31? 41? Where is coffee .... What number am I thinking of?
On Fri, Dec 31, 2010 at 9:49 AM, doug peterson <dougpn...@cox.net> wrote: > Got it; many thanks. > > Patrick, RR31 is 7 years old. We're up in the 40s now. > > dougP > > On Dec 31, 8:25 am, David Faller <dfal...@charter.net> wrote: >> Drink a little more coffee, Patrick... >> >> On 12/31/2010 8:15 AM, PATRICK MOORE wrote: >> >> >> >> > So RR 31 is out -- great, must buy it. Good article. Whatever G's take >> > on trail, he's built me three excellently handling bikes. >> >> > On Thu, Dec 30, 2010 at 9:50 PM, Bill Gibson<bill.bgib...@gmail.com> >> > wrote: >> >> Did you know the pdf author was Milhouse Vanhouten? Cali is a mythical >> >> place, you know...I have it, but I bought the pdfs from Rivendell...I >> >> hesitate to violate copyright , but I will quote, assuming you are a loyal >> >> customer..."Experiments With Rake& Trail" >> >> Fork rake is how much the front wheel is offset from >> >> the steering axis a straight line through the center of >> >> the head tube. The aspect of the bike s steering geometry >> >> that s affected by fork rake is called trail. Don t confuse >> >> it with a trail you ride on. >> >> Road bikes typically have between 2-inches (50.6mm) >> >> and 2 1/2-inches (63.5mm) of trail, and bike journalists >> >> who ve written about trail have said 2 1/4-inches >> >> (57/58mm) of trail makes a bike not too quick, not too >> >> slow, just right. >> >> Trail theory says that more trail makes a bike easier to >> >> control at high speeds and over rough ground. >> >> Mountain bikes typically have between 2 3/4-inches >> >> (69.8mm) and three inches 76.2mm) of trail. >> >> Less trail, according to theory, makes a bike easier to >> >> control at slow speeds, but harder to control when >> >> you re going fast, hitting bumps, or both. >> >> Trail is affected by: (1) the wheel radius; (2) the head >> >> tube angle; and (3) the fork rake (offset).There are three >> >> ways to increase trail: >> >> Bigger front wheel. >> >> Shallower head tube angle. >> >> Less fork rake. Most folks who start thinking about >> >> trail temporarily get confused at least three times, and >> >> think more rake makes more trail. Nupe. >> >> To calculate trail using arithmetic: >> >> Trail = Wheel radius/Tan. of head tube angle minus >> >> fork offset/Sin. of head tube angle. >> >> If that s Greek to you, we should be in the same club. I >> >> have it programmed on my computer here, so I just >> >> plug in the numbers and there you go >> >> >> How Trail Affects Our Frame Designs >> >> When I design a Rivendell, I find the typical tire the rider >> >> will ride, and then the biggest. For all-purpose road riding, >> >> I shoot for 60-61mm of trail with the most common >> >> tire. That s more than what experts have said results in >> >> neutral handling, but they are not the boss of me. Nor >> >> should they be of you! >> >> Then I see what the trail is with the largest tire. Normally >> >> a customer will say, I ll ride a 700x28 most of the time, >> >> but there are some fire roads here, >> >> and I ll ride 700x35s when I go >> >> there. Well, that works out just >> >> fine, because the bigger tire will >> >> increase the trail, making the bike >> >> better for the fire road (so goes trail >> >> theory). >> >> Most frame designers have a trail >> >> figure they re comfortable with, >> >> depending on the bike s intended >> >> purpose. But some copy other manufacturer s >> >> geometries not a bad >> >> thing to do, and I hope we haven t >> >> reached the point where somebody >> >> out there considers Xmm of trail to >> >> be intellectual property. Finally, >> >> some builders just know from experience >> >> what works, and don t think about trail. That s >> >> fine, too! >> >> In Italy in the 80s it was common for the top makers to >> >> put 45mm of rake on each fork, regardless of the >> >> frame s head tube angle. The big bikes, which almost >> >> always had steeper head tubes, didn t have much trail, >> >> but the little bikes (with slacker head tubes) had more >> >> than plenty. I wouldn t say that s all that fine; in fact it >> >> seems odd to me. But these same Italian frames were >> >> ridden to many prestigious victories, which will impress >> >> those in the results speak for themselves camp. I m in >> >> the trail doesn t win races camp. >> >> When you first learn about trail, you may find yourself >> >> getting obsessed. It happened to me and I ve seen it happen >> >> to others. Trail is interesting, but it is not the sole >> >> splainer of bike handling, something nobody knows