tag:blogger.com,1999:blog-7497191769424400596.post5532337496842064005..comments2024-03-05T00:21:36.018-08:00Comments on The Left-handed Cyclist: Graeme Obree's Beastie: The Lure of the Linear Pedal DriveHephaestushttp://www.blogger.com/profile/16913388668135150291noreply@blogger.comBlogger15125tag:blogger.com,1999:blog-7497191769424400596.post-27836775363918167642023-03-28T13:55:19.595-07:002023-03-28T13:55:19.595-07:00"and more significantly, in my opinion, he br..."and more significantly, in my opinion, he broke the record for a vehicle using a non-circular pedaling motion." This is not correct as Jan Bos went 78.59 mph with the K drive equipped Velox 2 in 2012. Delft/Amsterdam decided that the reduced efficiency was not worth it for the aero gains from a slightly more compact nose, and went back to conventional cranks the next year.jnyyzhttps://www.blogger.com/profile/13651185690685651207noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-7408389187853339702022-06-29T23:37:06.048-07:002022-06-29T23:37:06.048-07:00Thanks for sharing this with us! Some really amazi...Thanks for sharing this with us! Some really amazing features. <br /><i><b><a href="https://www.bestforminc.com/categories/tank-top.cfm" rel="nofollow">tank tops for men</a></b></i><br />Humaun Kabirhttps://www.blogger.com/profile/07115372749293027201noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-63668644085024537312022-06-06T04:19:13.446-07:002022-06-06T04:19:13.446-07:00If one is talking heavier but more streamlined vel...If one is talking heavier but more streamlined velomobiles; I would say that technology has moved on to electrically assisted biking with regen.<br />ie:<br />Elec assist with regen is very well suited to getting a heavier but way more aerodynamic, faster velomobile going, and then recuperating power during braking.<br /><br />The direct, long chained link to the wheels full of rollers and chain tubes has a lot of parasitic drag and weight vs a bicycle.<br /><br />Hence generating electricity from pedaling directly becomes worth considering:<br /><br />The Svea/Alenax system seems well suited to turning a generator, connected to the battery through a MPPT charger, with no reverse issues.<br /><br />Better yet may be linearly moving magnet/s past a linear coil..?<br />Perhaps each stroke could load (and release) a tensile spring/s that 'shoots' the magnet/s past the coil at the speeds required for efficiency..??<br /><br />A nice, self contained, system could be fitted to/in the passenger footwell of any EV or hybrid, by those looking to get a bit of exercise, with increased range to boot! :) Aldabrahttps://www.blogger.com/profile/02471978412789991107noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-64671848924116281722021-11-01T13:24:32.482-07:002021-11-01T13:24:32.482-07:00I do agree on the importance of training in the ev...I do agree on the importance of training in the evaluation of the two different pedaling systems. I noticed this on the linear pedals I built and after using them for a bit I got used to their cadence and I started switching leg pressure at exactly the correct treadle angle.Anonymoushttps://www.blogger.com/profile/03527981661468313985noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-71671331319562674282021-11-01T12:19:20.583-07:002021-11-01T12:19:20.583-07:00I would like to add that the whole point of the li...I would like to add that the whole point of the linear pedals for pedaling while standing uphills is to make the difficulty of the movement uniform for all grades of slopes. In the end you are repeating the same movement which is lifting your body weight on one leg and then on the other which means it's not your muscles that are pedaling, it's your body's weight that is making the pressure on the treadle. Basically it's the same as going up on a uniform stairs. The higher level you want to reach the more you're doing it but between every two steps you're making the same effort. Anonymoushttps://www.blogger.com/profile/03527981661468313985noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-21030143240658600452021-11-01T12:11:36.258-07:002021-11-01T12:11:36.258-07:00I am happy I found this thread.
