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 on smooth flat road it shimmies about 3/4" amplitude at the stem bolt at about 4Hz. Putting a knee on the top tube stops it. I wanted to start with things that I can change for free on the bike and see how that affects shimmy.
Test 1: Pump up front tire (Jack Brown blue) from 30psi to 70psi. Result--no change. Still shimmies at will Test 2: Pump up rear tire (JB blue) from 30psi to 70psi. Result--no change. Still shimmies exactly the same Test 3: Remove Trunksack and contents from front of bike (3-4lbs of weight). Result--no change. Still shimmies easily, same amplitude, same frequency as far as I can tell Test 4: Remove Saddlesack Large and contents from the back (10-12lbs of weight). Result--shimmy GONE. I can't get it to move at all I'm going to start adding weight back on to the bike, beginning with the front. I'll keep experimenting. 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 configure this bike differently. If I choose to configure my bike this way, I should be prepared to accept some shimmy. Jan's article encouraged me to experiment, and I've started doing that, and I'm learning more about my bike, and that's all good stuff. On Dec 13, 3:09 am, EricP <ericpl...@aol.com> wrote: > 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 riding > this weekend. We received 17 inches in the latest storm. Side roads > are still unplowed or at best two cars wide. With very compacted > snow. For me, that's scary. > > Eric Platt > St. Paul, MN > > On Dec 12, 10:06 pm, Kelly <tkslee...@gmail.com> wrote: > > > 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 reason to sell the race bike and get the ahh.. :) > > > But then the ride to starbucks and walgreens today was just as scary > > as that speed > > :)http://www.flickr.com/photos/tksleeper/sets/72157625582548862/ > > > Kelly > > -- 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, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
