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Old 08-20-11, 12:48 AM   #1
crnlmushroom
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Hydraulic Shifters

Hey yall, I have to do a science project for my school (junior in high school) and im an avid bike mehanic and recreational road biker. To be honest im a better mechanic then i am a rider haha, and recently while looking at the newest innovations in the bike world i stumbled upon shimanos patent for hydraulic shifting but the mechanism was inefficient and poorly designed. I can strip a bike down and build it back up, ive restored countless old bikes, and i just recently built my own frame, so i figured id have a crack at this hydraulic shifting business. After a lot of designing and finding of various parts (its nearly impossible to find cylinders that small) i think i have a pretty good prototype, it uses a master piston and hydraulic multiplication to move smaller slave pistons. I originally used steel but it was too heavy so i just bought some aluminum to use. It also uses pivot arms and one double action piston per derailleur. With the aluminum it should be a bit lighter than your average shifter apparatus (those cables and housings add up after a while compared to the hydraulic hosing) and i found its much more efficient, not too mention its frictionless and much more rugged. Its got a lot of work till its finished cause getting the actual shifter to index and do it right is a bit tricky, but i think its going to have a lot of potential when its done. Ill post pics eventually but its pretty fugly looking right now, not to mention the rear derailleur is basially a hacked up shimano altus derailleur (ill make my own eventually). Just wondering everyones thoughts on the project and hydraulic shifting in general, any comments would be apprecated!
-Thanks yall sincerely John
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Old 08-20-11, 01:17 AM   #2
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Already comercially available if you have the money, http://www.acros.de/PRODUKTE/SCHALTUNG:::3_134.html

For the road world, electric if the way forward, lighter and 2nd generation for 2012, MTB could go one of 3 ways, stay with cable, electric or hydraulic, for the majority of users, Shimano will decide this for them.
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Old 08-20-11, 09:03 AM   #3
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Already comercially available if you have the money, http://www.acros.de/PRODUKTE/SCHALTUNG:::3_134.html

For the road world, electric if the way forward, lighter and 2nd generation for 2012, MTB could go one of 3 ways, stay with cable, electric or hydraulic, for the majority of users, Shimano will decide this for them.
The majority of people, like myself, dont have 2 grand to spend on just shifters lol thats why i was trying to make something a bit more affordable.
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Old 08-20-11, 12:33 PM   #4
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A good project would simply be a cable actuated master piston controlled by an exising indexed cable shifter, and a second cable actuated by an identical slave cylinder at the derailleur... then you don't need to worry about multiplication or indexing as it is built into the shifters.

Edit -

Some sort of similar system was manufactured and sold about a decade ago. I remember seeing ads in cycling mags, but I guess it never caught on.
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Old 08-20-11, 01:13 PM   #5
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It's a cost/benefit issue, and if you can solve actual problems with cable shifters then you'll have achieved something. Keep in mind that unlike brakes where you're transmitting force, in derailleur systems you're mainly transmitting position, so the real needs are different and a low pressure system might make sense.

You have a few challenges regarding to whether it's practical and cost effective.

1- cable systems are amazingly weight efficient, especially those which use the frame as the compression member and save housing weight.
2- ovalization- Depending on the properties of the lines, you might get ovalization when flexed, which changes the housing volume, and might be enough to cause ghost shifting.
3- hysteresis- Most hydraulic systems have a decent amount of hysteresis, and that would probably be worse for narrow lines. This might cause sluggish return shifting, rather than the very fast, crisp shifting folks are used to.
4-ease of service, especially field service- it's hard to beat a cable and pinch bolt for field serviceability.

