Bear in mind that what's nimble for a bird-boned climber will be different than what's nimble for me or you. You might want to track down the writings which Scott Cutshall did (Large Fella on a Bike - http://istanbultea.typepad.com/ ). He started riding at 500 pounds, and settled on a tandem-tubed Bob Brown bicycle which he rode for a significant time. He also interviewed a bunch of custom frame builders - some of whom may no longer be crafting frames.
With a lot of starting/stopping, smaller wheels will accelerate up to speed faster - a 20" wheel zips right up, for example. But, since that's outside of your range, I'd look at 26". A well-built wheel in that size works well and will feel "quicker" than a large volume 700C. I've never liked the term "nimble" for handling. "Predictable" is my bias, as the ability to negotiate sudden changes of direction and topography really does lie significantly in the hands of the person riding the bike. I've ridden mtb's which were like nervous horses - you had to work to keep them on track. That's fatiguing and not helpful in my book. Specific to Rivendell models, I'd try to take a look at a Sam Hillborne or an Atlantis for reference. I don't know what the bb position of that Trek 730 (which seems from your description to be the closest to what you want). but you may find the lower bb of Grant's designs give you better control. Bicycle handling are more than just trail and fork rake, to be sure, so I'd try to take into account what a fully realized design does. hope that helps, Jim / cyclofiend.com On Sunday, April 27, 2014 7:52:44 AM UTC-7, Chris Lampe 2 wrote: > > Not a huge amount of climbing, I live in Oklahoma. :) > > I'm 5' 11" and weigh just shy of 400 lbs so I definately tend toward > fatter tires. I'll be riding with MTB riser bars and although I've always > run a 3 x something drivetrain, I might change to a 2 x 9 or even a 1 x 9. > > > What I have now: > > Handsome Devil: 73/73 with a 45mm rake on the fork. Chainstays are set > up at about 43.5cm. 70mm BB drop. Basically an XO-1 upsized to 700c. > > 1983'ish Takara Highlaner. Similar geometry to an early 80's Stumpjumper. > At first I loved it for it's cushy and smooth ride but quickly found that > it's incredible length and a bad tendency to understeer make it unsuitable > for my everyday riding. > > 1995 Trek 820: Decent mid-90's MTB but high trail with a bit of wheel > flop. Still fun to ride and has relatively short chainstays. > > 1995 Trek 730: This is my project. It was originally a 700c bike and > I've put 26" wheels with BA's on it. I replaced the 40mm rake fork with a > 50mm rake fork and came up with a front-end geometry very similar to my > Devil. Trail about 60mm and little to no wheel flop. The chainstays are > 43cm. It's just an experiment right now but I really like the smaller > wheel size. I'm just about convinced that it will be worth it to take that > cheap aftermarket fork to a frame builder and have the canti-studs moved so > I can at least put a front brake on it and actually get out and ride. > > Ideally, all of this will inform a custom frameset in the future but > financial considerations may require me to modify an existing bike. > > On Sunday, April 27, 2014 7:42:40 AM UTC-5, Chris Lampe 2 wrote: >> >> I'm defining "sporty" and "nimble" as a bike that is designed to be >> ridden primarily on pavement, in a way that involves a lot of >> acceleration/deceleration, a lot of twists and turns in the road and a lot >> of sharp corners. The bike would rarely if ever be ridden for hours or >> tens of miles and most rides would be less than 10 miles. Maybe some MTB's >> fit this description. Maybe some city bikes qualify? I would be >> interested in hearing about actual bikes that meet this criteria as well as >> general design ideas. >> >> Some major points I'm curious about: >> >> Frame material: Steel, Aluminum, Carbon? >> Wheel size: limited to a choice between 26", 650B and 700c (because I >> want a bike like this and prefer to stick to the big 3). >> Tire width? >> Specific geometry features: short chainstays, long chainstays, high BB, >> low BB, etc..... >> >> >> I have some ideas about what would make a bike like I describe but my >> experience in riding different models is tiny. I know a lot of people here >> have a lot of experience riding different bikes plus the inclination to >> understand why those bikes ride the way they do. >> >> I look forward to hearing people's opinions. >> >> >> -- 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.
