Electronic gear shift for bicycles

zogger

Sat Aug 02 19:22:06 -0700 2008

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You are a very decent pedaler. That's hauling @$$ets. With that said, not trying to change the subject but to offer an alternative to that, back when I built my prototype mountain bike and the design apparently got "borrowed" by a big bike factory the next little town over, the tards didn't realize that was only the freekin easy and stupid half of the design, the cool part, which I was carefully and sneakily having built by different guys at different shops so they wouldn't bingo to what I was doing I just stopped developer work on, was *hydraulic drive*. Unlimited ranges and gears, totally enclosed system. You could even make it with regenerative braking and coasting for a fast powerful boost for uphill and from dead stop situations, and use the internal frame structure for a lot of the reservoir you would need. Plus make it two wheel drive fairly easily. Like you, I think cables and chains are sorta 18th century old tech, because they just stretch and get dirty and get sucky. I guess some guys really like electronics, and this new shimano stuff is dang nice, I used a lot of dura ace way back, never could see any advantage of note with campy for the price, but I like simpler tech and more robust, electronics are always the major weak points on moving machinery out in the dusty and rainy real world, little bitty do dads get a bad connection and it ruins your whole day.

Electronic gear shift for bicycles

Michael Smith

Sat Aug 02 20:53:34 -0700 2008

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I took my current mountain bike to the Mallee shortly after I bought it and totally destroyed the driveline. I eventually got rid of the cluster and chain because it got covered with sand and basically eroded the moving parts away.

So anything which puts the moving parts inside away from the dirt is a good thing. I wonder how much efficency you can get out of hydraulics?

BTW I submitted a story about the Falcon 1 launch but it is out of date now because the launcher worked perfectly. You could probably drop that one if it hasn't been posted yet.

Electronic gear shift for bicycles

John Dalton

Sat Aug 02 20:55:58 -0700 2008

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What was the efficiency of your hydraulic drive zogger? Did it end up in any product?

I'm quite interested in alternative drive systems for bikes. I haven't built anything yet, but have done lots of back of envelope sketches and calculations. With my background being electrical engineering I would dearly like to experiment with an electric transmission on my bicycle. CSIRO have built a motor with 98% efficiency. They have even made limited technical details available. Perhaps it is possible to build a scaled down version of this motor and put two back to back, one acting as a generator. Pedals go on the generator and the motor goes on the wheel. Voila! Electric/electronic transmission with an efficiency of 96%, comparable to a chain drive. I'm not not sure if CSIRO's numbers include losses in the electronics and how their "best case" numbers relate to reality.

Once a bike has electric drive, why not make it intelligent? Regenerative braking is an obvious addition but why stop there? Why not add control systems to make the regen. automatic, decoupling the rider from the terrain? The rider pedals at a constant (optimal) cadence, generating constant power, equal to the average power required for the trip. The transmission matches the average power to the instantaneous power requirements.

How about we put the electric transmission on a unicycle? We add an angle sensor to the unicycle and the transmission is now responsible for doing all the fiddly pedaling to keep the unicycle upright. Not that much different to Trevor Blackwell's effort, except this one would still be human powered. Next step is to add a weight to the unicycle, rotating in a horizontal plane. The weight is driven by a stepper motor, under computer control. Now the computer can steer the unicycle and we have a unicycle that is stable in both front/back and left/right directions. Blackwell's is only stable front/back and requires the same level of skill as a normal unicycle to stop it from tipping left/right.  Would this one be ridable by an unskilled person?

The end result is a pole with a seat and pedals. You sit on the seat, in the same manner as you might sit on a bar stool. Put your feet on the pedals, turn them at a constant rate and off you go. Easier than riding on a bike, since you can't fall off and you are cycling on perpetual (virtual) flat terrain! If the automatic control systems can be made to have a faster response time than a human then why not make the wheel as small as possible, keeping in mind that is has to be big enough to go over rough terrain? That way the whole thing could be folded up and carried like an umbrella.

