I found that with the homer + mark's rack + basket load, if I didn't add a second set of struts to the rack, I'd get these harmonic movements that got really nerve wracking on decents, etc. Sort of solved it by either
1) irish strapping rack to the handlebars 2) replacing with big front rack On my low trail chicken, with heavy loads I also get oscillating movement, but we're talking tens of pounds here, like two cases of beer territory; I often clamp the top tube with my legs and I it calms it down--in this case I can definitely see the flexing of the tubes as this happens. cc On Fri, May 29, 2015 at 5:01 PM, cyclotourist <cyclotour...@gmail.com> wrote: > Thanks Doug! Last weekend would have been a good time to talk about > this, but too busy scraping off the mud! :-) > I only had the one pannier this time, so figure that could be a > contributing factor. Although last time I had two, with same effect. > Hands-free isn't the absolute goal, but riding with a light touch > would be nice! I get death-shimmy at even real low speeds if I let go > of the bars, and a minor one if I use one hand light. Gotta' be a > better way! > > On Fri, May 29, 2015 at 4:32 PM, dougP <dougpn...@cox.net> wrote: > > David: > > > > As you can see, there is no single answer to the shimmy problem. > > Personally, I think where the load is, both front / rear and high / low) > and > > how each of us rides are major factors. A good example is Joe Bartoe's > > experience with shimmy on his Hilsen with a light front load, whereas my > > Atlantis will shimmy with a lightly loaded rear saddlebag but moving that > > bag to the front solves the problem. Atlantis & Homer are different > bikes, > > and Joe & I are different sizes and likely riding styles. > > > > As to solving the puzzle, I found a gentle hill that allowed the bike > roll > > up to about 20 mph w/o pedaling (pedaling seems to dampen things for > me). I > > took 4 panniers loaded with books to simulate the weight of my gear, and > > tried all front, all rear, some front, some rear, etc., until I found a > > combination that was rock solid. What works for me is 60% of the weight > in > > front & 40% rear. For an S240 or a loding tour, I only need 2 bags so > they > > both go on the front. In the photo, I don't recall what was in the > saddle > > bag but it was probably a last minute add for overflow, and the sleeping > pad > > hanging off the back can't weight much. > > > > To avoid buying new stuff for only a few trips per year, take what you've > > got & find a similar hill and experiment. I think the no-hands is > asking a > > lot but I grant you should be able to ride the bike light handed & not > in a > > death grep. Seriously try putting some heavy stuff in the basket BUT > make > > sure it can't shift or bounce around. I had some dive weights in my > Acorn > > bag on time (they would let us drive tent stakes) and got shimmy for > shimmy > > (probably had 12 lbs of lead). > > > > Location is another variable. Weight up high (basket, rando bag, etc.) > > seems to be shimmy enabling. If you can't come up with a non-shimmy > > combination with your existing rackage, you may have to look at low > riders. > > IMHO getting the weight centered around the front axle seems to improve > life > > greatly. I've used my big Ortleibs on my Tubus Duo front rack and it's > rock > > solid. > > > > Another consideration that's been mentioned is the roller bearing headset > > that Riv sells. I've got one on my Atlantis and have not had any shimmy > > since installing. But then before that I'd worked around the shimmy with > > loading so it can't be credited entirely. But it's still worth a > thought. > > > > Lastly, and probably heresay here, but I've had situations where I know > the > > Nitto Big Back rack was contributing to handling difficulties, albeit > likely > > overloaded by their standards. As beautiful as they are, they lack > lateral > > triangulation and can develop resonance. Tubus and other rack makers > design > > with a triangle, viewed from the rear, that greatly stiffens the > structure. > > The Nitto R-26 (?) that I had for while is essentially a pyramid, is made > > out of 10 mm tubing, and is as stiff as they come. Unfortunately the > > platform was a little small for my needs. > > > > On our next S24O, I'll throw all my junk on the back to see how things > work > > with Tubus rack since I got the needle bearing headset. The downside to > > front low riders is limited clearance. > > > > dougP > > > > On Thursday, May 28, 2015 at 9:27:05 PM UTC-7, cyclot...@gmail.com > wrote: > >> > >> It took me a sec to find a photo, but it handled just as terribly when > >> it was straight rear-loaded with nothing on front. You can see it on > >> the right in this photo, with both panniers in place and packed full: > >> https://www.flickr.com/photos/cyclotourist/15187812094 > >> So basically two panniers full + tent in back = bad > >> One pannier + tent in back with light load on front = bad > >> Is there a magic way to load this that makes it pleasant to ride? I > >> know it's not a loaded touring bike, but hoping for at least a little > >> stability whilst loaded and not crazy shimmy all over the road. > >> > >> On Thu, May 28, 2015 at 9:11 PM, Joe Bartoe <jba...@hotmail.com> wrote: > >> > David, > >> > > >> > My experience with a Hilsen with small front rack and small front bag > on > >> > it, > >> > indicates that Riv-designed bikes are not really good handlers with > >> > front > >> > loads. It shimmied like crazy! The other items may have contributed, > but > >> > my > >> > guess is the stuff on the front had more to do with the shimmy. > >> > > >> > Joe > >> > > >> > Joe Bartoe > >> > Synaptic Cycles Bicycle Rentals, Inc. > >> > email: j...@synapticcycles.com > >> > website: www.synapticcycles.com > >> > Twitter: @synapticcycles > >> > phone: 949-374-6079 > >> > > >> > > >> > -- > >> > 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-bun...@googlegroups.com. > >> > To post to this group, send email to rbw-owne...@googlegroups.com. > >> > Visit this group at http://groups.google.com/group/rbw-owners-bunch. > >> > For more options, visit https://groups.google.com/d/optout. > >> > >> > >> > >> -- > >> 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. > > > > -- > 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. > -- "I want the kind of six pack you can't drink." -- Micah -- 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.