better >> >> than Waterford s Marc Muller (more on him later). >> >> The Educational-Type Fun Begins >> >> FOR ABOUT SEVEN YEARS I VE WANTED to experiment with trail >> >> by getting some forks with adjustable rakes, so we did. >> >> We also got non-adjustable forks with no rake, and with >> >> 65mm (whopping lot) of rake. You can do that when you >> >> have your own bike company and a publication to get >> >> out, but it takes more than snapping your fingers. >> >> The bikes are 59cm Romuluses. The Romulus is a road >> >> bike with what I think is a perfect geometry for allaround >> >> road riding. Pertinent to this story, it has a 73- >> >> degree head tube with 42.5mm of rake, which, with the >> >> stock Ruffy-Tuffy tire (343mm radius), results in 60mm >> >> of trail. It is as familiar to me as it gets. >> >> We equipped three bikes with different forks adjustable >> >> rake, 0mm rake, and 65mm rake; and of course we have >> >> a normal one, too (42.5mm rake), so really, four. I rode >> >> it up and down Mount Diablo and the local streets and >> >> roads. I rode it loaded and unloaded, on smooth and >> >> rough ground, holding onto the >> >> bars like you re supposed to, and >> >> no hands; over speed bumps (with >> >> hands and no hands), with a heavy >> >> basket, and at different speeds. >> >> The Problem With This Test >> >> It combines objective numbers and >> >> subjective feelings, and what I feel >> >> may not be what you d feel, because >> >> maybe we re used to different >> >> bikes, or one of us is more sensitive >> >> than the other. Also keep in mind >> >> that describing bicycle handling >> >> with normal language isn t always >> >> satisfactory. What I call quick >> >> might not feel so quick to somebody >> >> who s used to a 1987 64cm Ciocc (rhymes with >> >> poach ) Italian racing bike, for instance. >> >> Then this: I headed into this test knowing it would make >> >> a Reader story, and I found myself looking harder for >> >> things that I might not notice normally. I went out hoping >> >> to find hugely noticeable differences, and any >> >> nuance of the bike that suggested that got pounced on >> >> promptly and may be overplayed. I m not saying I couldn t >> >> tell a difference, I m just saying there s a natural tendency >> >> to overstate the differences for the sake of a good >> >> story, even when I m aware of that phenomenon. >> >> But After All That, Here s What I Think >> >> I could get used to any bike here. Off the bat I d say I d >> >> have a harder time getting used to a bike with too much >> >> trail than I would to a bike with too little, but bikes are >> >> fun to ride no matter what, so I d get over it. >> >> Also, I suspect the differences in the extreme versions >> >> tend to get neutralized when you re on the bike manhandling >> >> it. I think this because the biggest difference >> >> came out in no-hands riding the low-trail bikes were >> >> easy to ride at slow speed, where the tons-o -trail bikes >> >> were hard; and at high speeds it was just the opposite. >> >> But at slow or high speed, as long as I had my hands on >> >> the bars, it didn t seem difficult either way. >> >> As a bike designer, I find that quite comforting, but I still >> >> work hard to thread the needle. (Go to the next page now.)... >> >> >> There's lot's more and pictures that explain a lot, so if Grant& co. give >> >> permission, or if we can do this in secret with nobody seeing... >> >> or buy Part No. 24-127, RR 26-35! >> >> >> On Thu, Dec 30, 2010 at 9:21 PM, doug peterson<dougpn...@cox.net> wrote: >> >>> Does anyone have this as a PDF? Specifically looking Grant's article >> >>> on the eternal trail question. The Atlantis& I have been out messing >> >>> with loading again....the things you start mulling about during >> >>> winter... >> >> >>> dougP >> >> >>> -- >> >>> 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. >> >>> For more options, visit this group at >> >>>http://groups.google.com/group/rbw-owners-bunch?hl=en. >> >> >> -- >> >> Bill Gibson >> >> Tempe, Arizona, 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. >> >> For more options, visit this group at >> >>http://groups.google.com/group/rbw-owners-bunch?hl=en.- 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. > For more options, visit this group at > http://groups.google.com/group/rbw-owners-bunch?hl=en. > > -- Patrick Moore Albuquerque, NM For professional resumes, contact Patrick Moore, ACRW at resumespecialt...@gmail.com -- 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. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