Just for the reco...I am happy I found this thread.<br /><br />Just for the record, I built with machinists a treadle tricycle specifically for climbing uphills and high torque applications (moving cargo and operating machinery like a drill).<br /><br />I am testing it right now and I want to agree and disagree with some of the points mentioned. Circular pedaling bicycles depend heavily on momentum to surpass the weak spot and they are great at this. I do agree that their movement is smoother and easier on a flat plane and even on a shallow uphill but they do suffer from problems rarely discussed or mentioned.<br /><br />One of the problems of pedaling while sitting is that the position on the long run reduces the leg bone density because the movement is not load bearing and the calcium ends up leaving the body through sweat instead of solidifying in the bones. Another linear bike manufacturer (Streetstepper) claims pedaling while standing is also better for the back. Circular pedaling is not comfortable for pedaling while standing which is a claim not everyone agrees with. But even if enough people agree with it, it's probably a good reason to make linear pedals since they are very comfortable for biking while standing which is healthier and gives better torque output.<br /><br />Treadle bikes for biking while standing will have to use different gear ratios because there will be higher torque output but lower pedaling speed because I would use smaller back gears for the same uphill angle.<br /><br />I biked a lot and I climbed once 700 meters -in altitude- in the same day but I ended up walking with my circular pedal bike 90% of the time because I don't have a strong body. <br />This is why I built this tricycle. A tricycle means you can pedal slower uphill -because you don't have to keep your balance anymore- which means you can have much better endurance for long uphills. Add to that an anti-roll back freewheel and you don't roll back if you stopped pedaling uphill and didn't press the brakes which is pretty neat.<br />2-wheel bikes and circular pedals vs tricycles with linear pedals for uphills are like the difference between walking and running. The latter is faster but won't get you very far since it has pretty bad endurance.<br /><br />Linear pedals maybe won't increase your speed (but even this is debatable because linear pedals are easier to use while standing which means higher power output and with the right gearing, higher speed) but they will definitely help make the movement easier for pedaling while standing.Anonymoushttps://www.blogger.com/profile/03527981661468313985noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-30695638520574099722019-02-13T06:54:20.465-08:002019-02-13T06:54:20.465-08:00Hi Nathan, sorry for not getting back to you soone...Hi Nathan, sorry for not getting back to you sooner. Flywheels have been used on bicycles in the past and they can smooth out the pedaling dead spots. The two negatives are the weight of the flywheel and the flywheels resistance to changing pedaling cadence. A fixed gear gives a similar effect but they prevent changing gear ratios. You and experiment with changing your seat height to try and smooth out your pedaling. A lower seat height with more knee bend allows greater pedaling cadences which the more constant kinetic energy of the leg masses allows. Keep in mind that smooth pedaling has produced cadences of 6 revolutions per sec!Hephaestushttps://www.blogger.com/profile/16913388668135150291noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-58194194692511675682018-11-20T11:21:30.312-08:002018-11-20T11:21:30.312-08:00Oh, a bit got cut somehow. I was going to say tha...Oh, a bit got cut somehow. I was going to say that their testing was not very through though, testing only one type/format of CTT. And from appearances, a fairly inefficient design with very long treadles.Brown Cowhttps://www.blogger.com/profile/01864456559017567777noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-44852622948242381042018-11-20T11:10:45.888-08:002018-11-20T11:10:45.888-08:00I saw a paper on this, hold on a sec....
https://w...I saw a paper on this, hold on a sec....<br />https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1858725/<br /><br />There we go. It's by the University of Liverpool, Department of Mechanical Engineering (1979). The conclusion was that a Constant Torque Pedal system was 33% less efficient then the more common rotary action and that most of that loss was due to overcoming the legs own inertia and that of the long levers.Brown Cowhttps://www.blogger.com/profile/01864456559017567777noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-45034405909845232922018-04-17T19:23:38.172-07:002018-04-17T19:23:38.172-07:00I have a question for you all since you’ve obvious...I have a question for you all since you’ve obviously studied this much more than me. Was recently pedaling and was very annoyed by the dead spots at top and bottom of my stroke and the backlash I got consistently when I was not actively producing