http://citycyclingedinburgh.info/bbpress/ CityCyclingEdinburgh Forum » Topic: Cycling goals for 2018 en Tue, 19 May 2026 17:51:07 +0000 http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=4#post-301146 Sun, 10 Feb 2019 21:45:45 +0000 Tulyar 301146@http://citycyclingedinburgh.info/bbpress/ <p>Gone very quiet, I suspect paper on this topic awaiting peer review. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=4#post-300834 Wed, 06 Feb 2019 10:14:06 +0000 I were right about that saddle 300834@http://citycyclingedinburgh.info/bbpress/ <p>@Frenchy</p> <p>Seconded.</p> <p>Though I'd have used the subjunctive mood: 'that @Arellcat henceforth write everything'. Can we get a ruling from the Writer? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=4#post-300832 Wed, 06 Feb 2019 10:07:49 +0000 Frenchy 300832@http://citycyclingedinburgh.info/bbpress/ <p>Good point.</p> <p>I withdraw my previous motion, and now move that @Arellcat henceforth writes everything. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=4#post-300827 Wed, 06 Feb 2019 09:32:34 +0000 I were right about that saddle 300827@http://citycyclingedinburgh.info/bbpress/ <p>@Frenchy</p> <p>Why stop there? That's poetry we're reading. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-300826 Wed, 06 Feb 2019 09:30:09 +0000 Frenchy 300826@http://citycyclingedinburgh.info/bbpress/ <p>I move that @Arellcat henceforth writes the Methods section of all scientific papers. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-300801 Tue, 05 Feb 2019 22:54:29 +0000 Arellcat 300801@http://citycyclingedinburgh.info/bbpress/ <p>In the midst of reading the history of the Soderberg number, I was amused to read upthread:</p> <p><em>P.S. I want to know how @Arellcat would do it.</em></p> <p>Having given it some consideration this evening I would take one good quality spoke from an Ordinary, nominally 12g and 0.7m long, and construct a single 0.5m long wire with a hook at each end. One hook is attached to the ceiling. The other hook is formed firstly to suspend the bicycle by either the saddle or top tube and the free end of the hook formed to provide a horizontal marker point that engages with the micrometer. Set the micrometer to a mid-scale value, say 10.000mm and ensure that the travelling end rests against the upper surface of the marker point. Then hang the bicycle (gently), adjust the micrometer until the marker point is reached, and take the difference in readings.</p> <p>Given typical values for Young's Modulus of 210 GPa and a bicycle weight of 15kg, the resulting elongation would be approximately 0.06mm, which is well within the discrimination of the micrometer. The pedant might advise to calibrate the spoke first, in order to determine Young's Modulus exactly.</p> <p>Then, for a bike of unknown weight, the tensile force applied to the spoke may thus be determined as the measured elongation multiplied by Young's Modulus multiplied by the cross-sectional area of the spoke, divided by the original length; and the weight of the bike is simply the force divided by g (9.81m/sec squared; or about 10). </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271435 Fri, 05 Jan 2018 13:55:32 +0000 I were right about that saddle 271435@http://citycyclingedinburgh.info/bbpress/ <p>@acsimpson</p> <p>I laughed out loud - thank you for that.</p> <p>As it happens...I did once carry a small bucket of mercury up two flights of stairs for professional reasons. Astonishingly heavy and, of course, ludicrously dangerous. I think you'd have to demolish the entire building if you couped a bucket of mercury down the stairs these days.</p> <p>I have witnessed an actual vat of quicksilver, but not in this country. One of the most sinister objects I've ever encountered. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271418 Fri, 05 Jan 2018 13:05:45 +0000 unhurt 271418@http://citycyclingedinburgh.info/bbpress/ <p><em>you're not entirely wrong</em></p> <p>I might ask for this as my epitaph.</p> <p>Vats of mercury, Nazi micrometers, squirrel recipes, Moroccan headgear... There's probably some sort of specialist business opportunity there. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271405 Fri, 05 Jan 2018 12:45:29 +0000 acsimpson 271405@http://citycyclingedinburgh.info/bbpress/ <p>unhurt, you're not entirely wrong. Provided an item is floating rather than sinking then the displaced liquid will be equal to the weight of the object (I think).</p> <p>So either you need to add some buoyancy of known weight to the bike or chose a different liquid. If I had to pick one forum member who would know where to source a vat of mercury I would probably start with IWRATS.</p> <p>A calibrated spring sounds rather too much like a measuring tool to be found in IWRATS shed. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271328 Thu, 04 Jan 2018 18:04:50 +0000 unhurt 271328@http://citycyclingedinburgh.info/bbpress/ <p>...</p> <p>Right. Yes. I may need more coffee. Or a replacement brain. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271326 Thu, 04 Jan 2018 17:50:48 +0000 I were right about that saddle 271326@http://citycyclingedinburgh.info/bbpress/ <p>@unhurt</p> <p>Nah, just pick the bike up. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271324 Thu, 04 Jan 2018 17:48:01 +0000 unhurt 271324@http://citycyclingedinburgh.info/bbpress/ <p><em>tyre deflection under zero load</em></p> <p>Would you not need to weigh the wheel first though? As the tyre is never under zero load when fitted? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271322 Thu, 04 Jan 2018 17:46:31 +0000 unhurt 271322@http://citycyclingedinburgh.info/bbpress/ <p>(re: volume: rats. Should have stuck with physics to CSYS...) </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271321 Thu, 04 Jan 2018 17:45:35 +0000 unhurt 271321@http://citycyclingedinburgh.info/bbpress/ <p>@Frenchy: I snorted.</p> <p><em>I am a committed experimentalist.</em></p> <p>And yet your eyesight hasn't suffered. