the trick.
>
>
>
> On Tuesday, August 23, 2016 at 3:34:23 PM UTC-7, Tony McG wrote:
>>
>> This bike has descended hills on SE Minnesota and NE Iowa gravel roads at 
>> over 40 mph with no problems, but I haven't had a chance to try those hills 
>> since the spacer was put in last Winter. It is the low speed without hands 
>> wobble that Bill describes that is bothering me. Since the needle bearing 
>> headset appears to be more of a band aide than a cure, I am going to hold 
>> off throwing parts at the bike until I try changing tire pressures or even 
>> swap out the Cazaderos for  a set of Schwalbe Dureme that I have laying 
>> around. Thanks again everyone!
>>
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread John Bokman 
I had frustrations with shimmy at low to moderate speed (10-15 MPH) while 
sitting upright cruising along a flat road on my Sam. Couldn't figure it 
out. Had the LBS check it out: wheels, frame alignment, etc. They found 
nothing. Tightened the headset to offer more friction and that didn't help. 
What did help was sliding my saddle just a fraction forward toward the 
bottom bracket. Just a smidge. I had the saddle all the way back on the 
rails (a Berthoud saddle, don't know how long the rails are offhand). Just 
 a nudge forward did the trick.



On Tuesday, August 23, 2016 at 3:34:23 PM UTC-7, Tony McG wrote:
>
> This bike has descended hills on SE Minnesota and NE Iowa gravel roads at 
> over 40 mph with no problems, but I haven't had a chance to try those hills 
> since the spacer was put in last Winter. It is the low speed without hands 
> wobble that Bill describes that is bothering me. Since the needle bearing 
> headset appears to be more of a band aide than a cure, I am going to hold 
> off throwing parts at the bike until I try changing tire pressures or even 
> swap out the Cazaderos for  a set of Schwalbe Dureme that I have laying 
> around. Thanks again everyone!
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread 'Tony McG' via RBW Owners Bunch 
This bike has descended hills on SE Minnesota and NE Iowa gravel roads at 
over 40 mph with no problems, but I haven't had a chance to try those hills 
since the spacer was put in last Winter. It is the low speed without hands 
wobble that Bill describes that is bothering me. Since the needle bearing 
headset appears to be more of a band aide than a cure, I am going to hold 
off throwing parts at the bike until I try changing tire pressures or even 
swap out the Cazaderos for  a set of Schwalbe Dureme that I have laying 
around. Thanks again everyone!

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Re: [RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Steve Palincsar 
Be happy.  The "hands on the bars at 20+" version is about the most 
terrifying thing you can experience.  Car crash - not even close, 
because you're too busy to feel any emotion.  Bike crash - over in an 
instant, much too fast to feel any emotion.  Being shot at - not even 
close, it's mostly a "WFT???" of puzzlement (at least, it was for me, in 
RVN).  But with speed wobble you feel it - your emotions wash over you - 
you can see your life flashing before your eyes.



On 08/23/2016 03:48 PM, Bill Lindsay wrote:

Steve pointed out:  "some
will call "shimmy" (and that in some cases, others will call "speed
wobble"

That is an important distinction.  I've never experienced the "hands 
on the bars" version and I've never experienced the "ultra-high speed 
wobble" variant where you have to be going 40mph to have it happen. 
 I've only experienced the no hands riding variant.


On Tuesday, August 23, 2016 at 12:33:41 PM UTC-7, Steve Palincsar wrote:

There are many different things that can cause a vibration that some
will call "shimmy" (and that in some cases, others will call "speed
wobble").  Some of them are various kinds of rider behavior, that
can't
properly be blamed on the bike at all.  Cases in point: shivering.
Holding on to the bars too tight.  I even recall one case (on a
mailing
list) of a guy who would smack the top tube to initiate a
vibration and
then complain if the bike shimmied.


