Doug
I am arriving at that conclusion and towards that end I'm also
prepared to rule out one compelling variable. My experiments suggest
that the compliance (flexibility) of the rear rack itself is NOT a
significant contributor to shimmy on my Hillborne.
The experiment was that I swapped rear ra
I've run similar loading experiments on my Atlantis. The unloaded set-
up is a Nitto small front rack with Acorn Box Rando bag which I often
load up to 6-8 lbs without issue. I have a Nitto Big Rear Rack (2 lbs
of real steel) for anything I may pick up along the way. Unless I've
got a box of boo
The drinard video is very good. That's exactly the thing I'm looking
at when running my experiments.
On Dec 21, 9:34 pm, Tim McNamara wrote:
> Try the simple things first: move the saddle slightly forward or
> back, maybe 1/2", to change the weight distribution of you on the
> bike. Chan
Tim wrote:
> This is Rob English crashing at the Battle Mountain IHPVA event on
> level terrain at about 70 mph (I bet he appreciated his fairing very
> much). It appears to me that his pedaling effort caused the problem
> and that as the bike started to wobble, his pedaling amplified it.
T
Try the simple things first: move the saddle slightly forward or
back, maybe 1/2", to change the weight distribution of you on the
bike. Change the distribution of stuff you carry on the bike (or
consider carrying less stuff). Raise or lower the bars to change
your position. Make sure t
I was thinking that the factor is the weight of the rear bag, not the
rack. Can you verify if without the rack but with the bag anything
changes?
My Atlantis with the same rack-bag combo + Noodle bars and shimmies.
When I put the Albatross bars it didn't shimmy but I couldn't get used
to them. Now
whups, scratch that - i've used the R-FIFTEEN, not the R-14.
-a
On Dec 21, 8:14 pm, andrew hill wrote:
> I've got a 56 Sam that I ran a R-14 on with 2 Ortliebs fairly well loaded, or
> (alternatively) a Big Loafer on top... nary a shimmy (with a mini+loaf on the
> front).
>
> ymmv, of course,
I've got a 56 Sam that I ran a R-14 on with 2 Ortliebs fairly well loaded, or
(alternatively) a Big Loafer on top... nary a shimmy (with a mini+loaf on the
front).
ymmv, of course, but i never noticed any "flexiness" from the R-14.
-a
On Dec 21, 2010, at 8:08 PM, doug peterson wrote:
> Just l
Just looked up the R-14 on Riv's site: 13 lbs capacity. It's
surprising how quickly weight can add up. The R-14 is an elegant
looking rack but with just the support struts for stability it may
lack lateral stiffness.
dougP
On Dec 21, 2:20 pm, james black wrote:
> On Tue, Dec 21, 2010 at 13:25
I understand it well enough on my Hillborne that I can avoid shimmy
when I want to, so I don't think I have a problem to solve. We've
never read a convincing description for why bikes shimmy, that's
true. But I'd argue we've never read a convincing description for why
any INDIVIDUAL bike shimmies
I was thinking another variable may be wheels. Have you tried swapping
wheels from another bike to see if that changes or helps anything? Or
tire switching as well?
both seem like easy changes to make. Rotating components can certainly
affect the dynamic response of the bike.
Other things like fr
On Tue, 2010-12-21 at 14:29 -0800, William wrote:
> Nobody conclusively says that such things are
> causes or enablers of shimmy, or will bet their life on removing such
> loads being a cure to shimmy
They'd be very foolish to do so, since there are many things that can
cause shimmy including ride
I'm tracking that...In my notes I estimated the Sackville Saddlesack
Large and it's contents weighed 12 pounds. There are numerous
speculations in the literature about high mounted floppy loads being
associated with shimmy. Nobody conclusively says that such things are
causes or enablers of shimm
On Tue, Dec 21, 2010 at 13:25, William wrote:
> I loaded my 56cm Bombadil with the trunksack small on the Nitto Mini
> front. I moved the Nitto R-14 rear and the loaded Saddlesack Large
> over to the Bombadil. The Bombadil does shimmy with that load. But
> it is at a much higher frequency and a
William:
Did you note the weights at each end? Riv says the R-14 isn't meant
for much weight (don't recall the number but it's conservative) so
perhaps some rack movement?
dougP
On Dec 21, 1:25 pm, William wrote:
> Update on the research front. In the next round of testing I put the
> identic
Update on the research front. In the next round of testing I put the
identical load on a different bike.
