What drivel! What causes this massive weight shift from the front to the back of a car under acceleration??? This is a phenomenon known as load transfer and has nothing to do with a shift of weight. There might be a small weight transfer caused by small CoG displacement as a result of suspension pitch change, vertical suspension travel or tyre contact patch deformation, but that is all. How would this weight shift work in a solid suspension vehicle under acceleration? Or a vehicle witjh a massively long wheelbase?? Since this is a written medium, as you say, stop writing drivel and answer the question please. Quote some references, don't offer some pathetic, badly thought-out thought experiment. FYI the load shift phenomenon is exactly the same with a bicycle. Speed of acceleration simply goes to quantum of load shift but does not somehow negate load shift. When you sit on a pillion and the motorbike accelerates, the pillion rider experiences inertia, not weight shift!! When you are a stoker you are pulling on handlebars and pushing down on pedals - how on earth do you compare the two phenomena. Did you apply yourself at all to this answer, or are you simply unraveling your ignorance here and thinking everyone sucks up your nonsense? The torsion on a bicycle rear wheel will want to move the rear wheel forward, not the BB down. The resultant will be determined by pivot placement. On some designs this chain jacking will want to compress the shock. This causes bobbing. Our pedal action causes as much forward-backward motion as it does up-down. This causes bobbing. You say this robs power and you offer a quantitative equation to measure this. Please could you offer some substantiation of this, other than your speculative and questionable equation. Now please explain how in similar vein, on an unsuspended road bike, the deformation of a BB from side-to-side has never been shown or measured as a loss of power? You say all the energy of the shock compression is lost as heat and dissipated into the atmosphere, contributing to global warming? You evidently don't understand the concept of kinetic energy stored in the air spring of the suspension component, most of which is returned to the rider as the unit rebounds. Either this or you are being deliberately disingenuous. Either way, your responses are sheer nonsense. I'll have a go at this one... I will agree that the weight shift is due to the acceleration forces, not the shift of weight (although i think its just semantics)... With out acceleration the only force on the wheels is due to the weight (mass x gravity). so as the bicycle/car accelerates the acceleration force (or inertial force) acts backwards (mass x acceleration). The total force acting on the wheels is then a function of the resultant force (the combined force of the 2 accelerations) See diagram below: This is where I have to agree with JB becase of two reasons: 1) the acceleration of the bicycle is really really small. No matter how hardcore you think you are, its just not that much. So, yes, it is still there... and yes, it will cause weight shift.... but i would guess (not fact) that tilting yr head slightly back would have a simliar effect. Also remember, we not talking about track cycling acceleration, we talking about riding uphills. 2) The weight shift force is ONLY due to acceleration, which is the changing of speed. So if you are going at a constant speed, then that force dissapears completely. So in this context, most people say they lock it out while climbing, which is where theyexperience the bobbing, they will be at a constant speed. So considering all that, I would say weight shift due to acceleration plays very little role in when to lock out your shock