On 08/23/2016 02:51 PM, Bill Lindsay wrote:
> Unfortunately, nobody knows what causes shimmy.  What I mean by
that,
> is that there is not a human being on earth that look at your
bike and
> say "your bike shimmies and here's why".  If we took 9 bikes that
> don't shimmy and 1 that does and put them in a lineup, there is no
> human that can look them over and pick out the shimmying bike.
 If we
> took a non-shimmying bike to the workshop there is no mechanic that
> can do work on it to cause it to shimmy.
>
> What we do know is that shimmy is a resonant oscillation, and
> everybody who knows anything about resonsance knows that if it is
> resonating, then everything that is important is just right in that
> oscillating mechanical system.  To stop it, you change something
that
> is important.  How do you know what's important?  Take a guess and
> start changing things.  If it helped, it was important.  If it
> doesn't, either it wasn't important or you didn't change it enough.
>
> A needlebearing headset has proven to be effective because it adds
> damping to the oscillating mechanical system.  It's still
resonating,
> but the amplitude gets scrubbed off and the self-amplifying part of
> the resonance fades away.  (for electronics geeks, damping
reduces the
> Q of the system).  The damping from a needlebearing headset is from
> friction.  A needlebearing headset does not turn as freely.
>
> Weight distribution on the bike can be quite important, and is the
> only thing you can easily make major changes to.  Some people guess
> that tire width and tire pressure can effect shimmy.  Some
speculate
> that frame stiffness and steering geometry influence whether or
not a
> bike will shimmy, but you are stuck with those things.

Well said, Bill.

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Re: [RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Bill Lindsay 
Steve pointed out:  "some 
will call "shimmy" (and that in some cases, others will call "speed 
wobble"

That is an important distinction.  I've never experienced the "hands on the 
bars" version and I've never experienced the "ultra-high speed wobble" 
variant where you have to be going 40mph to have it happen.  I've only 
experienced the no hands riding variant. 

On Tuesday, August 23, 2016 at 12:33:41 PM UTC-7, Steve Palincsar wrote:
>
> There are many different things that can cause a vibration that some 
> will call "shimmy" (and that in some cases, others will call "speed 
> wobble").  Some of them are various kinds of rider behavior, that can't 
> properly be blamed on the bike at all.  Cases in point: shivering.   
> Holding on to the bars too tight.  I even recall one case (on a mailing 
> list) of a guy who would smack the top tube to initiate a vibration and 
> then complain if the bike shimmied. 
>
>
> On 08/23/2016 02:51 PM, Bill Lindsay wrote: 
> > Unfortunately, nobody knows what causes shimmy.  What I mean by that, 
> > is that there is not a human being on earth that look at your bike and 
> > say "your bike shimmies and here's why".  If we took 9 bikes that 
> > don't shimmy and 1 that does and put them in a lineup, there is no 
> > human that can look them over and pick out the shimmying bike.  If we 
> > took a non-shimmying bike to the workshop there is no mechanic that 
> > can do work on it to cause it to shimmy. 
> > 
> > What we do know is that shimmy is a resonant oscillation, and 
> > everybody who knows anything about resonsance knows that if it is 
> > resonating, then everything that is important is just right in that 
> > oscillating mechanical system.  To stop it, you change something that 
> > is important.  How do you know what's important?  Take a guess and 
> > start changing things.  If it helped, it was important.  If it 
> > doesn't, either it wasn't important or you didn't change it enough. 
> > 
> > A needlebearing headset has proven to be effective because it adds 
> > damping to the oscillating mechanical system.  It's still resonating, 
> > but the amplitude gets scrubbed off and the self-amplifying part of 
> > the resonance fades away.  (for electronics geeks, damping reduces the 
> > Q of the system).  The damping from a needlebearing headset is from 
> > friction.  A needlebearing headset does not turn as freely. 
> > 
> > Weight distribution on the bike can be quite important, and is the 
> > only thing you can easily make major changes to.  Some people guess 
> > that tire width and tire pressure can effect shimmy.  Some speculate 
> > that frame stiffness and steering geometry influence whether or not a 
> > bike will shimmy, but you are stuck with those things. 
>
> Well said, Bill. 
>