Continuing the thinking aloud... Let's replace the wheel with a ball. The ball can be driven in two axes: front/back or left/right, a bit like an oversized mouse ball in reverse, with the ball being driven by the "mouse". Maybe the ball can actually be the rotor of an induction motor, a two dimensional version of Tesla's Egg of Columbus?

I'm sure there are lost of holes in this (eg. final idea would require extremely strong fields to get decent torque), but it would be interesting to see how much of it could be built. I reckon it is probably all realistic apart from the final paragraph, the biggest unknow being whether the efficiency could approach that of a chain/sprocket transmission.

Electronic gear shift for bicycles

Michael Smith

Sat Aug 02 23:20:29 -0700 2008

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The rider pedals at a constant (optimal) cadence, generating constant power, equal to the average power required for the trip.

It would be handy to not have to stop working at red lights. My pulse rate tends to drop if I have to wait more than a couple of minutes at a time and then it is hard to get going again. Thats why runners tend to jog on the spot when waiting to cross the road.

Electronic gear shift for bicycles

rubycodez

Sun Aug 03 10:38:13 -0700 2008

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i'd just like to see more CVT on bikes, but there are  just a few (unecessarily) expensive systems out there for the high end rich snooty types, I just hate the derailleur thing.  Cause of all my troubles....

Electronic gear shift for bicycles

Stowe

Tue Aug 05 05:31:20 -0700 2008

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Bicycling is my main means of transportation and has been for 35 years.  Anyone who really rides regularly knows that the constant adjustment needs and vulnerability of derailleurs (I've used them all) is one of the main barriers to broader adoption of the most efficient and healthiest way to travel.  For about a year I have been riding a bike with the new 'Nuvinci' CVT, am quite happy with it and think this is the first 'alternative' transmission system that has a chance of persisting in the market (although the current weight will limit it in the beginning to serious commuters).  http://www.bikecommuters.com/2007/09/29/nuvinci-hub-review/

Electronic gear shift for bicycles

Champs

Sat Aug 02 22:09:12 -0700 2008

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Electric shift systems of the past have been design failures, but there's a compelling reason to make it happen, and it has everything to do with the complaints already put forward.  In a traditional system, you set the low and high limits, then get the tension just right so when you throw the lever, it moves the cage over X millimeters and cross your fingers that it's gone just far enough, no more or less.  The electric system knows where the top is, and moves the derailleur cage until the chain engages the next requested cog.  When you're nine shifts down from the top (on a ten speed cassette), you've obviously hit bottom.

This is simple embedded programming (that has taken years to develop, I'm quite aware), and could probably evolve into an autoshift program that the market could actually accept (if CVTs don't catch on).

Electronic gear shift for bicycles

Alcibiades

Sun Aug 03 00:37:44 -0700 2008

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On an individual level, its an interesting project/product.  On a social scale, in view of the role of the bike in what is coming towards us, its irrelevant.  We had many years ago transmission systems which had evolved to be fit for all weather commuting. 

The first thing is a fully enclosed chain.  This means that it doesn't get grit in it, lubrication lasts, reliability is greatly increased.  The second thing, of course, if you have a chain enclosure, you can no longer have derailleurs.  So you have hub gears.  This limits the number of speeds, but it doesn't much matter in ride to work scenarios for the masses, because 99% of the people will be riding on terrain without extreme hills.

The comments on this thread about shifting issues and wear of sprockets are thought provoking in this connection.  One can see why click shifting occurred - its because of the effort to make derailleurs usable by a mass public that will not listen to the bike and know when their shift has gone a bit too far or not quite far enough, and adjust till its silent.  But its the result of making a technology which is optimised for racing into a mass market transport technology.  I can see why they went for click shifting, but its halfway to the real solution, and if you are used to derailleurs, listening to the bike, remembering where you are in the gears, making the fine adjustment, click shift is infuriating.

