Re: [RBW] Re: Front end shimmy.
I don't have an Atlantis, but I've experienced shimmy on 2 of my Riv
customs (not on a 3d), both times starting to appear after years/miles of
riding them without a sign of the problem.
I have no idea what caused it, but among things that I did change " the
problem appeared were tires: from Turbos to Kojaks on the '03; from Paellas
to Turbos on the '94.
Other things that changed: Saddle ('94; Pro to Flite); fenders ('94, none
to some, Berthoud); drivetrain (both; free to fixed); dyne hubs ('94: none
to SON 28 to none; '03: non to SON 20R); and so on and so on.
Point being that, IME, any of a myriad of apparently little and apparently
very tenuously related things can cause it. I don't have shimmy on the
gofast.
It's not a huge problem for me, since I rarely ride no-hands.
What *I* want to know is how to stop cold weather squealing on salmon pads
...
On Sun, Feb 8, 2015 at 8:59 AM, Andy.M wrote:
> Doug and I have talked about shimmy a bit involving our respective Atlanti
> (mine is a 56cm with 26" wheels) and it seemed that in both our experience
> that a high rear load equates to a shimmy. To me, when loaded, the
> Atlantis rides the most stable with a low front load. For overnighters I
> usually keep the big saddle bag on the rear rack (which is there
> permanently and I deal with the slight shimmy if I make a big market trip)
> and front paniers. With more low weight in the front the ride is smooth as
> glass.
> -Andy
>
> On Saturday, February 7, 2015 at 4:22:10 PM UTC-8, hsmitham wrote:
>>
>> I'm on a roll here with another question!!
>>
>> On my Atlantis with about 5 to 6 lb load up front I have noticed the
>> front end shimmy with no hands (I realize that Riv say's or thinks I'm a
>> knuckle head for this practice) which is for only a brief time period, even
>> with one hand I can feel the and see the shimmy which is pretty violent
>> above 19-20 MPH so much so that lister Mike S. commented on it. Mike and
>> Riv claim that others have experienced the same and switched to the Tange
>> needle bearing headset resolving the issue.
>>
>> My question, has anyone out there experienced this phenomenon? And if so
>> did you switch to the Tange needle bearing headset and did it resolve the
>> shimmy or at the least reduce it. What Riv say's about more friction at the
>> lower race where all the force is received makes sense? I'd just like some
>> real world application confirmation. 'nough said.
>>
>> Thanks in advance for you experiences and feedback.
>>
>> ~Hugh
>> Los Angeles, CA
>>
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[RBW] Re: Front end shimmy.
On Saturday, February 7, 2015 at 7:07:21 PM UTC-6, dougP wrote: > > Hugh: > > I've had shimmies with my 58cm Atlantis. Oddly enough, and contrary to > accepted wisdom, mine was induced by a moderate rear load. > +1. That has been my experience, too, on Heron Road bikes (700C as spec'd and 650B converted), Quickbeam, and Bleriot Protovelo. I recently mounted a Tubus Targa low rider rack on my Protovelo and did my usual commute with front panniers instead of my typical Lowsaddle Longflap / Boxy Bag handlebar combo (most the weight in the saddle bag). The handling was remarkably improved. The very shallow head angle of the Bleriot creates a large amount of wheel flop. Low mounted panniers had an amazing dampening effect. It's hard for me to wrap my head around the notion that 10-20 extra pounds on the saddle could induce shimmy. If it was just that, then someone 10-20 pounds heavier than I am should create the same effect. So, I hypothesize it has something to do with the saddlebag load not being firmly attached. Physicists feel free to pile on. Ted Durant -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
Re: [RBW] Re: Front end shimmy.
A needle bearing headset seems to help with shimmy but isn't a cure all. I experienced a violent shimmy even with this headset. I was riding downhill and hit a patch of sand on the asphalt. It was a OMG, I sure I'm gonna wreck, experience. I was lucky and rode out the shimmy. Afterwards I stopped to compose myself and to check the bike out.I was sure something was seriously wrong, but couldn't find anything. While it was happening I thought for sure a tire had blown out, but my tire pressure seemed fine. I tightened the headset a little, counted my blessings, and rode home. The bike I was riding has standard diameter, thin-walled tubing and is optimized for carrying a load up front. My Acorn Boxy Rando bag was carrying about 6lb. I haven't experienced front end shimmy since. Hope I never do. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
[RBW] Re: Front end shimmy.
