The Lounge of Terrestrial Wheelmen

[FaultyMario]

There are videos on YouTube about how disengage a clipless pedal. There's a British channel that's very good.

Basically, in a loose gear and with your inner foot (right for LHD countries).

[Tom Servo]

My wife and I have both managed to avoid the clipless "fainting goat" fall. I just posted up next to the wall of my house and got used to clipping each foot in and out over and over again. Probably spent about 10 minutes just doing that while holding myself steady with my arm against the wall. Then rode around in a quiet area leaving one foot disengaged and just clipping in and out with the other for another 20 minutes or so before I started clipping in with both feet, continuing to practice getting in and out.

The nice thing about SPDs is that they're designed to let your foot go if you yank on it hard enough. My Speedplay pedals won't let go no matter how hard I pull, so if I forget to twist my foot in an emergency, ain't no way I'm not hitting the ground.

[Cam]

That's exactly the reason I don't like Speedplay pedals. They are absolutely locked in, which is not what I want in the event of a crash. My Look Deltas (roadie) and Crank Bros. Egg Beaters (mtb) will pop out if pulled hard enough.

[Blerpa]

Well, one can still run flats if anything else is inconvenient

[G'day Mate]

I've yanked hard enough to pull my foot out under acceleration. Before I knew it I was sitting on the top tube with one foot skating along the road. I do not recommend this.

[Tom Servo]

Yeah, I like them that locked in. It's reassuring to know my foot is staying locked to that pedal when I'm really trying to accelerate as hard as I can. It's also saved me a few times in the wet.

[G'day Mate]

I adjusted them to maximum tightness soon afterwards

[Blerpa]

So, i did few km today to pay visit to my mother... one thing I noticed was I did find myself often seating naturally on the lower back of the saddle... just inching out with my butt from the normal seating position.
I suppose I should try pulling the saddle more backward, right?

[SportWagon]

Actually I thought the pedals were going faaaaairly slowly for a "spun out" descent.

Good point about the shoe braking though

Clearly he pulled out before getting spun out.

But your observation got me curious, and I dug up my old Gran Turismo oriented gear ratio speed calculator and have made a temporary copy at http://backup.toxs.net/~gtxftemp/gt/gears/

The calculator is oriented towards Gran Turismo which expresses ratios as a product of two reductions, but I decided to abuse my own facility for a not-quite-intended purpose, and therefore emulate a 48 tooth chainring by using the inverse 1/48 or .0208333333...

Another interesting observation is that the RPM number 5280 * 12 / 60 / 3.14159265 = 336.135 causes the calculated miles-per-hour value to represent the traditional English Front/Rear*27 "gear number". (You turn mile-per-hour into inches per minute, basically, and then divide out the pi too).

Anyway here's a sample chart of speeds in mph for RPM assuming an actual 27" wheel, a 48 tooth chainwheel and the indicated cogs.

http://backup.toxs.net/~gtxftemp/gt/...&mph=&reorder=

Here's isolating the two often used for track and road; a rear cog of 14 or 18, respectively.

http://backup.toxs.net/~gtxftemp/gt/...&mph=&reorder=

The calculated number in the table is speed in mph, and the 336RPM entry is given to tell you the traditional English gear size.

In fact, the calculated speeds are a little high (actually changing 27 to 26 might give a more accurate actual estimate). But we can see that, where the track cyclist might conceivably manage 45mph, the corresponding road cyclist would be able to well over 30mph. Expert cyclists can spin at at least 140RPM, or slightly more, for at least short bursts. If you think the road cyclist used a different gear, you can pick it from the first chart.

The cyclists in the picture didn't really seem to be going extremely (Alpine descent) fast.

Sometime I should rework my facility to produce an explicit cycling-oriented one.

I'm not sure how long I will leave the above URLs working. If Random wanted to host the (Gran Turismo themed, after all) CGI here, I'd be willing to help him try. (Or hey, anyone could run the CGI on their Android phone if they run Apache 2 under GNURoot Debian).

You know, the difference between assuming 27 inches or 26 inches for the wheel is actually quite substantial... (Approaching 4 percent, after all, duh!)

http://backup.toxs.net/~gtxftemp/gt/...=&reorder=tire

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Of course, it might be intuitively obvious to even the most casual observer that the two key numbers are 18 and 14; demonstrated/recalled by me as the cogs used for road and track. So if a skilled track cyclist can obtain a certain speed, a similary skilled road cyclist should be able to attain 14/18 or 7/9 of that.

That is, simply, if the track cyclist can manage 45mph (briefly), the road cyclist should be able to manage (e.g. downhill) 7/9*45 = 35mph, and perhaps even more since they will not be reaching power limits. Possibly more or less depending on the actual cog (and chainwheel) they use (and their skill).

[Tom Servo]

Not sure what the CGI is written in (perl?), but it might be a fun exercise for me to convert it to something that'll run natively on Windows/Mac/Android (probably not iOS since I think you have to have a non-free developer license for that) if you feel like sharing the source code. No promises, but I've been meaning to poke around in some .Net lately, or might even be able to redo it in Javascript with React/React Native.