Shifting gears....my theory

I have this theory I'd like to test out on other cyclists here.  I have noticed that when I join other cyclists at a light I am almost always the first to take off, and not by a little, either.  It's not that I'm a strong cyclist but that I downshift before stopping.  When I know I have to stop I automatically shift to one of my lowest gears so that when I start up again it will be easier for me.  That's the point of having gears after all.  When the light turns green others stand or do that slow wobble thing as they get up to speed.  I know fixies have to struggle but why don't geared bikes down shift before stopping?  

So my theory is that I'm used to driving a clutch and therefore may be more familiar/comfortable with the notion of shifting down.  If a cyclist is not used to driving an automatic transmission or doesn't drive at all then they may just leave it in the same gear all the time.  At least that's my observation on my daily commute.  

If you ride a geared bike then do yourself a favor and shift down before stopping.  It will make your ride so much more pleasant.  And it would be nice to have more company up in front.  :-)

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Permalink Reply by Lanterne Rouge on April 21, 2014 at 11:31am

I think the whole point of a bicycle with multiple gears is efficiency. I made the leap from SS/FG to multi-speed because at some point, I thought 'man, I would be so much more efficient and expend less energy if I had more gears." And so it went.

Permalink Reply by Madopal (16.5 mi) on April 22, 2014 at 3:19am

Jeff Schneider said:

It's just easier in terms of energy spent, and easier on the knees (possibly an important consideration for some middle aged people), if you make full use of those gears.  So I wonder sometimes why so many people don't.

+1 on this.  Also, just for kicks, I'd love to see a graph of age or amount of years having ridden vs. # of gears.  Talked to a number of ex-fixie guys who stopped riding fixie because accelerating & slowing down using the knees took its toll.
Finally, I can usually spot the newer cyclists.  Just count the cadence.  If they're not on a single speed/cruiser and they're tooling along at < 50 strokes/min...yeah.  Fun to watch them on Bike the Drive tackle the hill near Navy Pier.
Permalink Reply by Julia 3.5/7.5 mi on April 22, 2014 at 3:41am

I'm on both sides of this spectrum, depending on which bike I'm riding. In nicer weather, I have a 105 groupset on my cannondale synapse, and I can click through the gears like butter. On that bike, I always downshift at lights - so much so that it's second nature. On my other bike, an "all weather" miyata single speed, I'm woefully slow to start up - heavy bike + loaded for commuting + single speed generally puts me towards the back of the pack.

Though I'm not nearly old enough to complain about my knees (at 27!), I can definitely feel a difference after logging many more miles with the assistance of gears. I used to think I had trouble building endurance - turns out riding 30 mi on a single speed is just not my cup of tea. :)

Permalink Reply by Dave Jacque on April 22, 2014 at 3:48am

My lovely bride drives me crazy with the bicycle gears. She rides a motorcycle and drives a stick, but when she's on her 24-speed bicycle, it stays in 3rd gear. All. The. Time. When I ask, she says "It's fine this way." I think she just can't be bothered. 

Then of course, she complains because I keep getting so far ahead of her.

Permalink Reply by David P. on April 22, 2014 at 4:54am

Leaving the line in a lower gear ratio is certainly easier on the knees than doing so in a higher ratio, but for any given acceleration rate (to be a little more correct, let's say area under the curve) it will take the same amount of work to get to a given speed, regardless of whether you upshift across the whole cluster or mash off the line.

Permalink Reply by Mike Schwab on April 22, 2014 at 8:01am

The work that is done is the same.  But at a higher gear to start you have to exert higher force leading to higher stress levels.  If you exceed the human bodies limits, some tissue breaks downs.  It accumulates until it is so injured you have to stop.

Permalink Reply by David P. on April 22, 2014 at 10:47am

Jeff,

No need to sound condescending - I'm not sure you meant to, but it can come across that way. I suspect it would be quite a challenge to show a significant difference in work done over the first, say, 100 feet from a standing stop by a typical (not pro) cyclist. This is just an informed guess - I could be wrong. I took thermo and heat transfer and all that almost 20 years ago, and I've forgotten a lot.

