*to Hanlon's razor: Never attribute to malice that which is adequately explained by stupidity.
Κυνόσαργες

Sunday, 31 March 2013

Gear Inches, Weights

If you don't ride bikes enough to know what 'gear inches' are, which is likely to mean you have not yourself changed chainrings, cassettes, freewheels or cogs, skip this.  The rest... the few... I have thought much and am making some changes on my road bike and fixed gear.  Links, and more links.


It's all about efficiency.  I am a spinner, not a cranker.  I do not bother with a cadence monitor.  I know I am cranking too hard and spinning too slow if: my legs hurt early and my speed goes down a few km for doing more work.  And if you want to learn to spin smoothly, get a fixed gear: spin badly and get spanked.

On the commuting fixed-gear I had it at 74" (28mm tires, 44 ring, 16 cog), which worked well in Toronto, except for a few hills, and worked well when I stayed on the levée paths and east side of Tokyo.  Crossing the city, with its ridiculous number of lights to start off from, and finishing over an hour of that with some hills on the Yamanote side, I am wanting to take it down to 69.5" (28mm tires, 42 ring, 16 cog).  The latter is the way it came stock.  I rarely get spun-out now, and have brakes if I get spun out with the change.  It will be nicer on the hills and lights I cannot avoid.  11.5kg/25lb: not bad for a steel mid-range fixed-gear in a 59cm.  Too bad I have just found I need to overhaul the headset...  PITA.

On the road bike this is no issue on the flats: you can always find a gear, double or triple.  However, I want to climb the irohazaka this year, which means I need low gears, but I do not race in pelotons, which means I do not need the highs. 

I bought a triple, which was foolish: heavier, and a wider q-factor/tread, and I never use the big ring.  It came as 30/42/50, but I changed the 50 to a 46 and still rarely use it.  Fact is with an 11-28 cassette 42/11 is 102.2" and tall enough, outside of a paceline.  With the 50 the range is 28.7-128.6"; with the 46, -111.9".  Now a modern 'compact double' is still a range better for racing than nimble touring and training; a 34/50, even with my wide 11-28 cassette misses a lot of low end: 32.5-121.6".  What to do?

This is the shit!

The Sugino OX801D is devilishly simple: 'compact+'  The short version is that it is a double equal to a triple without the big ring, so instead of a q-factor of 165mm, 145mm, which is as narrow as a frame will let.  That much narrower is said to be 5-10% more efficient.  I have ordered the 44/30, with a 175mm crank (love to try 180mm, but the Japanese don't make that size...).  With the 11-28 cassette: 28.7-107" with a better spread of gears in the middle than a modern 'compact double'.  If that doesn't have enough wall-climbing ability I'll put a spare 26 ring on it: 24.8-107".  Incidentally, she's a steel frame/fork bike, 59cm, and still just 10kg/22lb.

Road bikes and fixed-gears come over-geared.  There are two reasons: built for doping racers in pelotons, and bravado.  Truth is, if you are cranking hard, you are not efficient: you are slower.  It's all about efficiency.  You want to go as fast as possible for the least work, money and discomfort.*  I have achieved that.

*least work - correct gearing to spin, not crank
  least money and discomfort - steel over plastic or aluminum; seat and handlebar bags over panniers and racks; tires neither too thin nor wide

11 comments:

  1. That LeMond looks retro fucking cool! I know shit about bikes but I'd steal that fucker in a moment back in the J.H. days.

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    1. You keep your hands off it! You can take me, but I can outride you.

      Fake-retro. Kind of got the wrong bike, but have been fixing it very slowly over the years: should have got this, if it had been available then: http://allcitycycles.com/bikes/mr_pink

      I like steel, but I also like modern components (integrated brake/shifters, 10speed cassettes...) so I am not a real 'reto-grouch', though see the merit of some of their ideas (shellacked-cotton tape, leather saddles, steel frames...).

      This is the most recent picture (notice the shit Japanese architecture!), but the asinine bell and frame bag are gone!: http://1.bp.blogspot.com/-g01x9-i_f_Y/UM2UIdZGTrI/AAAAAAAAAM0/uuTNCDOemFQ/s640/20121216182209.jpg

      Have to get a picture when the new crank is on, and she's 'loaded for bear'.

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    2. I checked the pic...glad the bell is gone. Who did that? Shoot them.