power in the crank cycle. It occurred to me that a flywheel linked to the crank would help carry through those dead spots and get us closer to the feeling of direct drive in place of freewheeling hub. Have people tried this? I imagine it would take extra energy to excite the freewheel, but would it pay off in helping to create a more consistent cadence and less strain on joints etc? Excellent article by the way!Nathanhttps://www.blogger.com/profile/16735025034718395884noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-47923583272793689052017-10-20T07:02:22.645-07:002017-10-20T07:02:22.645-07:00Thanks for your comment, and all those older desig...Thanks for your comment, and all those older designs names. I'll research all of that. I've added another comment below that you might like to read!<br />Maybe we could get in touch to develop something. ericoschmitt@yahoo.com.brÉrico Schmitthttps://www.blogger.com/profile/03533603772503931576noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-60436041081453862012017-10-20T07:00:13.913-07:002017-10-20T07:00:13.913-07:00I forgot to mention my design should be much light...I forgot to mention my design should be much lighter than all of those swinging arms, and more compact. Probably lighter than crank+derrailleur systems. And lower maintence. Sounds like magic, no? I believe in it, looking to make it become true. Érico Schmitthttps://www.blogger.com/profile/03533603772503931576noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-23515998938765831442017-10-20T06:56:57.211-07:002017-10-20T06:56:57.211-07:00I'm happy and sad at the same time for having ...I'm happy and sad at the same time for having found this article. Happy because its very informative, and sad because, again, I've invented something that (in a big portion) already exists.<br /><br />I have to disagree on efficiency opinions:<br />1) Cyclists trained for years on circular cycling said linear is about the same or inferior. But for a unbiased comparison one would have to train with both bikes for a whole year and test later. Or test with nin-cyclists athletes, like a runner who hasnt cycled for two years.<br />2) Leg muscle growth indicates inefficiency: new movement will use new muscle groups. A cyclist will probably notice if a non-cycling muscle starts to pop out. But he probably never realised how strong his glutes and quads already are! And calves, if you use your cleats close to the tip of the foot.<br />3)Lower cadence on linear bike: but consider also neuro-motor training. Ive been circular cycling since I was 4! I can spin 200rpm downhill on my fixie, and I can probably train to do the same linearly. Also I've rowed in the past, that probably will help the day I get my linear bike built.<br />4)If not using a fixed gear system, each side would waste energy in the begining of each stroke as the freewheel engages again, because the wheel is spinning fast and the leg has stopped: I like the spring idea! But maybe you don't need it to start compressing in the middle of the stroke, but more towards the extreme. Also there are non linear springs (conical springs) that have even more compression force the more they get compressed. So you can play with that to fine tune the most efficient spring setting. But I have to question if this engagement delay is really a big problem, because theres also no resistance force. Circular cycling also has those dead spots where you are not really pushing any power, just moving the crank along until it gets to 1 o clock so that you can push it hard again. How many people really "pedal in circles" all the time? I only do it sprinting or hammering uphill on a big gear. You can also build a linear path that is much longer than anyone will actually push. So the feet will just stop and move back because your leg isn't longer and you dont want to hit your knee on your chin.<br /><br />Finally, I said that i have, in a big part, reinvented linear drive. But I have something new, even after reading this article. I won't get in detail here for now as I have some more resarch to do - you never know if your idea doesnt already exists.<br /><br />But I can add what features I belive my system can achieve, if it works as intended, even considering the problems above:<br />-CVT transmission. Probably automatic and electronic will actually work better and easier, but i have to hire an electronic engeneer to help me with that... $$$. A mechanical CVT for my idea actually seems to be more complicated to build.<br />-Ridiculously wide range: above 600%, maybe as much as 900%, without any efficiency change throughout the range (eg: NuVinci CVT hub wastes energy on the top range. Rohloff or nexus only has no waste on 1:1 ratio).