I wish you luck with the project even if it's only a demonstration project. You might also consider a hybrid system, with cables down to the chainstay, or a straight path to the RD, where a hydraulic actuator moves the RD. The shorter lines wiuld help eliminate hysteresis, and you'd solve the worst of the cable friction problem, which on the 180 degree RD housing loop.
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Old 08-20-11, 11:15 PM   #6
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Lardasse, i like the indexed shifter attached to the master cylinder idea that would certainly make things easier to set up, perhaps a cheap set of bar end shifters would work pretty well being so small and all and having friction mode. Though having a wider bore master cylinder and using hydraulic multiplication (which is actually just a simple volume displacement problem) is actually a more efficient way to go i believe since it allows a shorter stroke distance per shift which allows for a more compact and efficient shifter not too mention probably crisper shifting. Though as for the derailleur i dont think having cable AND a cylinder would be a good idea because of the added weight and i feel like it kind of defeats the purpose of the precise hydrualic actuator if you use a regular cable derailleur.
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Old 08-20-11, 11:52 PM   #7
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FBinNY, I dont think weight will be a problem because the use of hydraulic cylinders makes many parts unnecesary including the stiff and heavy return springs and return related parts, the extra weight of the cylinder is easily negated by the loss of these parts. And as far as cables and housings go, the hydrualic hose and its fluid (mineral oil seems to be the lightest acceptable fluid though some fact checking needed there) are roughly equal to the weight of the cables and housings, though it depends on how much housing you use in your bike. Well i asked the company i bought the hosing from about ovalization and they said it wouldnt be a problem with the hosing im using (some type of low pressure thermoplastic hosing). Hmm i hadnt thought about hysteris ill have to think about that one. My idea to minimize the hysteresis and slop in the cylinder was to have two lines but rather than have a push push system use a push pull system so that each time the piston moves its getting pulled and pushed in that direction, i think those two forces moving the piston should help crispen up the shifting and provide a relative amount of stability to the system. Also i should mention i was thinking on using a low pressure system so that the user could easily use a syringe or something similar to insert the hydraulic fluid on the go if it sprung a leak. Which a bleed valve/insertion valve wouldnt be hard to incorporate at all fixing a leak would be similar to fixing a flat. And a simple piston lock would allow the user to lock the derailleur in any desired gear in case of complete hydraulic failure. As for temperature I dont believe the volume of the mineral oil will change to much due to its properties? but i could be wrong there, then again thats what the bleed valve/insertion valve is for in the case that the pressure isnt quite right
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Old 08-20-11, 11:54 PM   #8
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Thanks for the replies and ideas guys! All the comments are very helpful, and if i cant seem to work out the kinks in the system i might end up with a hybrid system like many of you are suggesting
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Old 08-21-11, 01:07 AM   #9
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The majority of people, like myself, dont have 2 grand to spend on just shifters lol thats why i was trying to make something a bit more affordable.
I clearly pointed out that it was expensive, but it's not a lot more than DI2 is , and as the technolgy matures, the price will come down, if you were making a prototype for a commercial application, not a student project, then the development costs will be in the tens to hundrends of thousands.
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Old 08-21-11, 05:44 AM   #10
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What the world really needs is a hydraulic brake lever for drop bars, with variable indexing for all systems. Go to it.
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Old 08-21-11, 06:06 AM   #11
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What the world really needs is a hydraulic brake lever for drop bars, with variable indexing for all systems. Go to it.
Hope have been working on a prototype adaptor for this, would expect Shimano to bring one out in the next few years as well http://www.singletrackworld.com/2011...-a-photo-tour/
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Old 08-21-11, 08:03 AM   #12
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As long as you use a two line system vs a one line against a spring return, hysteresis won't be an issue. The shifting force exerted by the rider is more than enough.
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Old 08-21-11, 09:50 AM   #13
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I clearly pointed out that it was expensive, but it's not a lot more than DI2 is , and as the technolgy matures, the price will come down, if you were making a prototype for a commercial application, not a student project, then the development costs will be in the tens to hundrends of thousands.
a commercial application also involves mass producing hundreds of thousands of units which really turns it into a completely different problem. Though if all works out i do plan to put them on my trek mountain bike afterwards, complete hydraulic brakes and shifters = a very rugged system
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Old 08-21-11, 09:53 AM   #14
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haha maybe thatll be next years project lol
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Old 08-21-11, 10:16 AM   #15
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a commercial application also involves mass producing hundreds of thousands of units which really turns it into a completely different problem. Though if all works out i do plan to put them on my trek mountain bike afterwards, complete hydraulic brakes and shifters = a very rugged system
Commercial viability does not require mass production. THere have been many companies over the years who make low-volume bicycle drivetrain parts, although most have gone out of business or switched focus. If it takes ~3 hours in a machine shop to make your part, and people will pay $300 for it (which is not an unreasonable price for a fancy piece of bike equipment) then it could work.
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Old 08-21-11, 10:46 AM   #16
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Commercial viability does not require mass production. THere have been many companies over the years who make low-volume bicycle drivetrain parts, although most have gone out of business or switched focus. If it takes ~3 hours in a machine shop to make your part, and people will pay $300 for it (which is not an unreasonable price for a fancy piece of bike equipment) then it could work.
I guess thats true but thats my point low volume bike parts have gone out of style. Though the actually process to machine is essentially the same as any other derailleur on the market and the cost of 300$ could actually be easily attained with wholesale hoses and cylinders, especially with the resources that a big company like shimano has. Not to mention it sure beats the 2 grand pricetag of the Acros shifters

Last edited by crnlmushroom; 08-21-11 at 11:00 AM. Reason: extra info
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Old 08-21-11, 10:51 AM   #17
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As long as you use a two line system vs a one line against a spring return, hysteresis won't be an issue. The shifting force exerted by the rider is more than enough.
Thats good to hear. Well i originally had planned for a one line spring loaded cylinder but i think the two line system will provide a much more crisp actuation which would be very precise do to the lack of spring which takes one more variable out of it. Im wondering if a high enough pressure can be achieved with a syringe and insertion valve though not sure how much psi can be achieved by hand.
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Old 08-21-11, 10:58 AM   #18
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I guess thats true but thats my point low volume bike parts have gone out of style. Though the actually process to machine is essentially the same as any other derailleur on the market and the cost of 300$ could actually be easily attained with wholesale hoses and cylinders, especially with the resources that a big company like shimano has.
My orginal point was that there was one availabe to buy off the shelf today; yes, you need a lot of money for it, but that's the same as a lot of limited production / cutting edge parts. Not sure then why it got in to an argument about manufacturing, but that tends to happen here on BF forums.