I loaded my 56cm Bombadil with the trunksack small on the Nitto Mini
front. I moved the Nitto R-14 rear and the loaded Saddlesack Large
over to the Bombadil. The Bombadil does shimmy with th
Yeah, I've read that article. What "light" were you referring to?
In that article he definitely makes himself look smart by describing
'nutation' which is a term that 99.9% of his readers don't know. He
describes that as a driving force for why bikes shimmy, but has only
guesses for why bikes do
Builder Dave Moulton sheds some light on the subject in this 2006 blog
entry:
http://davesbikeblog.squarespace.com/blog/2006/8/18/shimmy-re-visited.html
On Dec 13, 7:59 pm, William wrote:
> I weigh about 175. The whole bike rig with both bags on it as
> described above is probably in the low 4
I weigh about 175. The whole bike rig with both bags on it as
described above is probably in the low 40s. So maybe 215 bike + cargo
+ rider. Straight medium. :)
My bars are 1-2 inches above saddle height.
On Dec 13, 4:21 pm, Seth Vidal wrote:
> On Mon, Dec 13, 2010 at 7:13 PM, William wrote
It's a Nitto R-14. The saddlesack large does flop around when you
rock the bike, so the compliance that I think you are correctly
seeking might be there as well.
On Dec 13, 4:19 pm, james black wrote:
> On Mon, Dec 13, 2010 at 16:13, William wrote:
> > The fundamental conclusion I can make alre
On Mon, Dec 13, 2010 at 7:13 PM, William wrote:
> The fundamental conclusion I can make already is that front end shimmy
> at moderate speed no-handed is not a fundamental property of this
> bicycle. It's a property of a particular configuration on this
> bicycle. If I don't like it, I can confi
On Mon, Dec 13, 2010 at 16:13, William wrote:
> The fundamental conclusion I can make already is that front end shimmy
> at moderate speed no-handed is not a fundamental property of this
> bicycle.
What kind of rear rack do you have? Based on your account, I'm
guessing that an overly flexible rea
I've run my first several experiments. My bike was in a state where
it was really easy to make it shimmy in a way that was/is not life
threatening. The bike is a 56cm Hillborne. It's got fenders, front
and rear racks a Saddlesack Large on the back and a Trunksack small in
front. Riding no hands
Hey, I resemble that remark. 220 also. More a combination of not
having more major hills to descend and being a natural born chicken.
But, hey, we need the eggs.
Actually those photos aren't scary to me. In fact, would be nice to
have only that much snow on the ground. Could have been out ridin
I did in fact, mean 26" frame w/ 27" wheels.
Sent from my Verizon Wireless BlackBerry
-Original Message-
From: "Bill M."
Sender: rbw-owners-bunch@googlegroups.com
Date: Sun, 12 Dec 2010 22:22:52
To: RBW Owners Bunch
Reply-To: rbw-owners-bunch@googlegroups.com
Subje
You sure he didn't mean a 26" frame size (not wheel size)?
On Dec 12, 11:42 am, Steve Palincsar wrote:
> On Sun, 2010-12-12 at 14:40 -0500, Robert Zeidler wrote:
> > I concur with your opinion on the Paramount. I, too, have a few of the 26"
> > bikes, all 531 , and find they are rock steady. I
Well being 220 lbs means gravity is my friend on the downhill. That
57 was scary with the wobble but have hit 65 mph on long straight shot
that was solid smooth and not scary at all. The desire to go that
fast has finally faded. I guess the adrenalin junky in me has settled
down.. another good r
As long as they don't have harps, you're safe. (Bad joke, totally
admit it.)
Good for you for getting the bike up to 57. Have been up to 40 on the
Sam Hillborne. Fast enough for me.
No shimmy on that descent. Unless my knocking knees caused something.
Eric Platt
St. Paul, MN
On Dec 12, 1:07
I'm in agreement with you concerning wheel sizes of the 1970's
(Chicago era) Paramounts. The touring models (P10-9, P15-9, and the
P60, P65 Ladies' models) were factory standard equipped with a 27"
wheel size (either the 27" x 1 1/4" Schwinn Le Tour tire or later the
27" x 1 1/8" Schwinn Super Rec
On Sun, 2010-12-12 at 14:40 -0500, Robert Zeidler wrote:
> I concur with your opinion on the Paramount. I, too, have a few of the 26"
> bikes, all 531 , and find they are rock steady. Is this a 27" wheel thing
> maybe?
