Does the distribution of total weight between a bicycle and its rider matter?

[FlyingTank]

Assuming the total weight of a bike and its rider are constant, does the distribution of the weight between the bike and the rider make a difference? From a physics standpoint, does it matter whether I weigh 203 lbs with a 20 lb bike or if I weigh 200 lbs with a 17 lb bike?Although I cannot explain why, I perceive that the distribution makes a difference. For example, I have the perception that riding my bike with a 10 pound backpack is easier than riding with 10 extra pounds on my bike frame (i.e., panniers)

[RideUrban]

The proportions between rider weight and bike weight don't matter so much.....what you're noticing is the distribution of rider (and backpack) weight that is making the difference. Weight distribution has a lot to do with how a bike feels....and thus, how almost every bike frame is designed. Frame makers can design the geometry to give all kinds of different riding characteristics.....better cornering, stability in steering or downhill riding, touring with loaded panniers, dirt jumping, freestyle tricks, etc. When you ride with 10 extra pounds on your back, you're shifting the weight distribution slightly backwards, but not enough to grossly affect the design of the bike. When you put that weight over one of the wheels, however, EVERYTHING changes. This is also why setting up your cockpit (seatpost, saddle position, stem length/height, different bars, etc) can have so much to do with how a bike handles and feels. When people make frankenbikes they often end up with something that doesn't feel right or is uncomfortable to ride. Hope this helps some.....it's a pretty complex subject, but the bottom line is really to try and match frame design to the intended purpose, knowing that weight distribution is probably the #1 consideration. )

[mirageguitarworks]

Actually, riding with a backpack raises your center of gravity which provides a perception of better stability and performance while just the opposite is true.Having the load as close to the ground as possible is far better for bike and rider.

[DH1]

Yes it matters. The lower the center of gravity is to the ground, the more stable the bike will be. However the closer the weight is to you (on your back or in your body) the more "feel" you will have and thus control over it.People will dispute the logic but lighter bikes are more maneuverable and easier to climb with. Add the weight to your bike and the bike will feel more solid (stable), but it will handle more sluggishly. Other things come into play like steering geometry.Another thing that adds or detracts from stability is wheels/tires. The rotating mass acts as a gyroscope (just like the one you played with as a kid). The faster and heavier the spinning mass, the more stable it will be. Smaller and lighter will be easier to flick around....so heavy tires and wheels = stability, lighter tires and wheels= maneuverability and feel.

[bleedinggumsburns]

Never ride with a backpack ! That's dangerous, Ideally 1/3 of of your body weight should be on the saddle, 1/3 on the handle bars, and 1/3 on the pedals. Also get yourself a good helmet, a pair of gloves, and a rear view mirror, they just might save your life !

[GlennB0490]

The only real advantage of carrying weight on your back, would be when you are travelling over irregular surfaces out of the saddle. Even then the advantage is tiny.This is going to be a bit difficult to explain, but I will give it a try.Let's say you are strapped into a rigid frame and run over a brick on the road. The entire weight of you and the bike will need to be raised the height of the brick. There is a lot of energy to be absorbed. If you go fast enough, you will probably wind up with a snake bite puncture and a flat spot (or cracks) in the rims.If you imagine repeating the exercise with a (long travel) full suspension mountain bike. The energy needed to get over the brick is significantly reduced. The weight of the wheels and the fixed section of the forks accounts for most of the energy. The rider and the bikes frame move very little. In your case your legs and arms act in a similar manner as the suspension on the mountain bike. So the difference in performance would be the difference between sprung and unsprung weight.There may be another advantage if the extra weight can be used to aid pedaling at low cadences.------------Now if your back pack gives you a better aerodynamic shape that is another story entirely. You can get HUGE advantages from aerodynamic improvements.