I agree that closer to the axis of rotation should be better since it minimizes the moment of inertia. This suggests that less rotation of a front bag is better. In that case, here in the RBW world that there are bikes with high handlebars and tall headtubes such that it would be feasible (especially with moustache bars and horizontal brake levers) to attach a front bag directly to the headtube that never rotates.
On Wed, Feb 24, 2010 at 7:07 AM, Ken Freeman <kenfreeman...@gmail.com>wrote: > As I understand it, the best location for a front load isn't necessarily > lower, but primarily it should be closer to the steering axis. If you move > a bag lower, it gets closer to the steering axis. If you look at front > pannier racks, the center of the loaded pannier usually falls in line with > the steering axis. > > I think it also WANTS (not saying NEEDS) to be behind the front axle. This > leads to fork designs with low trail, which implies high rake, which is > essentially moving the front axle farther forward relative to the BB. While > some riders don't think it's essential to have low trail if you have a front > load, some randonneurs want to ride no-handed with a significant front load, > and access their stuff without affecting how the bike is running, especially > while they're riding tired. This is a different degree of stability than a > rider who in an errand run, moderate commute, or even a 25 mile regular > ride, is able to control the bike with both hands on most of the time. > > I don't know if any experienced randonneurs have done brevets with Rivs and > significant front loads, and are comfortable no-handed. I'd like to know, > because while I really like some Rivs and would like to try a Roadie or > something like a Ramb, I think I want a low-trail geometry. There's an > unbuilt 57 cm Bleriot on Ebay singing to me ... > > I tried an old-style handlebar bag on my Trek 610 with racier geometry (58 > mm trail after reducing the rake), with about 12# in the front bag. On a > hilly ride in northern Michigan, about 30 miles, I was able to ride well. > It did not feel as good no-handed or even one-handed as it does when > unloaded, and on a very slow section it was really hard to keep the fork > from flopping over. I have about and 8 cm stem on here. I don't think the > high-trail geometry is good for me, with a front load. > > On Tue, Feb 23, 2010 at 8:26 PM, Roy Yates <roydya...@gmail.com> wrote: > >> Doug and Rob, >> >> Thanks for answering my newb questions. I generally would imagine lower is >> better for a front bag, except its hard to see exactly why since a bag >> tightly fixed to the handlebars goes through the same rotation as a bag on a >> front rack as the bars are turned. I suppose it's related to the mysteries >> of bar/headset stability. >> >> In any event, I saw a custom rack this weekend, similar to a Nitto M-12 >> mini front rack with a classic looking boxy rando bag (although i can't >> remember which.) However, instead of a decaleur coming down from the >> bars/stem, the vertical U loop at the rear of the rack had an attached >> extension (2 vertical standards, with a cross bar) functioned as a decaleur. >> Frankly, it seemed like an excellent solution since it eliminates a bag >> attachment up near the handlebars, where it can get in the way, and perhaps >> compromise handling. I just wonder why I haven't seen this before? >> >> If you're not too tired of my questions, why are boxy rando bags mounted >> cross-wise on a front rack? Is it just because the horizontal way makes for >> a more useful clear map pocket on top or is handling also an issue? >> >> Thanks, >> ...Roy >> >> On Tue, Feb 23, 2010 at 4:30 PM, doug peterson <dougpn...@cox.net> wrote: >> >>> Roy: >>> >>> +1 for Rob's general comments about loading. It does boil down to >>> personal preference. We've had several lively discussions re: trail, >>> load placement, etc., with no clear consensus. But it keeps us >>> thinking. >>> >>> To your question, my answer is an un-qualified "Yes". I've tried an >>> old fashioned handlebar bag what mounts to the stem. This places the >>> top of the bag roughly at handlebar height. On my Atlantis, this set >>> up was unacceptably floppy & squirrely, and I'm not fussy about these >>> things. Acorn's Boxy Rando is roughly the same size and mounts on a >>> small Nitto (M-12?) front rack. The overall weight of the 2 bags with >>> mounting is roughly the same BUT the weight is a couple of inches >>> lower. Even with the Acorn stuffed full of food, jacket, etc., effect >>> on handling is minimal. The Acorn may sit closer to steerer tube as >>> well, now that I think about it. So yes, lower & further back is >>> better, in my experience. Note the Atlantis is a high trail bike so >>> YMMV. >>> >>> dougP >>> >>> On Feb 23, 11:42 am, rperks <perks....@gmail.com> wrote: >>> > in General handling should be improved by keeping the load/mass lower >>> > and above the axel. This largely falls into the personal preferance >>> > range though. The loads I carry in the front: >>> > Panasonic GF1 >>> > Spare Tube >>> > Wallet >>> > Phone >>> > Keys >>> > Extra water on a big day >>> > this keeps the load weight pretty low, all things relative. I tend to >>> > carry too much food, water tools, and god knows what if I am leaving >>> > for more than a couple of hours. I had my Carradice Nelson LF on the >>> > back for a while, and with both bags loaded the handnilg was >>> > acceptable, but in the back of my mind I knew I had too much stuff I >>> > would never use. I used to belive that suble position changes of the >>> > load could not change haanling in a noticable way, in this case it did >>> > though. >>> > >>> > Load position and amound can and has been be disussed for eons, what >>> > is optimum for you boils down to personal experience. Popular theory >>> > would have Grant's designs primarily as rear loaders, but baskets seam >>> > to work as well as smaller front loads. I have hauled 45lbs of teff >>> > flour home balanced on the handlebars of my crosscheck(high trail >>> > geometry) for a couple of miles, far from optimum but I survived, and >>> > it was way faster than walking. For me Optimum seems to be less than >>> > 8 lbs or so on the front of a high trail bike, with any additional >>> > load on the rear. I have not yet had a low trail bike to ride. Any >>> > time I put more than 30 lbs up high in the front the forks go wobbily >>> > before I have to worry about general handling. >>> > >>> > Rob >>> > >>> > On Feb 22, 5:03 pm, Roy Yates <roydya...@gmail.com> wrote: >>> > >>> > >>> > >>> > > It sounds like you're saying that for a front bag, lower is always >>> better? >>> > > Is that right? >>> > >>> > > Does that mean a not-too-tall bag that mounts just on a (mini?) >>> front rack >>> > > is better than the similar size bag that also uses a decaleur or just >>> uses a >>> > > handlebar mount? >>> > >>> > > Thanks, >>> > > ...Roy >>> > >>> > > - Show quoted text -- Hide quoted text - >>> > >>> > - Show quoted text - >>> >>> -- >>> 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<rbw-owners-bunch%2bunsubscr...@googlegroups.com> >>> . >>> For more options, visit this group at >>> http://groups.google.com/group/rbw-owners-bunch?hl=en. >>> >>> >> -- >> 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<rbw-owners-bunch%2bunsubscr...@googlegroups.com> >> . >> For more options, visit this group at >> http://groups.google.com/group/rbw-owners-bunch?hl=en. >> > > > > -- > Ken Freeman > Ann Arbor, MI USA > > -- > 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<rbw-owners-bunch%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/rbw-owners-bunch?hl=en. > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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