Ta! On Fri, Dec 31, 2010 at 5:11 PM, James Warren <jimcwar...@earthlink.net> wrote: > > 42 > > > On Dec 31, 2010, at 8:56 AM, PATRICK MOORE wrote: > >> 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. >> > > -- > 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.
