Hugh: In the interest of science, further testing required. David & I are contemplating doing some tests with his bike. If we can coordinate it, you might want to join us with your Atlantis. I did not know your Atlantis was also an '03. I would guess ours are from the same batch or really close. My s.n. is 519; take a look under your BB to see what yours is. I have a couple of ideas that may be worth exploring. We're thinking about the weekend of June 14 when REI has their big gear sale in Tustin.
dougP On Sunday, May 31, 2015 at 7:13:17 PM UTC-7, hsmitham wrote: > > Whew! I just read all the posts, took two attempts. I've been busy! > > I have to agree with rack/load flex as at least one point of origin of > oscillation that is then transmitted through out the frame, but in the > extreme. Both my Hilsen and Atlantis have had shimmy. When riding the > Hilsen basically unloaded at speeds above 25 mph hands free I get shimmy as > soon as I squeeze the top tube with my knees it's gone! Hands on nothing. > > I had the same issue with my '03 Atlantis loaded or unloaded. Violent > shimmy even with one hand loaded and horrible at low speed climbing, lots > of drift and correction which is super fatiguing. Mike Schiller suggested > the Tange needle bearing headset, which I installed. The headset made a > huge difference and like Doug said the increased friction at the bottom > race (the upper race are normal bearings)dampens the oscillation. But this > headset will only go so far in resolving shimmy. Personally, I feel that > the ride quality inherent with Riv's tubing and geometry that we admire is > also what contributes to frame flex and consequently shimmy. In the case of > both my bikes unladen I hypothesize the shake originates at the bottom fork > race and becomes amplified though out the frame. Add a load that flexes and > you have a recipe for increased shaking. I understand that some Riv's don't > manifest these qualities therefore I attribute this to inconsistencies in > batch builds. Also, I'm certainly no expert in tubing types and geometry > but understand there are other bike builds that don't manifest these > qualities. But since we're talking about a Riv "All Rounder". > > David, I understand you want to use what you have but I'll still throw out > my suggestions even though. > > So how to mitigate these aspects and have the stability desired? Install > the Tange headset number one, next as Doug mentioned, try different load > configurations. I like a low front load even with a medium trail fork using > a Tubus low rider rack with hoop, small campee rack/basket configuration > under 3 lbs and a light rear load strapped/secured to an R14 rack. When > feasible I ditch the low rider's off road. > > In terms of cockpits, and I know lots of you love drop bars but for > comfort I like Albatross bars up high, I can be in an aggressive position > in the hooks and when I need to give my back and neck a break I can sit up > with no need to ride hands free. > > I have plans to remove & replace my Hilsen's headset and since my Atlantis > is my loaded tour rig I have plans to have a low trail fork built just to > see whether or not it makes a difference. My .02. > > Cheers, > > ~Hugh > Los Angeles, CA > > > > > > May 28, 2015 at 9:07:38 PM UTC-7, cyclot...@gmail.com wrote: > > Last week on a S240, had a great time (except for that one incident) > > but the problem was really, really bad shimmy/wobble. So bad I really > > couldn't take my hands off even for a bit at any speed. > > Rear loaded, with a little bit up front (sleeping bag). Pannier on one > > side only but not a ton of weight in there. Heaviest thing was > > probably the tent, packed up high. > > So what am I packing wrong? I don't want to get a whole new luggage > > system, nor a new bike, just want to work with what I've got and what > > you can see here: > > > https://www.flickr.com/photos/cyclotourist/17795666300/in/photostream/lightbox/ > > > Suggestions? Want to get it so I'm stable and can ride hands free, at > > least at lower <10mph speeds. Possible, or just the wrong bike for it? > > Intermediate Riv tubing, OS downtube, nothing super light, nor super > > stout, basically like a Hilsen I would guess. > > > > -- > > Cheers, > > David > > > > Member, Supreme Council of Cyberspace > > > > "it isn't a contest. Just enjoy the ride." - Seth Vidal > > -- 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.