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Re: [RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Steve Palincsar 
Certainly cheap enough to try.  Right there on a par with messing around 
with the bags and the load.  When you start changing things like bars 
and stems to vary rider weight distribution it starts to get more 
expensive.  (I mention those because in 1972, my P15 Paramount exhibited 
a truly terrifying speed wobble.  Sometime between then and 1976, a time 
when I messed around a lot with bars and stems, trying to get a better 
fit on a bike that was an inch and a half too small for me, I changed 
/something/ -- never did find out what -- that made the speed wobble 
stop happening. And during that time period, the only other components I 
changed were front and rear derailleurs, and nobody's ever suggested 
they play a role in speed wobble.



On 08/23/2016 03:28 PM, 'Tony McG' via RBW Owners Bunch wrote:
This is a 61 cm Atlantis. The tire pressure looks like a good place to 
start experimenting. I have been running the Cazadero at about 30-35 
psi on the front because of our chunky gravel roads. The seatbag and 
contents probably weigh less than a pound, but I may try to see how a 
handlebar bag affects the shimmy. Thanks for your replies!


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Re: [RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Steve Palincsar 
There are many different things that can cause a vibration that some 
will call "shimmy" (and that in some cases, others will call "speed 
wobble").  Some of them are various kinds of rider behavior, that can't 
properly be blamed on the bike at all.  Cases in point: shivering.  
Holding on to the bars too tight.  I even recall one case (on a mailing 
list) of a guy who would smack the top tube to initiate a vibration and 
then complain if the bike shimmied.



On 08/23/2016 02:51 PM, Bill Lindsay wrote:
Unfortunately, nobody knows what causes shimmy.  What I mean by that, 
is that there is not a human being on earth that look at your bike and 
say "your bike shimmies and here's why".  If we took 9 bikes that 
don't shimmy and 1 that does and put them in a lineup, there is no 
human that can look them over and pick out the shimmying bike.  If we 
took a non-shimmying bike to the workshop there is no mechanic that 
can do work on it to cause it to shimmy.


What we do know is that shimmy is a resonant oscillation, and 
everybody who knows anything about resonsance knows that if it is 
resonating, then everything that is important is just right in that 
oscillating mechanical system.  To stop it, you change something that 
is important.  How do you know what's important?  Take a guess and 
start changing things.  If it helped, it was important.  If it 
doesn't, either it wasn't important or you didn't change it enough.


A needlebearing headset has proven to be effective because it adds 
damping to the oscillating mechanical system.  It's still resonating, 
but the amplitude gets scrubbed off and the self-amplifying part of 
the resonance fades away.  (for electronics geeks, damping reduces the 
Q of the system).  The damping from a needlebearing headset is from 
friction.  A needlebearing headset does not turn as freely.


Weight distribution on the bike can be quite important, and is the 
only thing you can easily make major changes to.  Some people guess 
that tire width and tire pressure can effect shimmy.  Some speculate 
that frame stiffness and steering geometry influence whether or not a 
bike will shimmy, but you are stuck with those things.


Well said, Bill.

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread 'Tony McG' via RBW Owners Bunch 
This is a 61 cm Atlantis. The tire pressure looks like a good place to 
start experimenting. I have been running the Cazadero at about 30-35 psi on 
the front because of our chunky gravel roads. The seatbag and contents 
probably weigh less than a pound, but I may try to see how a handlebar bag 
affects the shimmy. Thanks for your replies!

>
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Bill Lindsay 
Unfortunately, nobody knows what causes shimmy.  What I mean by that, is 
that there is not a human being on earth that look at your bike and say 
"your bike shimmies and here's why".  If we took 9 bikes that don't shimmy 
and 1 that does and put them in a lineup, there is no human that can look 
them over and pick out the shimmying bike.  If we took a non-shimmying bike 
to the workshop there is no mechanic that can do work on it to cause it to 
shimmy.  

