The S-word

[Kevin M]

-SHIMMY

Any Rambler riders dealt with and cured shimmy?

I'm feeling two discinct shimmies: a traditional oscillation when riding no-handed above 16mph, and what I'd call a micro-shimmy.

I feel the micro shimmy when putting in hard efforts, climbing or just hammering it. It feels like it's in relation to the BB flex, as the bike will just walks back and forth in sync with my pedal stroke.

I'm considering changing my headset, but the Cane Creek is just too sweet.

-kevin
In Madison,WI

[Ryan Watson]

My 57 650B Rambler hasn't shimmied once.
I'm using a Stronglight needle bearing headset.

Ryan

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[doug...@gmail.com]

Kevin:

I've only test ridden a Rambler so no experience with shimmy on one.  However, I have a 58 cm Rivendell Atlantis that shimmied under certain conditions.  It now has a Tom Matchak fork that is similar in geo to the Rambler plus a Tange needlebearing headset.  While significantly reduced, it can be made to shimmy by sitting upright while riding no-hands.  Clamping the top tube with my knees or leaning forward eliminates the shimmy.

One thing I learned while playing around before changing the fork was that load placement seems important.  The Atlantis is made of larger, heavier tubing than  the Rambler, and is sold as purpose built touring bike.  With a rear load, say 25 lbs, shimmy happened even when holding the bars, at certain speeds.  Moving that same load to the front eliminated shimmy.  Upping the load to 40 lbs (4 panniers), a moderate rear bias shimmied while a moderate front bias was stable. 

I would suggest experiments with load placement to start.  When I experimented with my Atlantis, I could get shimmy with just a saddlebag with less than 10 lbs, if I sat up going downhill no-hands.  Another consideration is how how secure any load is.  I use a front bag and have experienced shimmy, even now, if I have something heavy in the bag that can move around. 

Good luck.  I'm sure it's a problem than can be reduced to a tolerable level. 

Doug Peterson

[Jason L. Ferrier]

Doug rode my 57cm Rambler, which does have a tiny bit of shimmy in certain circumstances.

Pink Chris King headset, drop bars, Nitto Mark's rack, Docena up front.  I find that when there is almost no load in the front and I am riding upright/no-hands on flats it starts to shimmy a tiny bit.  As soon as I get some weight back up front it is fine.

I have not checked my headset tightness since I built the bike almost four years ago, so it's probably about time to tear it down, re-grease things and check all the bolts.

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[Thomas Bielavitz]

I have a 700c, and have never experienced shimmy with or without front loads (usually a Docena but also w/ Docena + panniers, 35lbs total). I'm using a King HS. 

I can make it shimmy by riding one-handed and pedaling hard, or no-handed at moderate speeds (as Kevin mentions) but I consider that my own fault. 

On Sunday, May 21, 2017 at 5:50:22 AM UTC-7, Kevin M wrote:

[Kevin M]

Well, since this is the only bike I've had that shimmies when I ride no-handed, I wouldn't consider that my own fault. I don't understand your reasoning...

I like riding no handed when I'm changing in/out of a rain shell, peeling off some layers, or snacking. The convenience of having all the stuff in accessible in a rando bag is one of the reasons why I chose the Rambler. 

[doug...@gmail.com]

Kevin:

When you get the oscillation you mention in your post, what do you do to correct it? 

Agree that carrying a front load is a compelling reason for a Rambler.  Like you, I also like having my goodies right handy.  With the stock fork on my Atlantis, it tended to wander when climbing at low speed.  The custom fork cured that.  I think my fork and the Rambler are quite similar. 

doug

[Jason L. Ferrier]

The easiest way I have found to stop the oscillation is to touch the top tube however you'd like. While coasting I touch my knee to it, grab it with my hand or whatever - it stops immediately.

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[doug...@gmail.com]

Even with all the futzing around I've done, I still get the odd shimmy at various times.  That's what I do as well.  Seems as if damping the top tube is the easy answer. 

doug

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[John Bokman]

Kevin:

I have a 700c Rambler that shimmied every time I sat up no handed. Happened at slow speed (sub 10mph) or moderate speed (10-20 mph). It was alarming. I already had a needle bearing headset (Miche), but I did have my mechanic tighten it. Still, after the tightening, I could produce the shimmy at will, in the same way: upright, no-handed.

Because I've encountered shimmy before on a different bike, my belief is that, at least for me (tall, skinny, light rider), shimmy has more to do with my body weight, and how I weight the bike, than any other single factor. I say this because i could get shimmy going with a front bag, or no front bag. On another of my bikes that displayed shimmy, I could get it going with or without  a load, also.

So what I did, was change my positioning on the bike. By simply moving my saddle every so slightly forward (toward the bottom bracket), maybe a centimeter at most, I stopped the shimmy. It has not returned. Interestingly, I've been playing around with my positioning since trying to switch from clipless to flat pedaling. I find that on flats, I want to be seated further back from the bottom bracket. For whatever reason, even though I've moved the saddle back, the shimmy has not returned! But i do think if I work hard enough at it, I will be able to reproduce it. So I'm not going to try too hard.

Moral of the story: How I weight the bike matters more than any other single factor (and I believe this to be the case  whether on my Rambler or my mid-trail, touring bike).

On Sunday, May 21, 2017 at 5:50:22 AM UTC-7, Kevin M wrote: