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Path: news.eternal-september.org!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 12:22:34 -0400 Organization: A noiseless patient Spider Lines: 201 Message-ID: <psd8fjppmrr12utvds6bm4i42ingn1bt8i@4ax.com> References: <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> <5fa8fjpqcnhi1e661moanf8bqtpc3jrlq6@4ax.com> <vd1bjk$3nokv$4@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Injection-Date: Wed, 25 Sep 2024 18:22:38 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5eb9c425b7ef9598cde8cc2b3d0094c3"; logging-data="3948043"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+ov28aj0TEFPTW51eeoQPvLzQjNn75BM0=" User-Agent: ForteAgent/8.00.32.1272 Cancel-Lock: sha1:LBAVfSrT/k9pC9JGdWTvJi+bJgw= On Wed, 25 Sep 2024 10:52:18 -0500, AMuzi <am@yellowjersey.org> wrote: >On 9/25/2024 10:20 AM, Catrike Ryder wrote: >> 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? >> ========== REMAINDER OF ARTICLE TRUNCATED ==========