Results 1 to 88 of 88
  1. #1
    aka baycat
    Reputation: Ryan G.'s Avatar
    Join Date
    Aug 2004
    Posts
    8,484

    Power Curved Cranks...

    Was hoping for some Engrish but these awesome cranks will do. Anyone running them?

    via Bike Hugger



    "We have researched and road tested for the past 10 years and now we are very pleased to present you 2 types of power curved cranks. According to SGS Taiwan test report, power-curved crank canincrease 25~30% torque output between angle 0°(upper dead point)~60°.It has overcome technical difficulties on raising power efficiency in the bicycle industry for two centuries.

    Power-curved cranks use the design of golden spiral ratio, which create more pedaling efficiency than traditional cranks can provide, so that no matter bike lovers or normal riders can enjoy more fun of speed and comfortable riding. Also, its bright appearance and improved manufacturing process enhance the value and outstanding of the bicycle. For the purpose of meeting the commercialization, the power-curved cranks can be installed on any kind of bike without changing manufacturing process. Also, the power-curved cranks provide wider range of gear ratios for bicycle designing. In addition to those advantages, using power-curved cranks can increase 30% rotational momentum."

  2. #2
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    42
    no because the leverage point is the same.

  3. #3
    poser Administrator
    Reputation: rockcrusher's Avatar
    Join Date
    Aug 2003
    Posts
    9,039
    nice. How changing the shape of the arm increases output I don't understand but I can see how adding more material and using a square taper BB might be appealing to the Walmart bike buyer.
    Try this: HTFU

  4. #4
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    4,672
    Crap. Also, it's been done.

  5. #5
    mtbr member
    Reputation: twowheelsdown2002's Avatar
    Join Date
    Oct 2004
    Posts
    2,074
    Can't see how that would do anything.

    The leverage point is the same. The only difference is a small difference in the placement of mass, but I don't think that it would have any noticeable effect.

    If it did you could just place a weight somewhere on a standard crank set. It would have to be enough weight to give it a flywheel type of effect, and in order to be noticeable it would have to be more weight than you would want to add, and would probably make the pedal stroke feel herky jerky.

  6. #6
    Thread Killer
    Reputation: bucksaw87's Avatar
    Join Date
    Jun 2007
    Posts
    720
    well...i could see a longevity thing. if you have a problem with snapping regular cranks; with these, it looks like the force follows the curvature of the arm, so the force would stay in the arm all the way down to the BB
    I ride a 26'er with tubes and rim brakes.
    Yeah, I'm basically living in the stone age.

  7. #7
    Masher
    Reputation: MisterC's Avatar
    Join Date
    May 2007
    Posts
    1,426
    weigh?

  8. #8
    Stokeless Asshat
    Reputation: jeff's Avatar
    Join Date
    Jan 2004
    Posts
    3,348
    "Power-curved cranks use the design of golden spiral ratio"

    Says it all right there. No need to discuss any further.
    Zip ties? Not on my bike!

    Want:
    650B rims or wheel set. 80's vintage 32 or 36 x 135mm

  9. #9
    not really an mtbr member
    Reputation: theextremist04's Avatar
    Join Date
    Jul 2008
    Posts
    639
    Quote Originally Posted by baycat
    In addition to those advantages, using power-curved cranks can increase 30% rotational momentum."
    Only because they weigh so much more!

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jul 2004
    Posts
    1,149
    "All your torque are belong to us."

    -Som Ting Wong

  11. #11
    mtbr member
    Reputation: RedRider93's Avatar
    Join Date
    Sep 2007
    Posts
    186
    Rotor has one that works

  12. #12
    mtbr member
    Reputation:
    Join Date
    Nov 2008
    Posts
    1,498
    Designs like this come around every few years. They have zero benefit functionally, but are a good measure of the cultural memory span in the bike biz.

    In alternate years we get eliptical chainrings.
    fb
    www.chain-L.com

    The key to solving any problem is to understand and address the underlying cause.

