[RBW] Re: shimmy 71.5 head angle

2020-08-31 Thread Brian Campbell
Headset installed correctly? Fork bent? Too much weight in the front? Weight too high on the bike? Lightweight tubing that flexes too much? Saddle height too high which generates a rocking motion and destabilizes the bikes center of gravity? On Monday, August 31, 2020 at 1:54:05 PM UTC-4, Sam P

Re: [RBW] Re: Shimmy cured

2013-01-05 Thread Anne Paulson
My Atlantis handles 50 or 60 pounds, with maybe 25 up front on lowriders, with aplomb. The only time I get shimmy is when putting a lot of weight in my handlebar bag; then I get shimmy on the downhills. It is alleviated at once if I remove a couple of heavy things from the handlebar bag. I use an O

Re: [RBW] Re: Shimmy cured

2013-01-05 Thread Kelly
When it shimmies at all speeds and doesn't dissipate when touching the top tube it is usually from what I've seen .. a:] Headset (either adjustment or worn out) b:] alignment (check forks If it was when loaded then moving loads etc would usually fix it. My experience with front loads is

Re: [RBW] Re: Shimmy cured

2013-01-05 Thread Steve Palincsar
On Sat, 2013-01-05 at 12:52 -0800, Scot Brooks wrote: > Patrick, > In my case "all speeds" is really all speeds I ride at which is probably > between 12mph and 20mph or thereabouts. It happens with and without front > load. For instance, my grocery run last weekend was all loaded into my > sadd

Re: [RBW] Re: Shimmy cured

2013-01-05 Thread Scot Brooks
Forgot to describe it; it's a back and forth wobble of maybe 4 or 5 inches total side-to-side movement. Maybe more. It doesn't get any more or less pronounced at different speeds that I can tell but the frequency gets a little scary when I'm going quickly. -- You received this message because

Re: [RBW] Re: Shimmy cured

2013-01-05 Thread Scot Brooks
Patrick, In my case "all speeds" is really all speeds I ride at which is probably between 12mph and 20mph or thereabouts. It happens with and without front load. For instance, my grocery run last weekend was all loaded into my saddlesack, but this weekend I split it up between the saddlesack an

Re: [RBW] Re: Shimmy cured

2013-01-05 Thread PATRICK MOORE
"at all speeds." This is very strange. Can you describe the "feeling" of the shimmy you experience? Usually shimmy occurs at very distinct speed ranges; for example, I once experienced it on my '95 custom at just under 20 mph. I had ridden the bike for Ks of miles and never had shimmy, until the sh

[RBW] Re: Shimmy cured

2013-01-05 Thread Scot Brooks
Great timing for this topic since I've noticed my Sam/Surly Rack/Saddlesack Large combo makes for a bike that has pretty extreme shimmy at nearly all speeds. With the bike stripped I can ride as long as I please no-handed but its a hairy proposition with the rack and bag, even without a load.

[RBW] Re: Shimmy cured

2013-01-05 Thread William
For folks considering 1" threaded roller bearing headsets in general, there is also a Miche offering that QBP sells, meaning any LBS can order for you. That has rollers top and bottom. On Saturday, January 5, 2013 9:45:48 AM UTC-8, BSWP wrote: > > I note that the RBW Tange/IRD setup has needl

[RBW] Re: Shimmy cured

2013-01-05 Thread BSWP
I note that the RBW Tange/IRD setup has needle bearings at bottom, and ball bearings at top. Most of us considering switching to roller bearings for added damping, I would suppose, already have ball bearings both top and bottom. So why not replace just the bottom bearing? It must be industry pr

Re: [RBW] Re: Shimmy cured

2013-01-05 Thread Steve Palincsar
On Fri, 2013-01-04 at 20:51 -0800, allenmichael wrote: > Probably too much to hope for that it will also quiet the front-wheel > dive at low speeds going uphill with a front load (which was much > better on second tour with less weight placed lower in the front), but > i'm still wanting to try it o

[RBW] Re: Shimmy cured

2013-01-04 Thread allenmichael
After reading this post, I stopped at my local bike shop to inquire about the price for installing a new headset, $30. Might be a Feb., pre-summer tour, purchase. I've experienced a shimmy at times with my 56 Atlantis, and I'm sure the headset is aged at this point. Probably too much to hope for

