CityCyclingEdinburgh was launched on the 27th of October 2009 as "an experiment".
IT’S TRUE!
CCE is 15years old!
Well done to ALL posters
It soon became useful and entertaining. There are regular posters, people who add useful info occasionally and plenty more who drop by to watch. That's fine. If you want to add news/comments it's easy to register and become a member.
RULES No personal insults. No swearing.
@amir
At the risk of being painted a contrarian I strongly believe that the only appropriate measuring tool for my cycling is a micrometer.
I look askance even at watches and invite Strava to take a walk on the sea bed.
There. I've done it. I'm an outcast.
I'd guestimate my personal one to be about 4-5 (based on infrequent trips to Edinburgh/Glasgow plus my fortnightly lift to writers' group). But the household one would be much lower as I'm effectively freeloading on the other half going shopping and picking things up for me (when he's going anyway) by car.
I try and minimise the miles in a car which are solely for me - i.e. motorised journeys which wouldn't otherwise have happened.
I probably manage fewer than one car-journey-just-for-me a year on average. Even with the odd trip to Ayr and Lincolnshire I comfortably cycle further than I drive/am driven over the course of a year. The children are subjected to lots of short car journeys when I'm unable to prevent them so the household's numbers will be disappointing.
can trying to get every thread on CCE to either go OT or descend into farce be classed as a cycling goal ?
Only "trying"? That stings...
I made a new thread.
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.
1. get some fitness back.
2. when fitter (say starting March), cycle to / from work each way at least once a week.
3. ride more for pleasure - chasing commuting targets, and damaging bits of my body in the process probably sickened me of cycling.
New child didn't help either, but he's 3 now, so time to start up again.
@iwrats, Consider your self cast out (although as I'm not in charge this is optional).
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).*
* 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.
@acsimpson
I am duly banished.
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.
Sprit level....nah. I set saddles by eye and feel.
@iwrats - how do you weigh your bike using a micrometer ?
how do you weigh your bike using a micrometer ?
Hang it on a very stiff spring, measure the extension and apply Hooke's Law.
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...
@iwrats - how do you weigh your bike using a micrometer?
That's not a question I've previously given any thought to. Perhaps the tyres could constitute the 'stiff spring' in @Frenchy's model?
Or I could take the bike apart into constituent substances of known density, melt these into cubes and calculate weight from the edge length?
I was thinking submerge bike & 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.S. I want to know how @Arellcat would do it.
@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...
@Frenchy
I have a model involving plotting tyre deflection under zero load, frame-only, frame plus one kilo, frame plus two kilos etc.
Saves knowing the Hook constant of the weird composite spring?
Your method sounds both sensible and fun*, which is uncommon.
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).
*for an experimentalist, anyway.
@Frenchy
I am a committed experimentalist. It's cost me dear over the years, but so be it.
I am a committed experimentalist. It's cost me dear over the years, but so be it.
Have you tried not being an experimentalist?
What? Experiment with non-experimentalism? Head...hurts....feel...bad.
@Frenchy: I snorted.
I am a committed experimentalist.
And yet your eyesight hasn't suffered.
(re: volume: rats. Should have stuck with physics to CSYS...)
tyre deflection under zero load
Would you not need to weigh the wheel first though? As the tyre is never under zero load when fitted?
@unhurt
Nah, just pick the bike up.
...
Right. Yes. I may need more coffee. Or a replacement brain.
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).
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.
A calibrated spring sounds rather too much like a measuring tool to be found in IWRATS shed.
you're not entirely wrong
I might ask for this as my epitaph.
Vats of mercury, Nazi micrometers, squirrel recipes, Moroccan headgear... There's probably some sort of specialist business opportunity there.
@acsimpson
I laughed out loud - thank you for that.
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.
I have witnessed an actual vat of quicksilver, but not in this country. One of the most sinister objects I've ever encountered.
In the midst of reading the history of the Soderberg number, I was amused to read upthread:
P.S. I want to know how @Arellcat would do it.
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.
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.
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).
I move that @Arellcat henceforth writes the Methods section of all scientific papers.
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