What we do know is that shimmy is a resonant oscillation, and everybody who 
knows anything about resonsance knows that if it is resonating, then 
everything that is important is just right in that oscillating mechanical 
system.  To stop it, you change something that is important.  How do you 
know what's important?  Take a guess and start changing things.  If it 
helped, it was important.  If it doesn't, either it wasn't important or you 
didn't change it enough.  

A needlebearing headset has proven to be effective because it adds damping 
to the oscillating mechanical system.  It's still resonating, but the 
amplitude gets scrubbed off and the self-amplifying part of the resonance 
fades away.  (for electronics geeks, damping reduces the Q of the system). 
 The damping from a needlebearing headset is from friction.  A 
needlebearing headset does not turn as freely.  

Weight distribution on the bike can be quite important, and is the only 
thing you can easily make major changes to.  Some people guess that tire 
width and tire pressure can effect shimmy.  Some speculate that frame 
stiffness and steering geometry influence whether or not a bike will 
shimmy, but you are stuck with those things.  

Bill Lindsay
El Cerrito, CA 

On Tuesday, August 23, 2016 at 9:02:58 AM UTC-7, Tony McG wrote:
>
> From the beginning: The original owner purchased it as a frameset in '99 
> because at the time, the future of the Atlantis was questionable. He built 
> the bike and never rode it because he found a Waterford that he liked 
> better. I bought it barely used a few years ago and have put a few thousand 
> miles (mostly gravel) on it. The headset would never stay tight no matter 
> how hard I dared wrench on the locknut. I took it to a LBS and they removed 
> the headset and machined the frame so that the headset would fit better. I 
> rode it for a year, and I still had problems with it loosening. I then took 
> it to another LBS and they installed a spacer (seems like the headset might 
> have bottomed out on the threads???). I now have a tight headset, but 
> I also have a shimmy when I let go of the handlebars. I used to be able 
> to ride this bike without hands at any speed, but now it wobbles, even at 
> 10 mph. I don't have any load on the bike except a small seatbag for 
> tubes/tools, and the tires are the same Soma Cazadero from last year.
>
> Any suggestions on what might be causing the shimmy or how to fix it? 
> Shall I replace it with a NeedleBlasteur from the Riv site and see what 
> happens?
>

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Re: [RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Deacon Patrick 
To second this, my Hunq shimmies with too much up front (making it 
unridable on pavement, let alone single track), but handles more total 
weight amazingly well with all but a wee bit in the rear and the rest in 
the front. Others love their Hunqapillars loaded in the front, with just a 
wee bit in the back, so rider differences seem to play a part as well. Play 
with the load, how secure it is, riding technique (which necessarily 
changes with more weight), load balance front/rear and side to side, how 
far up and/or out the load is (especially on the front. Tighter and lower 
and centered/balanced side to side is more solid).