Doug and I have talked about shimmy a bit involving our respective Atlanti (mine is a 56cm with 26" wheels) and it seemed that in both our experience that a high rear load equates to a shimmy. To me, when loaded, the Atlantis rides the most stable with a low front load. For overnighters I usually keep the big saddle bag on the rear rack (which is there permanently and I deal with the slight shimmy if I make a big market trip) and front paniers. With more low weight in the front the ride is smooth as glass. -Andy On Saturday, February 7, 2015 at 4:22:10 PM UTC-8, hsmitham wrote: > > I'm on a roll here with another question!! > > On my Atlantis with about 5 to 6 lb load up front I have noticed the front > end shimmy with no hands (I realize that Riv say's or thinks I'm a knuckle > head for this practice) which is for only a brief time period, even with > one hand I can feel the and see the shimmy which is pretty violent above > 19-20 MPH so much so that lister Mike S. commented on it. Mike and Riv > claim that others have experienced the same and switched to the Tange > needle bearing headset resolving the issue. > > My question, has anyone out there experienced this phenomenon? And if so > did you switch to the Tange needle bearing headset and did it resolve the > shimmy or at the least reduce it. What Riv say's about more friction at the > lower race where all the force is received makes sense? I'd just like some > real world application confirmation. 'nough said. > > Thanks in advance for you experiences and feedback. > > ~Hugh > Los Angeles, CA > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
Re: [RBW] Re: Front end shimmy.
Needle bearing headset has cured shimmies on 2 bicycles I have owned. I use Miche. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
Re: [RBW] Re: Front end shimmy.
Doug, Your right it's a relatively inexpensive experiment and one I'll most likely do. You know the shimmy did happen when I had a rear and front load, so maybe I can't blame it all on a front load? I was carrying about 20# in the rear so perhaps it's just the fact that I have about 25# total plus my 160# could account for the shimmy. That much weight being delivered to the bottom race, if there's any movement/ slop down there then it's conceivable to get the pronounced effect. I'd still welcome other's with a similar experience to chime it. Did going with the Tange HS solve your shimmy issue? ~Hugh Los Angeles, CA ~Hugh “Life is like riding a bicycle. To keep your balance, you must keep moving.” ― Albert Einstein http://velocipedemusings.blogspot.com/ On Sat, Feb 7, 2015 at 5:07 PM, dougP wrote: > Hugh: > > I've had shimmies with my 58cm Atlantis. Oddly enough, and contrary to > accepted wisdom, mine was induced by a moderate rear load. I used to use a > Rivendell Hobo bag as a saddle bag. On a gradual downhill near where I > live, with a modest amount of weight (a few pounds) in the saddlebag, > coasting and sitting upright the bike would shimmy predictably at about 12 > mph. Switching the bag to the handlebars (it's designed to mount either > way eliminated the shimmy. This is with the stock Ultegra headset. To > shimmy, I had to sit bolt upright without touching the bars. Even leaning > forward would eliminate it and holding the bars anywhere would stop it. > > With panniers I found that more weight on the rear than front would lead > to shimmy. With more weight on the front, even shaking the bars would not > start a shimmy. So I just rode the bike front loaded for a few years and > only experienced one shimmy and that involved a lot of wind and long > downhill. > > A couple of years ago I changed to the Tange headset, but it was at the > same time I changed to the lower trail fork, so it's not clear what impact > each of those may have had on the shimmy issue. I have not experienced any > shimmy since then but then I hadn't had much of a problem as long as I was > front loaded either. > > Of course that's entirely at odds with your experience with front > loading. The Tange headset could certainly be helpful by adding some > friction. Jan Heine / Bicycle Quarterly has written a lot about the shimmy > issue but concluded it's pretty unpredictable, although they also recommend > roller bearing headsets as one thing to try. > > If you have a shimmy inducing amount of weight in your basket, what > happens if you take that same weight in low riding panniers on the front? > Personally I think weight high up has more effect on handling than weight > down low. When you think about it, the bicycle rotates about the steering > axis so the closer the weight to that plane the better for handling. The > opposite would be to place a lot of weight way back on the rear of the > bike, a long way from the pivot point. > > The Tange headset is a pretty cost effective experiment. I had mine > installed at my LBS & I think it was in the $100 range for parts & labor. > The original one was probably OK but it was 10 years old. > > dougP > > > On