77Univega

- - Anybody have experience with the Liquid Drive or Hydra-Drive bicycle?

https://www.powerengine.com/aitx006hydbiksum.htm

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DieselDan

Someone adapted a hydrastatic transmission on a bicycle. Kubota has used those for almost 20 years in lawn tractors.

steveknight

I saw the prototype bike on ebay to help rasie money for more research.

phidauex

Its a neat idea. True continuous variable transmissions are something bikes could benefit a lot from, and fluid drives can be very high efficiency. It'll be interesting to see where this goes.

peace,
sam

Rev.Chuck

I used to work on hydrostats. It is hard to believe they could make a reliable rotary pump with swash plate for less than a grand. The losses would be greater than a chain or even gear/shaft drive. It would be pretty tidy tho. With a little computer you could even make it stay in your ideal cadence regardless of ground speed. Seems like a cvt would be cheaper and easier to do, with less power loss.

shoerhino

Aaaahhh .. The Red October.

I was behind one once. We went around a corner and he was gone....

Ok, so that was corny but the whole idea seems like someone solving a problem that doesn't exist.

bostontrevor

Yup. See also, shaft drive.

phidauex

When chain'ed bikes were invented people said the same thing, that it was trying to solve a problem that didn't exist. Same thing when the derailluer was invented.

I agree that it is important to not fix things that aren't broken, but it is also important to know the limitations of your current mindset, and recognize how a new design could fit in. Like that guy in 1899 at the patent office who claimed that everything that could be invented had already been invented. Eventually something will replace the chain drive and derailluer, and thats a fact. I don't know if it is this technology, but it'll be something, for sure.

peace,
sam

catatonic

I'd love the idea...it removes a few hundred parts on the bike

ivan_yulaev

No thanks, at least, not yet. Messy fluids, leaking seals, not my idea of a good day.

Dirtbike

Arent KTM's 450s now coming with 2wd via hydrastatic drive?

I imagine that the system would be kinda squishy unless solid lines are used.

juicemouse

Despite what the proponents of the system tell you, a ballpark average for the efficiency of energy transfer of a hydraulic pump is about 40%. Chain drive, even with a derailleur and a really dirty system, has a ballpark average of more like 90-95%, and even better with a little routine maintainance. This is without even comparing the weight and reliability of both systems. Sorry to be a downer, but unless someone's invented the "miracle pump", it seems as though this type of system is *not* solving a problem that doesn't exist.

ignorant

We have a winner... I used to build cars @ college for the SAE's Mini Baja races, most cars used a CVT off of a snowmobile or go kart. I have seen Hydrostatic mini baja cars work, not very pretty. Slow Slow Slow... It's a really neat idea except for the fact that most pumps need large resevoirs to work. Oil is heavy so imagine running around with gallons of oil on your bike. Unless there is some major breakthrough in technology, I don't think it would work.

phidauex

I think these folks are claiming a breakthrough in technology, not just a tiny hydrostatic drive off a snowmobile. Pump designs have changed a lot since the 20 year old hydrostatic cushman snow cat I used to have.

Two-pulley variable transmissions are cool (my scooter has one), but they have an inherent amount of slip (which is necessary, by the design), and so have a cap on efficiency.

I'd expect a system like this to be a solid/sealed system with a very small fluid level, not like a traditional hydraulic system. It could be a good thing (though again, I don't know the details of this system, so I'm not advocating it persay, just brainstorming).

peace,
sam

Avalanche325

I have trouble believing their effeciency ratings. I also like the statement that you don't need conventional brakes anymore. OK, so it can provide a rear brake. But, I'll keep my front brake, thank you very much.

It is a cool concept. But I don't think they will be riding them in the TdF anytime soon.

Imagine instead of buying a new chain and some cogs, having to have a hydraulic pump and hydraulic motor/transmission rebuilt?

JoeTown244GL

If it works as claimed, I'd buy one. I don't care how the power gets to the rear wheels. If it was monkeys passing Duracells back and fourth and they weighed less than my crappy Sora derailer then it would be alright with me. I'm not stuck on the technology. I'm stuck on the pedal=ride aspects of cycling.

One could even use the rear wheel stays as the fluid pipe route, thus saving weight. If the oil were flamable or even inflamable for that matter -- you could have an afterburner for the sprints.

Rev.Chuck

The pumps,one at wheel and crank, would look like this. Smaller of course. They have a plate that varies the volume of each piston pump. If you had each one as a variable pump/motor you could get a pretty good range of speed. The lines used for present hydraulic brakes would be strong enough and you would wnat to size them to the system anyway, no need to push extra fluid, resivior could be in the down tube.

Zouf

Some may remember, the hydraulic bike was my degree project in mech eng... So I find it quite funny to see someone pushing the idea all the way to prototyping (and a semi-serious attempt at marketing). All this aside, the pump/engine efficiency is the killer, pumping oil at low power is not a slam/dunk proposition. Don't hold you breath.

Dr. Moto

LOL @ "monkeys passing Duracells"

Brian

There are at least 2 manufacturers making DH bikes with gearboxes in the BB area, as opposed to derailleurs. And at least one rider has found that even a cheapo shaft drive system can be modified for pretty good results in DH racing. I'm skeptical of the fluid drive, but I expect to see the other things trickle into the mainstream soon enough. As a matter of fact, the shaft drive bikes require the Nexus 7 speed hub. Very clean setup.

bostontrevor

I've heard that Rohloff developed their hub for mountain biking, and DH more specifically. That's pretty wild if true.

Brian

It's the hot ticket for tandems. Hayes has been working with B1 on a gearbox too. Crazy stuff going on.

khuon

I'm waiting for the bicycle drivetrain that utlizes strong force to transmit power from the cranks to the wheel.

"Shimano is pleased to announce the introduction of the GluonDrive."

Brian

SRAM will do it first. Shimano has yet to get over the shame of their air shift system for DH racers.

khuon

Oh geez. Thanks for reminding me about the Airlines. I understand that system retailed for the measly sum of $2,000. You could only shift a couple of hundred times before the tank needed to recharged and I think it only operated the rear derailleur.