Jeff Schneider said:

To get to a given kinetic energy (velocity), it takes the same work (energy) input to the bike, regardless of how quickly you do it (roughly speaking - ignoring rolling resistance, wind, etc.).  But your body is not a 100% efficient engine, so the energy you expend is actually work put into bike + waste heat.  You are more efficient pedaling at a reasonable cadence, making your energy expenditure lower than if you are mashing.

Your answer is from 1st semester calculus.  Mine is from 1st semester thermodynamics circa 1979, so my explanation may not be perfect either, but I think it's closer to the truth.


David P. said:

Leaving the line in a lower gear ratio is certainly easier on the knees than doing so in a higher ratio, but for any given acceleration rate (to be a little more correct, let's say area under the curve) it will take the same amount of work to get to a given speed, regardless of whether you upshift across the whole cluster or mash off the line.

Permalink Reply by Gecko on April 22, 2014 at 12:56pm

If we're having a physics discussion, we might be better served by talking about POWER.

POWER = WORK over a TIME period, so theoretically if you have gears and are racing someone else with one gear and similar power, you're using that power more efficiently to do the same amount of work in a shorter amount of time, i.e. accelerating to a given speed faster.

Back to the OP's original question though, I suspect it's a combination of laziness, inexperience, and apathy that causes so many people to disregard their gears.  I prefer to keep a fairly constant cadence so I'm always shifting up and down on my geared bike, but sometimes I find that I actually ride slower on the geared bike because I have the option to downshift when it gets hard (something my single speed commuter does not offer).

Permalink Reply by Marc-Paul Lee on April 22, 2014 at 2:56pm

I wasn't a very good physics student and it was waaaaay in the past for me but are we forgetting the mechanical advantage provided by the gears?  After all, I can lift a much heavier object than I normally could if I use a lever or pulley.  In a similar fashion I use the gearing of the bike to more easily initiate motion.  Am I missing something?  

Permalink Reply by Kevin Mulcky on April 22, 2014 at 4:10pm

Responding to the OP here and avoiding the physics lesson -

My theory is that most people who don't shift gears in their multi-geared bikes also don't adjust or maintain their drivetrain. They're probably keeping the bike in one gear all the time because it's the only one that works.

Permalink Reply by Crazy David 84 Furlongs on April 23, 2014 at 5:04am

A couple of comments.  I learned my multi-gear bicycling in a river town.   This means hills all of the time.    And so I quickly learned to shift shift shift.    And my next riding was, again, in rolling countryside.  So shifting became second nature.   Could I mash?   Probably, the gears made even that big hill up Wilson Avenue from Roslyn to Clarendon  doable.   

Then I came to Chicago.  And  I still shift.   It makes the bicycle safer to ride as acceleration is faster in the right gear, and most importantly, its not hard on the knees.  I am in the mid-50's and, knock on wood, do not have a trace of knee trouble.    And at least a part of this is that I ride in the right gear and do not put stress on the knees.    I suspect that the (rather arrogant) we don't need to shift comments come from people who were born after we last landed on the moon and have not yet wrecked their knees. 

As for Bike the Drive.   Wow.   What an arrogant characterization of BtD as something for only occasional bicyclists.  Some of us don't live on the lakefront and aren't forced to use the rather over crowded and dangerous LFT.   Bike the Drive gives us a chance to bicycle on the lakefront without dealing with the Greg LeMonde wannabes on the LFT.   And, of course, it also gives us a chance to take a few "ocasional cyclists" along to encourage them to ride more.   That's what I am dong...

Permalink Reply by Julie Aberman (Hochstadter) on April 23, 2014 at 5:19am

I shift down, it makes it just easier on my body to start up again after a light.  I can drive a manual car, but do it so infrequently and never got very comfortable with it. 

Same thing happens when I start shifting my chain ring. I get confused for awhile, then pick it up (like on Ragbrai where I have to do a lot of shifting due to the hills) and then forget it again after my ride. I  guess my brain can catch on, but there is a large learning curve in my brain every time. 

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