Saturday, February 7, 2015 at 4:22:10 PM UTC-8, hsmitham wrote: >> >> I'm on a roll here with another question!! >> >> On my Atlantis with about 5 to 6 lb load up front I have noticed the >> front end shimmy with no hands (I realize that Riv say's or thinks I'm a >> knuckle head for this practice) which is for only a brief time period, even >> with one hand I can feel the and see the shimmy which is pretty violent >> above 19-20 MPH so much so that lister Mike S. commented on it. Mike and >> Riv claim that others have experienced the same and switched to the Tange >> needle bearing headset resolving the issue. >> >> My question, has anyone out there experienced this phenomenon? And if so >> did you switch to the Tange needle bearing headset and did it resolve the >> shimmy or at the least reduce it. What Riv say's about more friction at the >> lower race where all the force is received makes sense? I'd just like some >> real world application confirmation. 'nough said. >> >> Thanks in advance for you experiences and feedback. >> >> ~Hugh >> Los Angeles, CA >> > -- > You received this message because you are subscribed to a topic in the > Google Groups "RBW Owners Bunch" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/rbw-owners-bunch/HZBWIzj1Y0U/unsubscribe > . > To unsubscribe from this group and all its topics, send an email to > rbw-owners-bunch+unsubscr...@googlegroups.com. > To post to this group, send email to rbw-owners-bunch@googlegroups.com. > Visit this group at http://groups.google.com/group/rbw-owners-bunch. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group
[RBW] Re: Front end shimmy.
Hugh: I've had shimmies with my 58cm Atlantis. Oddly enough, and contrary to accepted wisdom, mine was induced by a moderate rear load. I used to use a Rivendell Hobo bag as a saddle bag. On a gradual downhill near where I live, with a modest amount of weight (a few pounds) in the saddlebag, coasting and sitting upright the bike would shimmy predictably at about 12 mph. Switching the bag to the handlebars (it's designed to mount either way eliminated the shimmy. This is with the stock Ultegra headset. To shimmy, I had to sit bolt upright without touching the bars. Even leaning forward would eliminate it and holding the bars anywhere would stop it. With panniers I found that more weight on the rear than front would lead to shimmy. With more weight on the front, even shaking the bars would not start a shimmy. So I just rode the bike front loaded for a few years and only experienced one shimmy and that involved a lot of wind and long downhill. A couple of years ago I changed to the Tange headset, but it was at the same time I changed to the lower trail fork, so it's not clear what impact each of those may have had on the shimmy issue. I have not experienced any shimmy since then but then I hadn't had much of a problem as long as I was front loaded either. Of course that's entirely at odds with your experience with front loading. The Tange headset could certainly be helpful by adding some friction. Jan Heine / Bicycle Quarterly has written a lot about the shimmy issue but concluded it's pretty unpredictable, although they also recommend roller bearing headsets as one thing to try. If you have a shimmy inducing amount of weight in your basket, what happens if you take that same weight in low riding panniers on the front? Personally I think weight high up has more effect on handling than weight down low. When you think about it, the bicycle rotates about the steering axis so the closer the weight to that plane the better for handling. The opposite would be to place a lot of weight way back on the rear of the bike, a long way from the pivot point. The Tange headset is a pretty cost effective experiment. I had mine installed at my LBS & I think it was in the $100 range for parts & labor. The original one was probably OK but it was 10 years old. dougP On Saturday, February 7, 2015 at 4:22:10 PM UTC-8, hsmitham wrote: > > I'm on a roll here with another question!! > > On my Atlantis with about 5 to 6 lb load up front I have noticed the front > end shimmy with no hands (I realize that Riv say's or thinks I'm a knuckle > head for this practice) which is for only a brief time period, even with > one hand I can feel the and see the shimmy which is pretty violent above > 19-20 MPH so much so that lister Mike S. commented on it. Mike and Riv > claim that others have experienced the same and switched to the Tange > needle bearing headset resolving the issue. > > My question, has anyone out there experienced this phenomenon? And if so > did you switch to the Tange needle bearing headset and did it resolve the > shimmy or at the least reduce it. What Riv say's about more friction at the > lower race where all the force is received makes sense? I'd just like some > real world application confirmation. 'nough said. > > Thanks in advance for you experiences and feedback. > > ~Hugh > Los Angeles, CA > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