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271320 Thu, 04 Jan 2018 17:38:12 +0000 I were right about that saddle 271320@http://citycyclingedinburgh.info/bbpress/ <p>What? Experiment with non-experimentalism? Head...<em>hurts</em>....feel...bad. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271318 Thu, 04 Jan 2018 17:17:04 +0000 Frenchy 271318@http://citycyclingedinburgh.info/bbpress/ <p><em>I am a committed experimentalist. It's cost me dear over the years, but so be it.</em></p> <p>Have you tried not being an experimentalist? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271317 Thu, 04 Jan 2018 17:09:19 +0000 I were right about that saddle 271317@http://citycyclingedinburgh.info/bbpress/ <p>@Frenchy</p> <p>I am a committed experimentalist. It's cost me dear over the years, but so be it. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271316 Thu, 04 Jan 2018 17:07:45 +0000 Frenchy 271316@http://citycyclingedinburgh.info/bbpress/ <p>Your method sounds both sensible and fun*, which is uncommon.</p> <p>I don't think you need to actually know the spring constant of the spring, you just need to calibrate it with a known weight (which I suppose is just a way of measuring the spring constant).</p> <p>*for an experimentalist, anyway. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271315 Thu, 04 Jan 2018 17:03:44 +0000 I were right about that saddle 271315@http://citycyclingedinburgh.info/bbpress/ <p>@Frenchy</p> <p>I have a model involving plotting tyre deflection under zero load, frame-only, frame plus one kilo, frame plus two kilos etc.</p> <p>Saves knowing the Hook constant of the weird composite spring? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271313 Thu, 04 Jan 2018 16:56:56 +0000 Frenchy 271313@http://citycyclingedinburgh.info/bbpress/ <p>@unhurt - that'd help you find the volume. To get the weight you'd need to know the average density of the bike. Which is probably most easily done by weighing it... </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271310 Thu, 04 Jan 2018 16:48:19 +0000 unhurt 271310@http://citycyclingedinburgh.info/bbpress/ <p>I was thinking submerge bike &amp; attachments in a tank of water of known dimensions and volume of water; measure displacement of water with micrometer; use figure to calculate mass of bike; calculate weight from mass. But all of the above suggestions are much more practical.</p> <p>P.S. I want to know how @Arellcat would do it. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271308 Thu, 04 Jan 2018 16:43:19 +0000 I were right about that saddle 271308@http://citycyclingedinburgh.info/bbpress/ <p><em>@iwrats - how do you weigh your bike using a micrometer?</em></p> <p>That's not a question I've previously given any thought to. Perhaps the tyres could constitute the 'stiff spring' in @Frenchy's model? </p> <p>Or I could take the bike apart into constituent substances of known density, melt these into cubes and calculate weight from the edge length? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271282 Thu, 04 Jan 2018 13:44:27 +0000 wingpig 271282@http://citycyclingedinburgh.info/bbpress/ <p>If you know the micrometer's precise mass and have a very long (but very uniformly dense per unit length) bit of wood and a very long tape measure, you could weigh a bike on a balance... </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271281 Thu, 04 Jan 2018 13:43:03 +0000 Frenchy 271281@http://citycyclingedinburgh.info/bbpress/ <p><em>how do you weigh your bike using a micrometer ? </em></p> <p>Hang it on a very stiff spring, measure the extension and apply Hooke's Law. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271278 Thu, 04 Jan 2018 13:16:24 +0000 dessert rat 271278@http://citycyclingedinburgh.info/bbpress/ <p>@iwrats - how do you weigh your bike using a micrometer ? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271277 Thu, 04 Jan 2018 13:14:54 +0000 I were right about that saddle 271277@http://citycyclingedinburgh.info/bbpress/ <p>@acsimpson</p> <p>I am duly banished.</p> <p>And you are correct in the torque wrench department, but it's not a measuring device in my eyes, more a safety device. Also I've stopped trusting it after a couple of messy incidents.</p> <p>Sprit level....nah. I set saddles by eye and feel. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271276 Thu, 04 Jan 2018 13:04:39 +0000 acsimpson 271276@http://citycyclingedinburgh.info/bbpress/ <p>@iwrats, Consider your self cast out (although as I'm not in charge this is optional).</p> <p>If you are fettling to the point where a micrometer is required then I would expect either a torque wrench or a spirit level to also be present. (depending on what the micrometer is for).*</p> <p>* In the name of full disclosure I should confess that I used a vernier gauge to assess disc wear last year but my torque wrench remained firmly in the box. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271262 Thu, 04 Jan 2018 12:03:01 +0000 Baldcyclist 271262@http://citycyclingedinburgh.info/bbpress/ <p>Not doing mileage targets, as they are just not do-able now with work, and home commitments, but I must do more than last years pitiful 860 (recorded) miles.</p> <p>1. get some fitness back.<br /> 2. when fitter (say starting March), cycle to / from work each way at least once a week.<br /> 3. ride more for pleasure - chasing commuting targets, and damaging bits of my body in the process probably sickened me of cycling.</p> <p>New child didn't help either, but he's 3 now, so time to start up again. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271258 Thu, 04 Jan 2018 11:58:33 +0000 fimm 271258@http://citycyclingedinburgh.info/bbpress/ <p>I made a <a href="http://citycyclingedinburgh.info/bbpress/topic.php?id=18494">new thread</a>. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=18455&page=3#post-271255 Thu, 04 Jan 2018 11:56:37 +0000 unhurt 271255@http://citycyclingedinburgh.info/bbpress/ <p>Only "trying"? That stings... </p>