With abandon,
Patrick

On Tuesday, August 23, 2016 at 12:13:55 PM UTC-6, Steve Palincsar wrote:
>
> So it's not the bike, it's how the load was distributed.
>
> On 08/23/2016 01:30 PM, Sky Coulter wrote:
>
> Tony, 
>
> Don't know how helpful this might be but I was experiencing shimmy on my 
> 60cm saluki, I tried a number of things to fix it, including a 
> needlebearing headset (which helped i think). But the biggest change was 
> when i swapped out the cockpit from a 90mm stem to a 100mm stem. Shifting a 
> bit of my weight (240lbs) forward over the front wheel reduced the hands on 
> shimmy more than anything else.  With a load in the front basket and hands 
> off, there is still a bit of wagging from the handlebars, but more like the 
> wagging of a dog getting petted, than oone being taken outside for a walk.
>
> Sky in New west 
>
> On Tuesday, August 23, 2016 at 9:46:05 AM UTC-7, Trenker wrote: 
>>
>>
>>
>> Last summer I was on a short bike trip thinking to myself, during that 
>> time on the bike when you have lots of time to think, that I have never 
>> been bothered by shimmy on any bike that I could remember. The same morning 
>> I kept hearing a knocking sound while pedaling or gliding at low speed, 
>> which went away when I put both hands lightly on the handlebar. I gradually 
>> figured out it was the fender knocking against the tire, and I realized 
>> that I had always experienced shimmy, but never realized it or been 
>> bothered much by it. This is on a 66 cm Toyo Atlantis with rear panniers 
>> and a front basket. The same morning I was having the prolonged impression 
>> of how much I liked this bike for touring. 
>>
>>
>> During that trip I had enough time to experiment and ponder the shimmy, 
>> and I realized that it only happened at low speed, and that at higher 
>> speeds, eg. descending on asphalt or gravel, the bike was rock solid. Which 
>> is a nice concession. 
>>
>>
>> I think shimmy can be finely tuned in or out of a bike. Going to a 
>> slightly narrower tire can improve things, as can pumping up the front tire 
>> to the same adequate pressure as the back; it isn’t written in stone that 
>> the front tire has to be at a lower pressure. 
>>
>>
>> Even the road surface can affect or initiate shimmy: it looks flat but 
>> there are subtle undulations caused by car tires; they are a lot more 
>> obvious on gravel roads, before or after intersections. 
>>
>>
>> If you are tweaking your setup to reduce shimmy, you can test it at home 
>> by standing beside the bike and rapping the side of the handlebar with the 
>> heel of your hand: you will be able to see if the vibrations focus on the 
>> front end ( shimmy ) or condense around the back end of the bike ( ideal, 
>> which I now have with a small basket on front and saddlebag tied to a small 
>> home-made rear rack.) Tomorrow morning I head out on another short trip and 
>> I’ll have plenty of time to see how I like this setup. 
>>
>>
>> I suspect that tall riders on big bikes probably always experience a 
>> certain amount of shimmy, as well as a certain amount of frame flex, but we 
>> are used to it and don’t know any different. I wonder what size your 
>> Atlantis is? 
>>
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Re: [RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Steve Palincsar 

So it's not the bike, it's how the load was distributed.


On 08/23/2016 01:30 PM, Sky Coulter wrote:

Tony,

Don't know how helpful this might be but I was experiencing shimmy on 
my 60cm saluki, I tried a number of things to fix it, including a 
needlebearing headset (which helped i think). But the biggest change 
was when i swapped out the cockpit from a 90mm stem to a 100mm stem. 
Shifting a bit of my weight (240lbs) forward over the front wheel 
reduced the hands on shimmy more than anything else.  With a load in 
the front basket and hands off, there is still a bit of wagging from 
the handlebars, but more like the wagging of a dog getting petted, 
than oone being taken outside for a walk.


Sky in New west

On Tuesday, August 23, 2016 at 9:46:05 AM UTC-7, Trenker wrote:



Last summer I was on a short bike trip thinking to myself, during
that time on the bike when you have lots of time to think, that I
have never been bothered by shimmy on any bike that I could
remember. The same morning I kept hearing a knocking sound while
pedaling or gliding at low speed, which went away when I put both
hands lightly on the handlebar. I gradually figured out it was the
fender knocking against the tire, and I realized that I had always
experienced shimmy, but never realized it or been bothered much by
it. This is on a 66 cm Toyo Atlantis with rear panniers and a
front basket. The same morning I was having the prolonged
impression of how much I liked this bike for touring.


During that trip I had enough time to experiment and ponder the
shimmy, and I realized that it only happened at low speed, and
that at higher speeds, eg. descending on asphalt or gravel, the
bike was rock solid. Which is a nice concession.