>
I do not recall a 1972 Paramount coming with 26" wheels. FWIW, mine had
I concur with your opinion on the Paramount. I, too, have a few of the 26"
bikes, all 531 , and find they are rock steady. Is this a 27" wheel thing
maybe?
Sent from my iPad
On Dec 12, 2010, at 12:43 PM, Jim Cloud wrote:
> Your experience with a 1972 Paramount is interesting. I have a 1977
> It would interesting to know what combination of factors are
> attributable to a bike having a tendency for speed wobbles.
>
> Jim Cloud
> Tucson, AZ
>
Which is the subject of the Shimmy Review in the Winter BQ!
The Winter BQ recounts opinions and experiences from the past 100 years in a
few pag
Or those of the background singers?
On Sun, Dec 12, 2010 at 12:28 PM, Kelly wrote:
> So you're saying the harmonics of the guitar may stop the woble? Good
> thought there. :)
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "RBW Owners Bunch" group.
> To po
Your experience with a 1972 Paramount is interesting. I have a 1977
P-15 Paramount, that I'm still riding, and I've never experienced any
problems with speed wobbles. It's a 26" frame bike with a 110mm
extension on the stem. It's rock steady descending on steep roads
with speeds attained of 45-5
So you're saying the harmonics of the guitar may stop the woble? Good
thought there. :)
--
You received this message because you are subscribed to the Google Groups "RBW
Owners Bunch" group.
To post to this group, send email to rbw-owners-bu...@googlegroups.com.
To unsubscribe from this group, s
... at 57 mph in a turn I was afraid of that bike at speed ...
Only thing crazier I've ever heard of was Arlo Gutherie riding his
motorcycle down the mountain road... playin' his guitar... Geez,
Kelly, STFD... gonna kill yourself.
On Dec 11, 11:38 am, Kelly wrote:
> I had an experiance with a hi
Shimmy,shimmy,cocoa pop
On Dec 10, 1:03 pm, William wrote:
> I am a recent subscriber of Bicycle Quarterly. I had thought about
> subscribing for a while, and two things about the newest issue made me
> pull the trigger. One was the write up about the Bilenky 650B tandem
> (dude, I want on
I had an experiance with a high speed shimmy .. always over 50 mph and
if I was trying to turn it was even worse. Tried everything. Giant
eventually gave me a new frame .. only because they didn't have a
matching fork for the frame I had.. in that case they believed it to be
in the frame. It was pu
I also have a first-generation Kogswell P/R. It shimmied badly with a
5 - 10 pound load in a Wald basket zip-tied to the top of a Blackburn
rear rack. I could feel the weight of the load wagging like a dog's
tail. With the same commuting payload in panniers on the same rack,
no shimmy. There wa
Two (hopefully quick) examples from my limited experience in the past
few years. Worst shimmy ever had was on a 1st generation Kogswell
that Esteban now owns. Would even shimmy when riding with both hands
on the bars. A guess - my weight at the time acted to overload the
bike causing the shimmy.
Jan
Again, I appreciate your thoughts, and your massive contributions.
I'll post findings once I have findings to post.
Have a great weekend
On Dec 10, 5:42 pm, Jan Heine wrote:
> On Dec 10, 11:07 am, William wrote:
>
> > With all due respect, this
> > needle bearing headset thing, especially
On Dec 10, 11:07 am, William wrote:
> With all due respect, this
> needle bearing headset thing, especially, strikes me as voodoo.
It may be voodoo, but so far, it's worked in 100% of the cases we've
tried. Mark's Ti Cycles shimmied terribly once he added a handlebar
bag, as soon as he took his h
On Dec 10, 11:07 am, William wrote:
> I'm extremely flattered at your almost instant reply.
I try to keep up with a few lists, just like everybody else. Until I
get too busy...
> Regarding shimmy, it's possible that my expectations were
> unrealistic. I thought I'd learn some conclusive, empiri
Whooee, take off for bike ride & look what I missed! I'll read the
entire thread but for the moment here's some Riv content to chew on:
The Atlantis is arguably one of the most stable bikes made. With my
normal collection of rackage and a moderate sized front bag that'll
hold a few pounds, it's
10:1 he lurks here...
On Dec 10, 10:38 am, Bruce wrote:
> Send this part off to Eben Weiss. He can always use good material..
>
>
> From: William
>
> >>The Cliff-notes synopsis is: "I don't know what causes shimmy, nor does
>
> anyone else. Here's what several o
According to Jan and others, the headset is a source of damping
friction. Things that resonate out of control are underdamped. So if
the headset has too little friction, then putting more friction on it
will reduce the amplitude response of the system, all other things
being equal. Higher viscos
wish I had my BQ already.
