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Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Catrike Ryder <Soloman@old.bikers.org> Newsgroups: rec.bicycles.tech Subject: Re: Extensive article on Rivendell and Grant Petersen Date: Wed, 25 Sep 2024 11:20:46 -0400 Organization: A noiseless patient Spider Lines: 182 Message-ID: <5fa8fjpqcnhi1e661moanf8bqtpc3jrlq6@4ax.com> References: <vct3ic$2tr2a$1@dont-email.me> <sls4fj914qnt9is0crvsd4dpli978v8ebt@4ax.com> <vcukup$37v5r$5@dont-email.me> <jvl5fjt14puvrscsra3jrjj2lgr22qhhdq@4ax.com> <vcuvih$39ji0$4@dont-email.me> <oq26fjpl0hc62vq4jpe50htdoavd26mcgu@4ax.com> <vcvr4o$3hhf0$1@dont-email.me> <pnQIO.1160654$grz1.912786@fx03.ams4> <msl7fjljviv2kgo3p13hsffga55kjdpsfp@4ax.com> <Q0SIO.2217267$kpic.1696407@fx15.ams4> <hvv7fjt8cvlaq62uknoriusuvdmgr5a6i4@4ax.com> <fnVIO.806338$qP12.292583@fx02.ams4> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Injection-Date: Wed, 25 Sep 2024 17:20:48 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5eb9c425b7ef9598cde8cc2b3d0094c3"; logging-data="3924696"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18lpYNxNTmS3BjwXWVl/9GRqCzpddQpaUI=" User-Agent: ForteAgent/8.00.32.1272 Cancel-Lock: sha1:/Q0S1IURA4i5Ql1l26ql7akd7IQ= Bytes: 9857 On Wed, 25 Sep 2024 14:46:35 GMT, Roger Merriman <roger@sarlet.com> wrote: >Catrike Ryder <Soloman@old.bikers.org> wrote: >> On Wed, 25 Sep 2024 10:57:52 GMT, Roger Merriman <roger@sarlet.com> >> wrote: >> >>> Catrike Ryder <Soloman@old.bikers.org> wrote: >>>> On Wed, 25 Sep 2024 09:05:25 GMT, Roger Merriman <roger@sarlet.com> >>>> wrote: >>>> >>>>> Frank Krygowski <frkrygow@sbcglobal.net> wrote: >>>>>> On 9/24/2024 3:17 PM, Catrike Ryder wrote: >>>>>>> On Tue, 24 Sep 2024 14:14:41 -0400, Frank Krygowski >>>>>>> <frkrygow@sbcglobal.net> wrote: >>>>>>> >>>>>>>> You might do well to read some of the archives of this group. There have >>>>>>>> always been people posting opinions that were factually wrong, and there >>>>>>>> have always been people pointing out those mistakes. As I've noted >>>>>>>> earlier, having mistakes pointed out is a necessary part of the process >>>>>>>> of education. >>>>>>> >>>>>>> That's fine of the person being corrected understands that the >>>>>>> corrector is qualified to do so and is truly interested in making >>>>>>> things better. In my opinion, you fall far short of both those >>>>>>> standards. >>>>>> >>>>>> Your opinion on that matter is worthless. You don't have anywhere near >>>>>> the background needed to judge technical proficiency. Professional >>>>>> Engineering licensing boards of two different states have disagreed with >>>>>> you, not to mention those conferring my engineering degrees and those >>>>>> institutions for whom I've worked. >>>>>> >>>>>>>> There are many examples of ideas that were posted frequently, and noted >>>>>>>> as wrong. Most of them seldom pop up any more - and not only, I think, >>>>>>>> just because there are fewer posts. I think people actually learned things. >>>>>>>> >>>>>>>> Examples of mistaken claims? Chains wear by stretching the metal. Old >>>>>>>> frames get "soft." Increasing spoke tension makes a wheel more rigid. >>>>>>>> Tying and soldering spokes makes a wheel stronger. Headsets fail by true >>>>>>>> brinelling due to impact loads. Hanging a bike by the front wheel makes >>>>>>>> the spokes stretch... and many more. >>>>>>>> >>>>>>>> BTW, what was that stopping distance from 20 mph again? ;-) >>>>>>> >>>>>>> 20 MPH would be maybe 9/10 feet if I didn't concern myself with >>>>>>> slamming the chain rings into the ground or doing a face plant on the >>>>>>> ground in front of the bike. 30 MPH would be a little further. Two >>>>>>> front brakes work better than one, especially when the rider's weight >>>>>>> is already more over the front wheels before he applies the brakes. >>>>>> >>>>>> Right, good one. There is no way you can stop your tricycle in 10 feet >>>>>> from 20 miles per hour. That would require a deceleration of 43 ft/s^2 >>>>>> or 1.34 times the acceleration of gravity. IOW you'd need tires with a >>>>>> static coefficient of friction at least 1.34, plus absolutely perfect >>>>>> application of both brakes so that both wheels were at the absolute >>>>>> limit of traction but not skidding. And you'd have to be in a "nose >>>>>> wheelie" all the while, with your rear tire up in the air so every bit >>>>>> of your weight was on the front wheels. It's essentially impossible. >>>>>> >>>>>> For 9 feet, your acceleration would have to be nearly 48 ft/s^2, and >>>>>> besides absolutely perfect braking reflexes, you'd need tires with a >>>>>> static coefficient of friction at least 1.48. >>>>>> >>>>>> And 30 mph would be _much_ farther, not "a little." The