Look, for someone asking for help you're really coming on pretty strong. Cut down on the preaching and maybe people will be more inclined to listen to your ideas.
So, someone designed a variable-volume hydraulic pump, good for him.
But despite going over the website I can't see how the variable stroke is achieved. I've seen the pics of the crank in the full stroke position and in the zero stroke position-but how is the transition achieved?
What is the degree of adjustability in the system - can it match the span of gearing that a MTB can offer?
Production costs - an ordinary drive train has quite few high precision components, apart from the bearings and freewheel/freehub clutch the rest can be pretty much stamped out from sheet metal. I suppose you'd need far more precision engineering in a hydraulic system.
Seals/ bearings/losses
On a bike seals for the rotating parts are fairly basic, which is OK since they only have to be splash proof. For a hydraulic design they would have to deal with both rotation AND pressure, which in all probability would make them drag more.
davebee: your design be to repair at home or would you need to take it to a dealer to protect the warranty?
M:Think Bigger, think Skiing.
dabac: ??? I don't get it, how would a bike compare to a set of skis? Are you saying it would be as maintenance-free as a set of skis? That comparison is way too lopsided to make any sense.
davebee: weight: How heavy would your design be?
M: How heavy are your skies......does it really matter?
dabac: Weight IS frequently important, first if you're riding in the hills, second it affects the feel and the handling of the bike.
This means there is a strong imperative to keep the size down(as a means of keeping the weight down) - but smaller size also means that the pressure will have to go up in order to achieve the same power transfer. For a car it doesn't matter much, but for a HPV you really want to keep the weight down.
davebee: Efficiency: Hydraulic systems tend to be rather inefficient due to the inherent nature of heat build up which causes energy losses in the system. How do you plan to mitigate this. Hydraulics also tend to be quite high pressure.
M: The winnig point !!!..... What Heat? Through what pressure?wir are not talking about tons of power here and everyone seems to ignore this fact.
dabac: You will get pressure, see above. And heat is not only a function of power transmitted, but also about the size of the power converters. It's all about power-to-weight ratio. Think brakes: the power dissipated during a descent by a drum/coaster brake is the same as the power dissipated by a rim brake for the same descent. Yet overheating the drum brake is quite easy while overheating a rim is quite rare. Discs are sort of intermediate, they are small, can run really hot, and cool off efficiently.
For a cyclist we're looking at maybe 300 W in sustained output, which isn't that much. But it has to be handled by gear weighing in at only a few pounds. And I'm far from certain that this is an easier task than what a car has to handle.
But if one were to use the chain stays as conduits it sure would be a step towards an ultra sleek bike...