Re: [RBW] Re: Shimmy cured

2013-01-04 Thread Peter Morgano
I tried that but then I just got "notchiness" which was aggravating for the whole trip. On Fri, Jan 4, 2013 at 10:49 AM, mikel66...@juno.com wrote: > has anybody tried overtightening their headset to replicate 'roller > bearing drag' which seems to cure shimmy? > > mike goldman > > warwick,r.i. >

Re: [RBW] Re: Shimmy cured

2013-01-04 Thread mikel66...@juno.com
has anybody tried overtightening their headset to replicate 'roller bearing drag' which seems to cure shimmy? mike goldman warwick,r.i. Woman is 53 But Looks 25 Mom reveals 1 simple wrinkle trick that has angered doctors... http://thirdp

[RBW] Re: Shimmy cured

2013-01-04 Thread Mike
Thanks for the info Doug. I have experienced a bit of shimmy on my Hilsen. I didn't notice the RBW was now selling the IRD headset. Here's a link to it. http://www.rivbike.com/product-p/hsrd.htm --mike -- You received this message because you are subscribed to the Google Groups "RBW Owners B

[RBW] Re: Shimmy, according to BQ

2011-01-07 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-22 Thread doug peterson
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

[RBW] Re: Shimmy, according to BQ

2010-12-22 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-22 Thread Philip Williamson
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread Tim McNamara
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-21 Thread Rene Sterental
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread neurodrum
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,

Re: [RBW] Re: Shimmy, according to BQ

2010-12-21 Thread andrew hill
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread doug peterson
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread Michael_S
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-21 Thread Steve Palincsar
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread William
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-21 Thread james black
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread doug peterson
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

[RBW] Re: Shimmy, according to BQ

2010-12-21 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-20 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-20 Thread Bill
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

[RBW] Re: Shimmy, according to BQ

2010-12-13 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-13 Thread William
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-13 Thread Seth Vidal
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-13 Thread james black
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

[RBW] Re: Shimmy, according to BQ

2010-12-13 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-13 Thread EricP
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

Re: [RBW] Re: Shimmy, according to BQ NRC

2010-12-13 Thread zeidler . robert
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

[RBW] Re: Shimmy, according to BQ NRC

2010-12-12 Thread Bill M.
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

[RBW] Re: Shimmy, according to BQ

2010-12-12 Thread Kelly
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

[RBW] Re: Shimmy, according to BQ

2010-12-12 Thread EricP
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

[RBW] Re: Shimmy, according to BQ NRC

2010-12-12 Thread Jim Cloud
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

Re: [RBW] Re: Shimmy, according to BQ NRC

2010-12-12 Thread Steve Palincsar
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

Re: [RBW] Re: Shimmy, according to BQ NRC

2010-12-12 Thread Robert Zeidler
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

Re: [RBW] Re: Shimmy, according to BQ NRC

2010-12-12 Thread Bill Gibson
> 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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-12 Thread Ken Freeman
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

[RBW] Re: Shimmy, according to BQ NRC

2010-12-12 Thread Jim Cloud
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

[RBW] Re: Shimmy, according to BQ

2010-12-12 Thread Kelly
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

[RBW] Re: Shimmy, according to BQ

2010-12-12 Thread Montclair BobbyB
... 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

[RBW] Re: Shimmy, according to BQ

2010-12-11 Thread hobie
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

[RBW] Re: Shimmy, according to BQ

2010-12-11 Thread Kelly
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

[RBW] Re: Shimmy, according to BQ

2010-12-11 Thread Bill M.
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

[RBW] Re: Shimmy, according to BQ

2010-12-11 Thread EricP
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.

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Jan Heine
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Jan Heine
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread doug peterson
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread cyclotour...@gmail.com
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread William
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Clayton Scott
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-10 Thread BPustow
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:

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread MichaelH
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Montclair BobbyB
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Allan in Portland
> 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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Michael_S
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread stevep33
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Allan in Portland
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Steve Palincsar
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread William
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread newenglandbike
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

Re: [RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Steve Palincsar
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

[RBW] Re: Shimmy, according to BQ

2010-12-10 Thread Jan Heine
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

[RBW] Re: Shimmy!