On Fri, Dec 10, 2010 at 2:11 PM, wrote:
> At last, a voice of reason!
>
> In a message dated 12/10/2010 4:21:39 P.M. Eastern Standard Time,
> montclairbob...@gmail.com writes:
>
> With some exceptions (like life-threatening high-speed wobs, no
> thanks)... maybe it's
At last, a voice of reason!
In a message dated 12/10/2010 4:21:39 P.M. Eastern Standard Time,
montclairbob...@gmail.com writes:
With some exceptions (like life-threatening high-speed wobs, no
thanks)... maybe it's time we just embrace the shimmy... it could just
be our bikes telling us:
I would suggest adjusting / slash tightening the headset, before I
bought a new one.
My Ebisu All Purpose frame had a very slight front end shimmy as soon
as I put it together. After two years of riding, I became aware that
the shimmy was very gradually getting worse. One day I checked the
heads
With some exceptions (like life-threatening high-speed wobs, no
thanks)... maybe it's time we just embrace the shimmy... it could just
be our bikes telling us:
Slow the F down...
Put your damn hands back on the bars
Get a trailer if you wanna haul sh**
Turn off that awful music on your iPod, it's
Mike
This is part of the voodoo feel to the whole thing. You can find an
article that says knobbies damp out shimmy. You can find another that
says knobbies supply the excitation force for shimmy. You can find
another article that states that wide tires like knobbies are
typically more complian
> Allan, thanks for that suggestion.
Sure. And to clarify, since your a new sub and may not realize, it's
the _Reader's_ list. Jan is also on the list and probably monitors it,
much as he does here and elsewhere, but it is of the Reader's. There
is no party line and polite criticism, is certainly
Funny, Bill, that you say your Hillborne shimmied. The one I had (now
sold) was the most stable bike I've ever ridden with no hands in my
life. I could have had a 3 course dinner while riding and not even
think about touching the bars. I had the standard Riv supplied Tange
headset and even with Sc
The shimmy article was OK. In general, I'm not a fan of every BQ
article I read, but BQ is the only publication I read cover to cover
every time.
FWIW the two fender articles alone make buying a copy worthwhile.
On Dec 10, 2:07 pm, William wrote:
> Jan
>
> I'm extremely flattered at your almost
Allan, thanks for that suggestion.
On Dec 10, 11:10 am, Allan in Portland wrote:
> BTW, there's the Bicycle Quarterly Reader's Review
> list,http://groups.google.com/group/bqrr, that was created as a venue for
> precisely these types of discussions.
>
> Not saying you can't discuss the mag anyw
BTW, there's the Bicycle Quarterly Reader's Review list,
http://groups.google.com/group/bqrr , that was created as a venue for
precisely these types of discussions.
Not saying you can't discuss the mag anywhere you please, just saying
we'd really appreciate the discussion there. :-)
Carry on,
-Al
On Fri, 2010-12-10 at 11:04 -0800, newenglandbike wrote:
> OK, hoping not to spoil for folks who haven't seen the article yet- I
> thought it was a decent survey of plausible causes for shimmy.It
> didn't reveal a catch-all cure for the problem, but that's probably b/
> c none could possibly e
Jan
I'm extremely flattered at your almost instant reply. I don't know if
that means you regularly read the list or if somebody you know does.
I admire your work deeply and endorse your publication
enthusiastically. Every copy of BQ I've seen has had something
astonishing for me. This issue was
OK, hoping not to spoil for folks who haven't seen the article yet- I
thought it was a decent survey of plausible causes for shimmy.It
didn't reveal a catch-all cure for the problem, but that's probably b/
c none could possibly exist, since there are so many possible causes,
some of them combi
On Fri, 2010-12-10 at 10:29 -0800, Jan Heine wrote:
> I am beginning to believe that all bikes have a tendency to shimmy,
> and depending on a number of factors, the oscillations either are
> dampened or self-reinforce.
Which is exactly what Jobst Brandt says in the rec.bicycles.tech FAQ.
--
Y
William,
I am sorry you are disappointed with our article on shimmy. We tried
to offer summary of the factors that appear to cause or exacerbate
shimmy. After all, we know that some bikes rarely shimmy (heavy tubes,
long trail, no load, skinny tires). It appears that shimmy is a multi-
faceted pro
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