For low volume parts going out of style, see Paul Components, http://www.paulcomp.com/ low volume boutique from BITD, and still going.
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Old 08-21-11, 12:04 PM   #19
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... Not sure then why it got in to an argument... but that tends to happen here on BF forums...

No it doesn't!!!!!!11
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Old 08-21-11, 12:20 PM   #20
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No it doesn't!!!!!!11
Of course it does, you .....!!!!!!
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Old 08-21-11, 12:24 PM   #21
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The majority of people, like myself, dont have 2 grand to spend on just shifters lol thats why i was trying to make something a bit more affordable.
You cant start a company needing several CNC machines for 2K

Low cost, at retail, allowing markups at several distribution layers,
is why the volume of parts come from Low wage Asia in a currency
kept at a low exchange rate ,
Rather than High wage Germany, in a country with a exchange rate
that takes more USdollar-cents to buy a Euro.

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Old 08-21-11, 12:31 PM   #22
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My orginal point was that there was one availabe to buy off the shelf today; yes, you need a lot of money for it, but that's the same as a lot of limited production / cutting edge parts. Not sure then why it got in to an argument about manufacturing, but that tends to happen here on BF forums.

For low volume parts going out of style, see Paul Components, http://www.paulcomp.com/ low volume boutique from BITD, and still going.
Yeah, it's not that the low volume components have gone out of style, but that the low volume components don't work as well, in many instances, as the mass produced stuff. Paul's is a great example.. they sell a mount to install bar end shifters as top-mount thumbshifters, but they leave the actual shifting and indexing duties to the mass-produced components because they work so darn well.

THe old CNC derailleurs and shifter sets some companies were making may have been the cat's pyjamas in 1991, but Shimano introduced XTR components soon after and their performance was far and away better than anything that had come before. Same with cranks - a lot of companies were making and selling CNC machined crankarms, but they were not much lighter (if at all) than Shimano's offerings, and they weren't as strong.

The market is still open to any product that performs well or has features or performs a function the mass produced products do not... like Paul's brakes, Phil Wood and Chris King hubs, JTek IGH shifters and cable-pull adapters, (edit) and the Rohloff Speedhub.
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Old 08-21-11, 01:48 PM   #23
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Well l think, especially after having built them with minimal tools mostly a dremel rotary tool with different bits, that the hydraulic shifters would be no harder nor more expensive to make as regular cable derailleurs with some added benefits. Of course that's just the general idea without delving to much into specific things like manufacturing techniques and low volume vs high volume and types of labor which are irrelevant unless you guys want to make a company out of this project lol
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Old 08-21-11, 02:04 PM   #24
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I have no advice, I only wanted to say I think it's an awesome project for a high school junior. Keep your grades up, take the hard math courses, and one day you'll be building stuff for Mars missions. Go, kid, go!
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Old 08-21-11, 02:32 PM   #25
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Yeah, it's not that the low volume components have gone out of style, but that the low volume components don't work as well, in many instances, as the mass produced stuff. Paul's is a great example.. they sell a mount to install bar end shifters as top-mount thumbshifters, but they leave the actual shifting and indexing duties to the mass-produced components because they work so darn well.

THe old CNC derailleurs and shifter sets some companies were making may have been the cat's pyjamas in 1991, but Shimano introduced XTR components soon after and their performance was far and away better than anything that had come before. Same with cranks - a lot of companies were making and selling CNC machined crankarms, but they were not much lighter (if at all) than Shimano's offerings, and they weren't as strong.

The market is still open to any product that performs well or has features or performs a function the mass produced products do not... like Paul's brakes, Phil Wood and Chris King hubs, JTek IGH shifters and cable-pull adapters, (edit) and the Rohloff Speedhub.
The OP was saying that low volume have gone out of style, was just poining out they are still around, for the bike industry, anyone smaller than Shimano / SRAM / Campagnolo / FSA are small manfactures for parts. Using Paul is a bad example for shifting, as they were one of the few manufactures who put out a working front and rear derailleur, but in 1995, not 1991, and way after XTR was available.

For all boutique parts, a lot of firms which were making these parts went under in the late 90's when mountain biking's boom failed, not because they were making parts which wern't as strong as Shimano.
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