  13. #13
    251
    251 is offline
    mtbr member
    Reputation: 251's Avatar
    Join Date
    May 2008
    Posts
    521
    Dave

  14. #14
    I Have Cookies
    Reputation: ae111black's Avatar
    Join Date
    Dec 2008
    Posts
    2,645
    I say the shortest distance between two points is a straight line
    The most important thing is what God thinks about it. He will have the final say.” – Joshua Stinebrink

    ____
    Kimo

  15. #15
    Thread Killer
    Reputation: bucksaw87's Avatar
    Join Date
    Jun 2007
    Posts
    720
    Quote Originally Posted by jeff
    "Power-curved cranks use the design of golden spiral ratio"

    Says it all right there. No need to discuss any further.

    the fibonacci curve is the "golden" curve

    yay for 11th grade math!
    I ride a 26'er with tubes and rim brakes.
    Yeah, I'm basically living in the stone age.

  16. #16
    Bicycle rider
    Reputation: ExigeS's Avatar
    Join Date
    Jan 2007
    Posts
    1,055
    Who stole my BS meter? Post pics if you purchase and install it on you bike.

  17. #17
    mtbr member
    Reputation: mtbykr's Avatar
    Join Date
    Feb 2004
    Posts
    445

    ya

    The nine most terrifying words in the English language are, 'I'm from the government and I'm here to help.' --Ronald Reagan

  18. #18
    mtbr member
    Reputation:
    Join Date
    Dec 2008
    Posts
    11

    even better...

    I've created one that's even better, the no dead point at all crank...


  19. #19
    I Have Cookies
    Reputation: ae111black's Avatar
    Join Date
    Dec 2008
    Posts
    2,645
    Spin people SPIN!!!!!!
    The most important thing is what God thinks about it. He will have the final say.” – Joshua Stinebrink

    ____
    Kimo

  20. #20
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    4
    increase 2-3 km/per hour,
    The Revolution(s) Per Minute increases 2~3 RPM

    Torque output efficiency increasing 25~30% test by SGS

  21. #21
    mtbr member
    Reputation: 006_007's Avatar
    Join Date
    Jan 2004
    Posts
    8,998
    Where can I buy these.

    Will they work with 83mm bb?

    I jump to flat lots, how high can I jump with these?

  22. #22
    Stay thirsty my friends
    Reputation: 4JawChuck's Avatar
    Join Date
    Nov 2008
    Posts
    885
    WTF they don't come in pink or purple? Everyone knows purple is the color of power...pffffft! Also according to Feng Shui the sprockets should be on the left side to provide life force balance, these guys are obviously amateurs if they don't understand these basic principles.

  23. #23
    mtbr member
    Reputation: peternguyen's Avatar
    Join Date
    Dec 2007
    Posts
    1,172
    Looks like a boomerang.

  24. #24
    mtbr member
    Reputation: hootsmon's Avatar
    Join Date
    Feb 2008
    Posts
    762
    Reading this thread, I just had a Brainstorm moment; why not bolt on THREE cranks, for a 50% torque increase?
    Brisbane, AU

  25. #25
    it's....
    Reputation: Strafer's Avatar
    Join Date
    Jun 2004
    Posts
    2,059
    Quote Originally Posted by hootsmon
    Reading this thread, I just had a Brainstorm moment; why not bolt on THREE cranks, for a 50% torque increase?
    Would only work for black guys.

  26. #26
    mtbr member
    Reputation:
    Join Date
    Sep 2007
    Posts
    169
    Quote Originally Posted by 251
    LOL you save $5 each if you get 5

  27. #27
    Seeeriously easy Livin
    Reputation: Flystagg's Avatar
    Join Date
    Nov 2006
    Posts
    1,864
    Some one else chimed in with suggestion already, buy Rotor cranks if you want to eliminate the dead spot, and gain a real advantage on tech climbs, I use them, and they work
    http://www.rotorbikeusa.com/

    and they were designed by engineers, not based on "golden curves"

  28. #28
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    4
    Hey Guys
    I just found the computation formula to calculate the curved crank's torque output
    Just see it



  29. #29
    All fat, all the time.
    Reputation: Shark's Avatar
    Join Date
    Feb 2006
    Posts
    7,235
    Quote Originally Posted by steiny
    "All your torque are belong to us."

    -Som Ting Wong
    lol sweetness.

