Front wheel shimmy has been very curious. I recently built a different front wheel with a Schmidt hub, Mavic Open Pro rim and mounted a Schmidt eDeluxe headlight on my All-Rounder. I used a long aluminum spacer with beveled washers that allow for adjustment in the angle and direction that the light points. I mounted the light to the fork on the non-drive side using the mid-fork braze on. It's a very good position for the light. The same bike with the large Nitto front rack from Rivendell tracks straight as an arrow. This would lead me to believe that there is a "just-wrong" moment with weight, distribution, and tire size.
By more permanent, I mean only that I know which bikes will be set up with dynamo hubs and will always be ready to go. I know that I will always want a light on my Rivendell Custom All-Rounder. I'm a fan of getting up and going for a ride in the middle of the night when I cannot sleep. I do hope to someday figure out a front rack, but I have a few other projects brewing at the moment and lack resources. I suspect adding a small front rack and bag, the additional front end weight will change the handling again... Perhaps we will see. I had the same stability problem on my Quickbeam using a Nitto front rack, Shimano dynamo, and a Busch&Müller Lumotec IQ Fly with an even heavier Velocity Dyad rim. With rack and light, the bike had a similar stability issue. Without one or the other, everything was fine. I had changed the tires on the Quickbeam from the 700x35 Pasela TG tires to the much larger volume 700x42 Schwalbe Marathon Supremes and the shimmy problem went away?! I do not have the head for understanding the relationship between headtube angle, tire size, fork rake, geometric trail...etc. Whenever reading the discussions pertaining to the subject, in my mind it sounds more like listening to the teacher from the Peanuts cartoon. I read the words, hear the sounds, but it's all incomprehensible. I know they are all related, I just cannot say definitively which variable needs to be changed. Changing frame geometry on an existing bike isn't really an option, so the experience makes good conversations with a frame builder when ordering something new. It doesn't help me in understanding what variable to suggest changing to meet the original poster's desire. Bikes ARE FUN! Fun to think about, interesting to make changes with, like large dynamic rolling experiments or kinetic art. On Apr 26, 2:05 pm, SFcyclotourist <yoj...@gmail.com> wrote: > On Apr 26, 9:21 am, Ken Yokanovich <reflector.collec...@gmail.com> > wrote: > > > > > I had been riding my 60cm custom All-Rounder with 700x35 Pasela TG > > tires. Since more permanently mounting a Schmidt dynamo hub and > > light, something caused the front end handling to be a bit off. At > > 10-15 mph I'd get a "shimmy" or wobble, no handed was not an option. > > Where/how did you "more permanently" mount the head lamp? On a front > rack, perhaps? > > > I mounted some Jack Brown 700x33.3 tires and the handling issue was > > dramatically reduced. (Not entirely gone.) If I use a standard wheel > > the bike handles wonderfully. (Yes, the Schmidt wheel is true, > > dished, and tension balanced.) > > When you switch to a standard wheel, do you also leave that head lamp > in place? > > Your tire-changing experiences parallel mine. I had 700x35 (non TG) > Paselas on my bike, and riding no-handed at <20mph speeds wasn't an > option due to shimmy. Additionally, I'd get a speed wobble over about > 35mph. Switching to 700x32 Paselas (TG -- only because that's what > was available at my LBS) has drastically improved those problems (low > speed shimmy hugely reduced, high-speed wobble now gone). > > Jobst Brandt has written that heavy wheels/tires on a lightweight, > flexible frame may lead to increased risk of these types of problems. > I think wheel-weight is a significant factor. > > The issue with your Schmidt hub+wheel causing shimmy is, however, > _very_ perplexing! > > -Jim G --~--~---------~--~----~------------~-------~--~----~ 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-bunch@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 -~----------~----~----~----~------~----~------~--~---