2010-08-12 Thread rb
Make sure that the handlebar bag is fastened down at the front of the rack as well as being cinched between the decaleur (if there is one) and the rear of the rack. If there is only one attachment plane, shimmy is easy to get from the small sway of the bag at speed. On Aug 9, 12:15 pm, Rene Stere

[RBW] Re: Shimmy!

2010-08-10 Thread Philip Williamson
This was an interesting thread; it got me to try out some shimmy for myself. I've never experienced speed wobble or shimmy before. Riding the Quickbeam on a flat road at about 14 mph, with 40mm tires and 8-10 lbs in a front bag, I sat up no-hands and whacked the handlebars sideways. Bwo-wo-wo-wo-w

Re: [RBW] Re: Shimmy!

2010-08-10 Thread Rene Sterental
Thanks for setting me straight again! :-) I obviously missed the beginning of the thread. My apologies to the OP... :-) René On 8/10/10, CycloFiend wrote: > on 8/10/10 4:38 AM, Rene Sterental at orthie...@gmail.com wrote: > >> Here's why I made my assumption: >> >> "i tense up and apply the bra

Re: [RBW] Re: Shimmy!

2010-08-10 Thread CycloFiend
on 8/10/10 4:38 AM, Rene Sterental at orthie...@gmail.com wrote: > Here's why I made my assumption: > > "i tense up and apply the brakes a little..." (snipped) That was a follow up post made by Bob C. Not the original post. Further, I'm not quite sure why this was referenced to Angus' Quickbea

Re: [RBW] Re: Shimmy!

2010-08-10 Thread Rene Sterental
Here's why I made my assumption: "i tense up and apply the brakes a little. I sit down reflexively to lower my center of gravity, which we all do when it looks like we are going to fall. To not do this requires extraordinary will power and confidence. Instantly, your Quickbeam starts to shake vio

[RBW] Re: Shimmy!

2010-08-09 Thread MichaelH
Actually, I said no such thing. I wrote that I was going 45 mph and moved from the drops to the tops & a tuck when the slight vibration started. I immediately reverted to the drops & the vibration stopped. Thanks for the reference to the ibob, discusiion & Brandt's thoughts. The thing that mos

Re: [RBW] Re: Shimmy!

2010-08-09 Thread Rene Sterental
I guess that's the best way to get rid of it! :-) Thanks for the emergency solution! René -- 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 grou

Re: [RBW] Re: Shimmy!

2010-08-09 Thread Steve Palincsar
On Mon, 2010-08-09 at 17:28 -0500, Rene Sterental wrote: > You're correct. My confusion. It's just that the OP stated that at > speed he'd see a bump or something, would tense and hit the brakes and > the vibrations would start; it threw me off. > > This is quite an interesting discussion but seei

Re: [RBW] Re: Shimmy!

2010-08-09 Thread Rene Sterental
You're correct. My confusion. It's just that the OP stated that at speed he'd see a bump or something, would tense and hit the brakes and the vibrations would start; it threw me off. This is quite an interesting discussion but seeing as there is no cure and it's just another bike trait to understa

Re: [RBW] Re: Shimmy!

2010-08-09 Thread CycloFiend
on 8/9/10 9:15 AM, Rene Sterental at orthie...@gmail.com wrote: > Does this only happen when you brake and goes away if you stop braking? > > Does I happen in bikes with canti brakes but not on bikes with sidepull > brakes? > > I've had this problem only on a Gunnar with canti brakes. Have yet t

Re: [RBW] Re: Shimmy!

2010-08-09 Thread james black
On Mon, Aug 9, 2010 at 10:32, Bob Cooper wrote: > Jobst is the only person who has shed enough light on this problem of > mine that, when I actually apply his advise, it has an effect. All > praise to Jobst for that post to the FAQ all those years ago. > http://sheldonbrown.com/brandt/shimmy.html

[RBW] Re: Shimmy!

2010-08-09 Thread Bob Cooper
René, Thanks for the comments. However, I doubt that brake design has much of an effect on shimmy. By the way, here I define “shimmy” as a mind-numbing terror at an oscillation of maybe 120 cycles per second and an imminent crash. “Shimmy” sounds like a silly dance that they did in the 1920s, but

Re: [RBW] Re: Shimmy!