  30. #30
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    7

    These Cranks Work

    I have built a Dual shock MTB that goesfaster than Road bicycles and weighs 18 kg !!
    It is the 2nd prototype I have built, the first still goes fine and the only problem I had in 5 years was a flat tyre and replaced rear derailer. it was a Dual shock 11-32t rear and 42-52t front chainrings. my new one runs 11-28t and 42-56t front and on my 3rd prototype i will changing it to 44-60t with a new crank arm, I combined two crank designs to make my upgaded model and it works perfectly, it cruises at 55+ kph and is so easy I can ride uphill using the 56t and still change gears at the rear. this is why I am going to a larger chainring setup on my next. the experts said it wasnt possible, but I have it, the bike shop call it Super bike. Heavy just means more momentum, its sad to see people so closed minded. I saw the potential even before my project was started and cant wait to show the Experts what else is really possible.
    Attached Thumbnails Attached Thumbnails Power Curved Cranks...-2nd-prototype-2010.jpg  


  31. #31
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,307
    Quote Originally Posted by SGT.MARSHALL
    I have built a Dual shock MTB that goesfaster than Road bicycles and weighs 18 kg !!
    It is the 2nd prototype I have built, the first still goes fine and the only problem I had in 5 years was a flat tyre and replaced rear derailer. it was a Dual shock 11-32t rear and 42-52t front chainrings. my new one runs 11-28t and 42-56t front and on my 3rd prototype i will changing it to 44-60t with a new crank arm, I combined two crank designs to make my upgaded model and it works perfectly, it cruises at 55+ kph and is so easy I can ride uphill using the 56t and still change gears at the rear. this is why I am going to a larger chainring setup on my next. the experts said it wasnt possible, but I have it, the bike shop call it Super bike. Heavy just means more momentum, its sad to see people so closed minded. I saw the potential even before my project was started and cant wait to show the Experts what else is really possible.
    Post this again on April 1
    mtbtires.com
    The trouble with common sense is it is no longer common

  32. #32
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    7
    I get the last laugh because I save 30% percent of my energy and still ride at higher speed than all you experts with all the comfort of a Dual shock and durability of a MTB, While all you experts are pedaling your guts out on your 22t/32t/44t uphill and on straights, I love laughing at you guys, legs going like egg-beaters.

  33. #33
    meow meow
    Reputation: b-kul's Avatar
    Join Date
    Sep 2009
    Posts
    10,622
    Quote Originally Posted by SGT.MARSHALL
    I have built a Dual shock MTB that goesfaster than Road bicycles and weighs 18 kg !!
    It is the 2nd prototype I have built, the first still goes fine and the only problem I had in 5 years was a flat tyre and replaced rear derailer. it was a Dual shock 11-32t rear and 42-52t front chainrings. my new one runs 11-28t and 42-56t front and on my 3rd prototype i will changing it to 44-60t with a new crank arm, I combined two crank designs to make my upgaded model and it works perfectly, it cruises at 55+ kph and is so easy I can ride uphill using the 56t and still change gears at the rear. this is why I am going to a larger chainring setup on my next. the experts said it wasnt possible, but I have it, the bike shop call it Super bike. Heavy just means more momentum, its sad to see people so closed minded. I saw the potential even before my project was started and cant wait to show the Experts what else is really possible.
    will these be for sale to the general public soon?

  34. #34
    Tool
    Reputation: Pedalphile's Avatar
    Join Date
    Aug 2008
    Posts
    1,973
    Quote Originally Posted by b-kul
    will these be for sale to the general public soon?
    Looks like something a security guard may take pride in owning. I'd start checking the back few pages of magazines no one reads if you're really interested in scoring something like this.
    I can barely get my mouth around it.

  35. #35
    mtbr member
    Reputation: s0ckeyeus's Avatar
    Join Date
    Jun 2008
    Posts
    2,686
    Quote Originally Posted by SGT.MARSHALL
    I get the last laugh because I save 30% percent of my energy and still ride at higher speed than all you experts with all the comfort of a Dual shock and durability of a MTB, While all you experts are pedaling your guts out on your 22t/32t/44t uphill and on straights, I love laughing at you guys, legs going like egg-beaters.
    No fair. Most of us actually take our bikes off the road.

