Weight and Reaction

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Weight

In physics,

weight (F) = mass (m) x gravitational acceleration (a)

expressed in unit kgm/s²

 

where,

(F) is in Newton

(m) is in kg, this is what we usually we refer to as layman's 'weight'

(a) is 9.81 m/s², a constant

 

As my physics teacher cautioned, do not attempt to bring this terminology to the wet market when you're buying fish, meat, etc.

 

For ease of discussion, I'll use the terms

'weight' when I actually mean to say 'mass', and

'force' when I actually mean to say 'weight'.

 

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I often heard the notion that you don't have to spend your $ on lightweight parts for your bike, but instead just lose your body weight, or pack your hydration bag light. Basically, to make lower the rider's weight and/or anything clinging on the rider.

 

Reaction

In physics, this would only mean that the total weight that reacts on the ground (bike + rider + paraphernalia) is lighter than it would.

 

However, in the case of rider cranking the bike, that's a different scenario. The force needed to be exerted to the pedal is still high, due to the bike's weight.

 

So, if you empty your hydration bag, or lose your body weight, the reaction force is only reduced to the saddle (most of it), pedals and handlebars - the points where the rider + paraphernalia are supported. You still have a heavy bike to crank uphill, to push uphill during those steep (and/or long) climbs, or to carry on your shoulders (should you need to) during hike-a-bike.

 

While it might be nice to pack light, and a good thing if you're losing weight, those do not have anything to do with reducing your effort on a heavy bike, especially while riding uphill.

 

However, do not be discouraged to lose weight by riding a bicycle. You'll enjoy better health, toned body (especially sexier butt) and probably would gain more muscle mass. Or is it muscle weight? Whatever.