For mass commuting, hubs are the optimal solution, given the requirements, not all of which are about cycling feel and pedalling cadence and speed.  Its like automatic transmission for driving in traffic.  Its just so much simpler when you are getting from A to B with as little thought as possible about how the vehicle is working.

As to weight:  I doubt that even 10% of professionals in blind tests could tell one case from the other, when the difference in weight of the e-version from the standard version is 70gm.  Weigh it in your hand, its under 3 ounces.  In commuting use, no-one will notice.  In fact, in commuting use, probably steel should replace alloy for lots of parts.  Stronger, wears better, if it gets bent, its easier to straighten, and the weight is immaterial.  There's also a lot to be said for steel rims and hub brakes, in an era of mass commuting.

Its going to be a different world.

Electronic gear shift for bicycles

GuyFawkes

Sun Aug 03 04:40:26 -0700 2008

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There are several issues here, I'll deal with them separately.

1. Chain and sprockets is the most efficient method of power transmission out there, and when you only have a couple of hundred watts of human power on tap, efficiency is king.
   
2. Chain wear is down to lack of lubrication and maintenance, period, I can get 25,000 miles EASY out of a relatively weedy 5/8" chain on a 1,000+ cc motorcycle, but the closest I have ever seen a pushbike owner come to "routine maintenance" is when they take the whole bike back to Richards for a service maybe once a year.
   
3. As someone else said, enclose the chain and it will effectively last a lifetime, enclosed chains make derailleur tough to do but as they say, 3 or 4 speeds are enough for any road bike.
   
4. Of the three pushbikes in this family one is a 12 speed and two are 18 speed, most of these speeds are literally never used.
   
5. On motorcycles cables worked for years with no problems, because unlike the crap fitted to bikes the cable was entirely enclosed from end to end.
   
6. On motorcycles the device that the cable plugged into was designed with some care, both to protect the cable, maintain minimum radius, keep egress of dirt away, and so on and so forth, so a periodic oiling was all it ever needed... please note we did this with 1960's era lubricants, oil in other words.
   
7. On motorcycles cables were NEVER used in the same way, eg they were NEVER used to position something like a gear selector, if you are going to use a cable for a gear selector you must always use two, when japanese motorcycles did away with the slide carb they introduced twin cable throttles, one cable to open the butterflies and the other to close them, and the tension between the two was balanced.

SO basically all the "problems" associated with bikes, which are evidenced by two out of the three bikes in this household, eg the two that are not maintained properly and which have not been modified properly (that bike is used daily all weathers, and has never once failed in operation in 4 years of daily use, and it was bought from Richards second hand for 60 quid) are down to one thing, piss poor design and piss poor quality.

The two crap bikes have sprockets cut from what appears to be recycled aluminium, the roller chains themselves are generic and piss poor quality, ditto the cables and ditto the cheap and nasty plastic cable controllers / gear selectors, likewise the derailleurs themselves are cheap and nasty, plus as mentioned above there are several basic fundamental engineering design flaws, put it all together with users who lack clue #1 about maintenance and you get what you get, a pile of crap and people casting about for alternatives.

You don't NEED alternatives.

A good quality derailleur running good quality sprockets and chains (and bearings) and a good two wire selector mechanism will work as smoothly and as trouble free as a dream, and with minor regular maintenance you'll wear out several tyres and sets of brake pads before you replace anything in the drive train.

Pop into richards (url below) and he can sell you all the fancy crap, but he also builds stuff and services stuff for customers, using all these "obsolete" technologies, and I'll tell you it works as smooth as silk (lot better than the girls bike for instance) and is a mechanical joy to behold, effortless, damn near silent, and highly efficient.

http://www.richardsbikes.net/index.htm

Electronic gear shift for bicycles

rubycodez

Sun Aug 03 10:49:50 -0700 2008

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that's great, and the other thing that needs to be thrown in the garbage are rim caliper brakes.