I think shimmy can be finely tuned in or out of a bike. Going to a
slightly narrower tire can improve things, as can pumping up the
front tire to the same adequate pressure as the back; it isn’t
written in stone that the front tire has to be at a lower pressure.


Even the road surface can affect or initiate shimmy: it looks flat
but there are subtle undulations caused by car tires; they are a
lot more obvious on gravel roads, before or after intersections.


If you are tweaking your setup to reduce shimmy, you can test it
at home by standing beside the bike and rapping the side of the
handlebar with the heel of your hand: you will be able to see if
the vibrations focus on the front end ( shimmy ) or condense
around the back end of the bike ( ideal, which I now have with a
small basket on front and saddlebag tied to a small home-made rear
rack.) Tomorrow morning I head out on another short trip and I’ll
have plenty of time to see how I like this setup.


I suspect that tall riders on big bikes probably always experience
a certain amount of shimmy, as well as a certain amount of frame
flex, but we are used to it and don’t know any different. I wonder
what size your Atlantis is?


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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread dougP 
Tony:

I've had a 58 cm Atlantis since '03.  With only a light load as you 
describe it never shimmied.  

My first experience with shimmy was the first time I had it loaded for a 
tour, and all of the weight was on the rear.  Others suggested getting some 
weight forward, so after that I started experimenting with loading.  
Eventually I came to the conclusion that some front bias was preferable.  

While the above doesn't seem applicable to your situation,  I suggest 
moving your rear bag load to the front.  At one point in my experiments, I 
was able to induce shimmy with only a small rear saddlebag with tools, 
tubes, etc.  A specific set of conditions was req'd as well as me sitting 
bolt upright on the bike.  Simply moving that bag (<3 lbs?) to the 
handlebars solved the problem.  Simple experiment to try.

The needle bearing headset may be beneficial but I don't recall anyone 
claiming it to be "the cure" for all shimmies.  Shimmy seems to be an 
elusive problem with lots of possible sources, so tough to ID a single 
source in a specific case.  

dougP  

On Tuesday, August 23, 2016 at 9:02:58 AM UTC-7, Tony McG wrote:
>
> From the beginning: The original owner purchased it as a frameset in '99 
> because at the time, the future of the Atlantis was questionable. He built 
> the bike and never rode it because he found a Waterford that he liked 
> better. I bought it barely used a few years ago and have put a few thousand 
> miles (mostly gravel) on it. The headset would never stay tight no matter 
> how hard I dared wrench on the locknut. I took it to a LBS and they removed 
> the headset and machined the frame so that the headset would fit better. I 
> rode it for a year, and I still had problems with it loosening. I then took 
> it to another LBS and they installed a spacer (seems like the headset might 
> have bottomed out on the threads???). I now have a tight headset, but 
> I also have a shimmy when I let go of the handlebars. I used to be able 
> to ride this bike without hands at any speed, but now it wobbles, even at 
> 10 mph. I don't have any load on the bike except a small seatbag for 
> tubes/tools, and the tires are the same Soma Cazadero from last year.
>
> Any suggestions on what might be causing the shimmy or how to fix it? 
> Shall I replace it with a NeedleBlasteur from the Riv site and see what 
> happens?
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Sky Coulter 
Tony,

Don't know how helpful this might be but I was experiencing shimmy on my 
60cm saluki, I tried a number of things to fix it, including a 
needlebearing headset (which helped i think). But the biggest change was 
when i swapped out the cockpit from a 90mm stem to a 100mm stem. Shifting a 
bit of my weight (240lbs) forward over the front wheel reduced the hands on 
shimmy more than anything else.  With a load in the front basket and hands 
off, there is still a bit of wagging from the handlebars, but more like the 
wagging of a dog getting petted, than oone being taken outside for a walk.