2010-08-09 Thread Steve Palincsar
On Mon, 2010-08-09 at 08:44 -0700, Bob Cooper wrote: > It’s a cold, sunny spring morning, and I’m shivering slightly. That right there is enough to initiate a shimmy. > I hit a bump in the road hidden by a shadow from a tree. > > I tense up And per the FAQ that itself is a contributing factor

Re: [RBW] Re: Shimmy!

2010-08-09 Thread Rene Sterental
Does this only happen when you brake and goes away if you stop braking? Does I happen in bikes with canti brakes but not on bikes with sidepull brakes? I've had this problem only on a Gunnar with canti brakes. Have yet to descend fast on the Atlantis to see if it will happen. Front cantilever bra

[RBW] Re: Shimmy!

2010-08-09 Thread Bob Cooper
Hello Angus, et al, The scenario is this: I’m riding Angus’ Quickbeam down Italy Turnpike outside Naples, New York. Your Quickbeam has just been serviced by a great mechanic. The frame is straight; the wheels are perfect; the tires are perfect; this headset is perfect. By coincidence, the fit is

Re: [RBW] Re: Shimmy!

2010-08-09 Thread CycloFiend
on 8/8/10 12:21 PM, MichaelH at mhech...@gmail.com wrote: > Up till yesterday the Rambouillet has had > impeccable road manners. I don't think I would buy a second bike from > someone who had sold me a frame with built in shimmy. True shimmy is a reproduceable event. There is typically a speci

Re: [RBW] Re: Shimmy!

2010-08-09 Thread CycloFiend
on 8/8/10 4:12 AM, MichaelH at mhech...@gmail.com wrote: > > Lots of interesting thoughts and suggestions here. I haven't heard > from anyone who thinks the very narrow tires might have contributed to > it. Tires can definitely be a factor. Ride buddy JimG had consistent shimmy issues on his K

[RBW] Re: Shimmy!

2010-08-08 Thread Angus
I rode the Quickbeam this morning, I have not had the bike shimmy before so I tried all sorts of things to see if I could get it to shimmy. If I rode no-handed and leaned back in the seat (very little weight on the front end) it could get a light shimmy. Any movement forward or touching the top

Re: [RBW] Re: Shimmy!

2010-08-08 Thread Steve Palincsar
On Sun, 2010-08-08 at 15:31 -0700, Bob Cooper wrote: > If I have ten bikes and they all shimmy, and Rider X has ten bikes and > none of them shimmy, I think this points in this direction: > > It’s the rider, not the bike. Certainly, rider actions can initiate or exacerbate a bike's tendency to s

[RBW] Re: Shimmy!

2010-08-08 Thread Bob Cooper
If I have ten bikes and they all shimmy, and Rider X has ten bikes and none of them shimmy, I think this points in this direction: It’s the rider, not the bike. How else can it be explained? Bob Cooper On Aug 8, 3:15 pm, rob markwardt wrote: > Funny.  I've had well over 20 bikes, all largish,

[RBW] Re: Shimmy!

2010-08-08 Thread MichaelH
I have(or had) a Rambouillet, a Marinoni, a Soma, Bilenkey, two treks, and an Ebisu. The only one that shimmies is the ebisu and then only when I let go of the handlebars completely. I am not accustomed to bikes that either shimmy or slide sideways. In 30+ tears of riding I have lifted the rear

[RBW] Re: Shimmy!

2010-08-08 Thread rob markwardt
Funny. I've had well over 20 bikes, all largish, and have never experienced any shimmy. That being said I have zero desire to go faster than 45mph. On Aug 8, 7:46 am, Bob Cooper wrote: > Some data points: > > I have a Rivendell Road Custom, a Rambouillet, an Atlantis, two Miyata > Exercisers, a

[RBW] Re: Shimmy!

2010-08-08 Thread Will
<> A mixture of 700cx35mm Continental Top Touring for loaded tours and Michelin Axial Pro 700x23 for Centuries, riding with the club, etc. For the past 2 years I've discovered that 700x33. Jack Brown Greens serve both purposes. Bike feels equally stable with all of 'em, but even more stable w

[RBW] Re: Shimmy!

2010-08-08 Thread Bob Cooper
Some data points: I have a Rivendell Road Custom, a Rambouillet, an Atlantis, two Miyata Exercisers, a Miyata Road Gentleman, four Raleighs and a Peugeot PX-10. They all shimmy. For what it’s worth, Bob Cooper -- You received this message because you are subscribed to the Google Groups "RBW

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