velocity term >>>>>> gets squared in the relevant calculation, much as it does when >>>>>> calculating kinetic energy. >>>>>> >>>>>> I'm sure you don't know what a lot of that means. But what you're >>>>>> claiming is practically impossible. Feel free to prove me wrong by doing >>>>>> what you claim and posting video evidence. >>>>>> >>>>>> >>>>> Even if he means without thinking time >>>> >>>> Yes, I know I'm going to stop and my fingers are already on the brake >>>> levers. >>>> >>>>> 20mph is 6 meters or 20ft for a car, >>>>> which almost certainly can out brake the trike. >>>> >>>> I doubt that. >>>> >>>>> If a planned braking action on the MTB probably could reduce that a touch >>>>> as it has huge amounts of grip and braking force, and frame allows one to >>>>> get behind the rear wheel. >>>>> >>>>> Other bikes at best would equal, the old commute bike as it has weight to >>>>> the rear is surprisingly effective at emergency stops or just using the >>>>> rear brake hard, but even that will during a emergency start to lock the >>>>> rear. >>>>> >>>>> Neither of the road/gravel bikes would do well at emergency stops as your >>>>> in the wrong position ie far too forward. >>>>> >>>>> Roger Merriman >>>>> >>>> >>>> A few weeks ago, after posting about braking, I tested the Catrike's >>>> brakes at 15 MPH. I stopped at about 6 feet, keeping the chain rings >>>> off the ground. >>> >>> That?s really hard to see how, you?ve mentioned that the trike pitches >>> which suggests that its weight is quite forward. >> >> Indeed it does pitch forward. It's easy to lift the rear tire off the >> road, however, the center of gravity of me on the Catrike compared to >> someone on a two wheeler is much lower. LIfting the rear wheel of the >> ground still requires a lot of braking force. > >Lifting the rear wheel on the MTB in position ie off the rear wheel Is not >easy at all, if it’s more of emergency brake the rear wheel might lock if >I’m not in position in position your not lifting the rear wheel on flat >ground. > >Even my gravel bike tipping forward isn’t particularly an issue if I can >get in position and if not it’s more likely to lock the rear than lift it. > >My old commute bike with a lot of rear weight even on an emergency stop >your not going to lift it at worse it will lock. > >The weight being low isn’t the issue it’s the weight forward/rear and that >your weight is static. >> >>> Note that cable disks are by some margin less powerful than hydraulic >>> systems, ie even a fairly modest cheap twin pot is going to be many times >>> more powerful, let alone 4 pots and so on. >> >> I really don't understand the issue of more powerful brakes. I changed >> my Avid bb7s from long pull to short pull and I still have to back the >> calipers off so as to not lock up the brakes at high speeds. The >> brakes are perfectly capable of slamming the chain rings into the >> ground and pitching 205 lb me out on my face. I've heard of people who >> have had that experience. One on a Catrike 700 with an even lower >> center of gravity than my Expedition. > >That’s all to do with the CatTrike Geometry ie it’s weight forward so it’s >limited by its pitching, that doesn’t make the cable disks powerful just >that the geometry limits the trikes braking, I have had bikes with cable >disks a few different models in fact, powerful they are not, about the same >as rim brake bike. >> >>> I run Magic Mary?s at 2.40 they are soft and gummy tires and on tarmac they >>> are effectively glued to it! Even with that 6ft at 15MPH seems ambitious! >> >> I use road tires, of course. 40MM at 70/80 psi. I suspect my tires are >> glued to the road better than your knobby MTB tires. > >Not a chance, Marathons are designed for touring and commuting get many >thousands of miles out of those, compounded with higher pressures, my >Gravel bike with similar sized tires but half the pressure and more volume >and softer rubber and so on. Is likely to be a better at this. > >Let alone the MTB with soft sticky rubber much more volume 700*64 is a lot >of air a frame that allows one to get off the back its geometry etc, ie I >can if break to the limits of the tires for that reason. > >Your limited clearly by the trikes geometry, where as upright bikes >particularly slacker geometry MTB are able to utilise not just more >powerful brakes but brakes with absolutely enormous amounts of power, see >my posts few months back with the DH brakes. >> >>>> -- >>>> C'est bon >>>> Soloman >>>> >>> Roger Merriman >>> >> >> -- >> C'est bon >> Soloman >> >Roger Merriman > Do you really believe that a lower center of gravity does not make a bike more stable? -- C'est bon ========== REMAINDER OF ARTICLE TRUNCATED ==========