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    3. Ha. Guilty as charged. Idiots aimless all over the bike paths so needed one, but have one more discreet now. Usually doesn't work and have to yell, "OOOOOOOII!!"

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  2. "I am a spinner, not a cranker."

    I have no idea what this really means, so until you tell me otherwise I shall assume it is something filthy.

    And because the rest of those numbers mean nothing to me, I'll tell you a lifeguard story about efficiency. Every stroke you make while swimming provides propulsion but also creates drag, so ideally you want to take fewer, more powerful strokes. The pool I worked in was, randomly, 33m long. Swimming crawl I'd normally need about 20 strokes per length, while a former youth international on the staff needed low-teens.

    One regular client delighted us all by needing over fifty. His secret nickname was 'Bath Toy', for obvious reasons. It was always amusing watching new staff briefly panic when they first saw him in action, so similar was his swimming style to the desperate flailings of a drowning man.

    Still, he definitely got a workout from it, so maybe the joke was on us...

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    1. Added some links to definitions, above.

      Spin: faster rotation at a lower gear with less muscle effort is more efficient than...

      Crank: slower rotation at a higher gear with more muscle effort

      A few things as I understand them, and very different from swimming:
      - given an unchanged upper body position, drag is a constant (air-resistance and tire rolling-resistance) as the legs move but present the same surface area to the wind - not like swimming strokes
      - so is gravity, a constant
      - acceleration is energy expensive, whereas maintaining a pace is not (I can maintain a good pace for 100km, but don't ask me to climb a hill or hit a stoplight every 100m of that)

      Forget all that, and next time you go cycling use a cycling computer, or a smartphone app, and try a few gears around your comfort zone. You may be surprised where working harder makes you go slower.

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  3. That winding road ride looks brutal...

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  4. What's the elevation for the irohazaka?

    Sorry, I don't change things myself, although I would like to. The gear inches calculation thing is a little overwhelming, but I am rubbish at maths.

    I got my crank changed from the standard 53/39 to a 34/50 from memory. A smaller rear cassette would be ideal, but my setup is very old now and it was even a bit of a pain in the arse to do the compact crank. Anything over 5% I am grinding, so it would be nice to have one more gear to reduce the strain on the legs and knees.

    I am really just a complete newbie, I bought my bike second hand from a friend with a knee injury and it just turned out that it is a really awesome bike.

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    1. From Nikko station to Yumoto, well past the lake, I think it's about 1200m: which is almost as much as the worst pass on the 'Tour de France', the 'Croix de Fer'.

      I'm rubbish at math too: use an online gear calculator. http://sheldonbrown.com/gears/

      If you have a 34/50 the cheapest fix is not to change the cranks at several hundred dollars. Also, a smaller chainring is impossible: 34 is likely the smallest you can do, as it probably has a 110 bcd (spacing of the bolt circle). Cheapest bet is a new cassette at about $50 US. Get one with the biggest inner cog your derailleur will take, which is often 28, but sometimes 32. Check online or in a shop. A widely spaced cassette will sometimes leave you in a spot where one gear is too hard, but the next too easy. The best bet is what I did and have it widely spaced at the bottom, but narrow through the middle and top: 11/12/13/14/15/16/18/20/24/28.

      Good luck!

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    2. Thanks for the recommendation. I might have to look into it, I imagine changing the cassette wouldn't be too hard. I threw out the box for the derailleur, so I am a bit scared I may screw it up. The compact ended up being the heaviest Campo (2011 model I think) and the rest of my gear is Centaur. I had to change the derailleur as well for the compact.

      I had a look on Google maps, are you going to go around the mountain to the west? Based on that route, it was just under 24 kms for 1200 m gain. Not too treacherous. Any idea on the slope? The highest I have done is a 1600 m climb (Mt Tsurugi in Shikoku) which was over 35 kms. It took me about four hours, but it was quite a pleasant grade. I did another ride at the end of last year, this time it was a 700 m climb over 9 kms and it was HELL. Some parts were over 25% grade and I was doing about 4 km/h with the front coming up on down-pedal, but I didn't push. Tsurugi was just endless S-bends at about 5-10% for almost the whole way.

      When you thinking about going?

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    3. Hope to go autumn, before the snows.

      Are all the roads hellish in Shikoku? The stupidest grade I ever saw, and walked the bike up, was the road at the link, below. Short, but 150m over 1.4km is an 11% average, and parts were worse!

      http://goo.gl/maps/JgP9J

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