Reducing Weight = Increase in Speed


In the world of cycling, there are physical principals which we must all adhere to.  In regards to weight it can be listed as follows:

  • The lower one’s center of mass to the ground, less energy will be required to go the same speed if one’s center of mass is higher.
  • The less weight one carries, the faster they will be.
  • Weight is preferred to be carried on the bike, and not on the body.
  • Weight on the bike is preferred to be non-rotating opposed to rotating (e.g. wheels, cranks).

All of this, of course, assumes aerodynamics is constant across all scenarios.  Which, we know is not always true.  Except for the lowering of one’s mass to the ground, which strictly applies to the amount of wind drag relative to ground level – and which deserves its own text book.

It’s no surprise that when one looks at the shapes of average Randonneurs, it wouldn’t hurt them to shave a little off of their waistline.  Myself included.  American population included as well.

It’s also no surprise that Randonneuring times tend to be slow.  Sure, we’re going far distances, but is that really an excuse to average 9 mph over a 1200k?  Granted sleep, eating, showering etc is all included in that time.  But at PBP 2011 I slept 12 hours and probably had 20 total hours off the bike (it is most likely less than 20), but that is still 11 mph moving average.  Less hours off the bike would only lower my moving average.

With that said, I still plan to finish PBP 2015 at about the same time, but I want to up my off the bike time.  Namely, I’d like to get a nice night’s sleep twice, at least 8 hours.  Add an hour before and after for some tinkering and that is 10 hours at each rest stop.  Another 10 hours at controls (which is roughly 40 mins/control) and we’re already at 30 hours off the bike.  Put 3 hours in the bank and that is an equivalent speed of 13.6 mph (775 mi/(90-33) = 13.6 mph).  That all seems totally easy, but as every randonneur knows, crap happens.  It is always much easier written (or said) than done.

The less weight one carries, the faster they will be
And I’m not talking about being a weight weenie, although some people may need to go there.  In 2011 me and the trusty steed were probably 275 lbs.  I accounted for 230 lbs of it, and the bike probably ticked in at 45 lbs or so.  No bueno…..

I rolled in with a Berthoud 28 (2 lbs empty) and a Carradice Pendle w/ Bagman QR (2.25 lbs empty).  I’m eliminating the Pendle.  Sure, I can put a gallon jug of water in the back, but it is way too much space.  It could fit the kitchen sink, and I took it.  The ultimate goal with the bike is to get it to 35 lbs.

My body weight….the everlasting project.  Currently, I sit between 225 and 230 lbs.  My body fat is about 25% according to my little scale thingy.  If I was to go to 10% body fat that would be 190-195 lbs.  Which I would love.  I have not seen that weight for 15 years.  And that assumes the above outputs from my scale are accurate and I would put on no more muscle mass.

I would like the combined weight – me, bike and bike stuff  – to be under 225 lbs.

Weight is preferred to be carried on the bike, not on the body
This usually puts the weight lower, which is physically faster.  Not only that, it is much easier to handle.  The biggest advantage is less strain on your body.  The three major contact points – feet, butt and hands – now have less weight on them.  Your core seems infinitesimally stronger.

If one was forced to choose between a pound off their body or a pound off their bike, they should always choose their body.  Obviously something is better than nothing.

Weight on the bike is preferred to be non-rotating
Rotating weight adds significantly to the amount of energy needed to continue to roll your bike along.  Depending on how you calculate the kinetic energy of a bicycle wheel, it is said that a pound on the wheel = 1.5 – 2.0 lbs on the bike.

This topic will be its own post in the future.

My focus is 1) reducing body weight, 2) reducing bike weight and 3) reducing rotating weight on the bike.  The hope is I can hold the 13.6 mph average needed to get me through PBP with ample sleep.


2 responses to “Reducing Weight = Increase in Speed

  1. Good luck in your PBP preparations! I am somewhat concerned about weight on the bike, but also want to make sure we have enough to deal w/ any unexpected weather or mechanicals that might arise. In 2011, we received quite a bit of rain on the 84-hour start so I was really glad to have had the appropriate gear w/ me. As for body weight, it’s always a work in progress for me.

    • That’s the trick, bringing exactly what you need – and nothing more. Surely some rain gear, a sweater, food and a small tool kit should all fit in a 10L bag.

      Body weight…..Sisyphus points and laughs at me.

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