Sky in New west 

On Tuesday, August 23, 2016 at 9:46:05 AM UTC-7, Trenker wrote:
>
>
>
> Last summer I was on a short bike trip thinking to myself, during that 
> time on the bike when you have lots of time to think, that I have never 
> been bothered by shimmy on any bike that I could remember. The same morning 
> I kept hearing a knocking sound while pedaling or gliding at low speed, 
> which went away when I put both hands lightly on the handlebar. I gradually 
> figured out it was the fender knocking against the tire, and I realized 
> that I had always experienced shimmy, but never realized it or been 
> bothered much by it. This is on a 66 cm Toyo Atlantis with rear panniers 
> and a front basket. The same morning I was having the prolonged impression 
> of how much I liked this bike for touring. 
>
>
> During that trip I had enough time to experiment and ponder the shimmy, 
> and I realized that it only happened at low speed, and that at higher 
> speeds, eg. descending on asphalt or gravel, the bike was rock solid. Which 
> is a nice concession. 
>
>
> I think shimmy can be finely tuned in or out of a bike. Going to a 
> slightly narrower tire can improve things, as can pumping up the front tire 
> to the same adequate pressure as the back; it isn’t written in stone that 
> the front tire has to be at a lower pressure. 
>
>
> Even the road surface can affect or initiate shimmy: it looks flat but 
> there are subtle undulations caused by car tires; they are a lot more 
> obvious on gravel roads, before or after intersections. 
>
>
> If you are tweaking your setup to reduce shimmy, you can test it at home 
> by standing beside the bike and rapping the side of the handlebar with the 
> heel of your hand: you will be able to see if the vibrations focus on the 
> front end ( shimmy ) or condense around the back end of the bike ( ideal, 
> which I now have with a small basket on front and saddlebag tied to a small 
> home-made rear rack.) Tomorrow morning I head out on another short trip and 
> I’ll have plenty of time to see how I like this setup. 
>
>
> I suspect that tall riders on big bikes probably always experience a 
> certain amount of shimmy, as well as a certain amount of frame flex, but we 
> are used to it and don’t know any different. I wonder what size your 
> Atlantis is? 
>
>

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[RBW] Re: Toyo Atlantis Shimmy ???

2016-08-23 Thread Trenker 


Last summer I was on a short bike trip thinking to myself, during that time 
on the bike when you have lots of time to think, that I have never been 
bothered by shimmy on any bike that I could remember. The same morning I 
kept hearing a knocking sound while pedaling or gliding at low speed, which 
went away when I put both hands lightly on the handlebar. I gradually 
figured out it was the fender knocking against the tire, and I realized 
that I had always experienced shimmy, but never realized it or been 
bothered much by it. This is on a 66 cm Toyo Atlantis with rear panniers 
and a front basket. The same morning I was having the prolonged impression 
of how much I liked this bike for touring. 


During that trip I had enough time to experiment and ponder the shimmy, and 
I realized that it only happened at low speed, and that at higher speeds, 
eg. descending on asphalt or gravel, the bike was rock solid. Which is a 
nice concession. 


I think shimmy can be finely tuned in or out of a bike. Going to a slightly 
narrower tire can improve things, as can pumping up the front tire to the 
same adequate pressure as the back; it isn’t written in stone that the 
front tire has to be at a lower pressure. 


Even the road surface can affect or initiate shimmy: it looks flat but 
there are subtle undulations caused by car tires; they are a lot more 
obvious on gravel roads, before or after intersections. 


If you are tweaking your setup to reduce shimmy, you can test it at home by 
standing beside the bike and rapping the side of the handlebar with the 
heel of your hand: you will be able to see if the vibrations focus on the 
front end ( shimmy ) or condense around the back end of the bike ( ideal, 
which I now have with a small basket on front and saddlebag tied to a small 
home-made rear rack.) Tomorrow morning I head out on another short trip and 
I’ll have plenty of time to see how I like this setup. 


I suspect that tall riders on big bikes probably always experience a 
certain amount of shimmy, as well as a certain amount of frame flex, but we 
are used to it and don’t know any different. I wonder what size your 
Atlantis is? 

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