<br />-Power modulation throughout the stroke: the beggining will be lighter to push, as the bent knee has less power. The bottom will be harder to push, as the extended leg is much stronger. I still have to research what is the proportion if this strengh difference for a kneew angle function. This is similar to that added spring idea, but adressed in a very different way. Still my design might benefit from a smaller spring added just for a little help in the extreme of the movement ti shift direction of feet, or avoid harsh impact.<br /><br />That's it for now. But if you want to get in touch, ericoschmitt@yahoo.com.br<br />Érico Schmitthttps://www.blogger.com/profile/03533603772503931576noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-49505780146037286422015-01-04T20:34:48.765-08:002015-01-04T20:34:48.765-08:00After studying treadle & linear bicycle mechan...After studying treadle & linear bicycle mechanisms for a quarter century, this is the finest article on the subject I've had the pleasure of reading. Hopefully, this is just the beginning of the discussion and not the end.<br />I should hope this will expand into the analysis of sinusoidal and linear "motion," and everything in between... and the analysis of sinusoidal and linear "function," and everything in between. The piston and crank with a cross slide is an example of the piston in linear motion, but still stuck in the sinusoidal function due to the rod and crankshaft. Graeme Obree's Beastie elliptical pedal motion is “in between” linear and circular, leaning more towards the linear, but it is still converted into a sinusoidal function working through a crank. <br />Since my prosthetic knee barely hinges ninety degrees, I'm no longer able to ride crank bicycles, but I can ride faster, farther and easier on my Alenax bikes. It is equivalent to pedaling from the 2 oclock to 5 oclock position, the "sweet spot," and not the whole 12 to 6 o'clock sine function. It has good power delivery the full stroke, which is a pleasant feeling. There's no denying, there's more area under the curve of a square wave than a sine wave, ergo, more work output for given thrust.<br /> For a decade or so, I had the pleasure of switching from my Alenaxes, mountain bikes and my Columbia 10 speed, so the different performances could be compared. The Alenax is more efficient, for the most part, but it has a number of failings- good design but poor execution. It may fall under the category of constant torque, but the short treadles are are still handcuffed to the sine wave. The lower 2 speeds drop down more into the 3 to 6 o'clock range and can be frustrating. The Alenax is nearly a clone of the Svea, Northfleet, Levocyclette and the Harris bicycles. The Harris MK 2 has been the most inspirational for my concept of a continuously variable speed long-treadle drive for an upright bike. I still study the 25 year old gray printout off the USPTO microfilm. <br />I disagree with the argument the reciprocating linear motion is inferior to a constant circular motion, and in fact, it is probably the other way around. Using the Alenax/Svea treadle vertical motion for example, it is obvious pedal movement stops at the top and bottom stroke, BUT, the all important “vertical component” of the crank pedals likewise reach zero speed. The crank will accelerate slower in the vertical direction than the treadles, because it is locked into sine function. The momentum of the leg will actually be less for pure vertical movement since it doesn't have the parasitic horizontal momentum of the lower leg. The idea there is a great deal of wasted horizontal motion with the crank is NOT an advantage. Treadles also offer the advantage of electing a shorter stroke for a break from long leg movements. <br />I've long planned to get into production with a long-treadle wedgie with continuously variable speeds, but have since elected to fabricate a continuously variable speed linear drive recumbent (no crank, derailers, forks or steering column) to test out the concepts with superior performance over the upright. Someday!<br /><br />JIM.... another left-handed cyclist <br /><br />(this reply was previously deleted in order to edit it)Anonymoushttps://www.blogger.com/profile/14733697708697298609noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-65817715111126525182015-01-04T19:40:30.327-08:002015-01-04T19:40:30.327-08:00This comment has been removed by the author.Anonymoushttps://www.blogger.com/profile/14733697708697298609noreply@blogger.com