  36. #36
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,307
    Quote Originally Posted by SGT.MARSHALL
    I get the last laugh because I save 30% percent of my energy and still ride at higher speed than all you experts with all the comfort of a Dual shock and durability of a MTB, While all you experts are pedaling your guts out on your 22t/32t/44t uphill and on straights, I love laughing at you guys, legs going like egg-beaters.
    Will look for you and your bike in the ProTour crushing Cancellara
    mtbtires.com
    The trouble with common sense is it is no longer common

  37. #37
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    7
    Quote Originally Posted by b-kul
    will these be for sale to the general public soon?
    I am in the process of design uprades to improve performance, after I will be selling to public worldwide at a fair price, I am not greedy for money and I beleive the average person should get quality product, I built mine for $2000-2500 AUD aprox. not including labour. if you are interested let me know

  38. #38
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    7
    Quote Originally Posted by shiggy
    Will look for you and your bike in the ProTour crushing Cancellara
    I would love nothing more than to personally see all the jaws drop when they get passed by a bike 2-3 time heavier but I have a spinal injury from the Defence force that stopped me for walking for 1yr and still havent got back full fuction. I am hoping to do the 200km ride for cancer in August 2011

  39. #39
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    7
    Quote Originally Posted by s0ckeyeus
    No fair. Most of us actually take our bikes off the road.
    This bike goes Off-road, its just faster going up and down with less wear on the rider

  40. #40
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,787
    The tapered and curved crank arms, if round, square, hollow, U-beam or I-beam could allow slightly less flex using the same material and weight as a round, square, hollow, U-beam or I-beam straight crank respectively due to a couple of factors I can think of...

    Similar to how thinner walled larger diameter tubes can be stiffer than thicker walled smaller diameter tubes of the same material in a frame or fork.

    The curved arms vs. straight increase torsional stiffness compared to a straight swingarm, similar to how some monopivot swingarms are designed with a tapered curve or "v" and the arms are larger near the monopivot axis to increase torsional stiffness.

    30%, near 1/3 stiffer?

  41. #41
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    7

    If you cant understand this, I am surprized you have the inteligence to login

    I made a picture for people who does have brain power to process the Curved Crank design, I know you can blame your school teacher all you want after ! Maybe one day you might trade up from the standard cranks and join the smart cyclists ! Put your money where your mouth is, it requires balls but it is possible
    Attached Thumbnails Attached Thumbnails Power Curved Cranks...-turbo-crank-explained.jpg  


  42. #42
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    874
    Quote Originally Posted by SGT.MARSHALL View Post
    I made a picture for people who does have brain power to process the Curved Crank design, I know you can blame your school teacher all you want after ! Maybe one day you might trade up from the standard cranks and join the smart cyclists ! Put your money where your mouth is, it requires balls but it is possible
    This has to be some of the worst physics I've seen. First off, don't you have to raise the same of mass on the other arm? (duh). Second, you're having to accelerate that mass every time you pedal, much like wheel weight. And third, you obviously work for the company that makes these judging by your engrish.

  43. #43
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    5,123
    I'm giddy with the amount of awesome that is happening right now.

    Flywheels for cranks, 60T chainring, efficient walmart bike, weight=momentum, pesudo-physics, this thing has it all!
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  44. #44
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    874
    According to your second pic, your magical cranks take no effort to turn! That's amazing!

    Also, according to your "theory", I should run the heaviest wheels possible and regain the 45 pounds I lost so I have more momentum.
    Last edited by ryguy135; 10-23-2011 at 03:06 PM.

  45. #45
    Class Clown
    Reputation: dundundata's Avatar
    Join Date
    May 2009
    Posts
    2,071
    yeah let's compare bike cranks to flywheels and exhaust systems!

  46. #46
    Tool
    Reputation: Pedalphile's Avatar
    Join Date
    Aug 2008
    Posts
    1,973
    "...weight that creates momentum."

    Classic.
    I can barely get my mouth around it.

  47. #47
    Flat six
    Reputation:
    Join Date
    Feb 2011
    Posts
    74
    As long as we're talking physics...


  48. #48
    mtbr member
    Reputation: Metalhack's Avatar
    Join Date
    Aug 2011
    Posts
    313
    With these cranks and my bio paced 3 ring circus I'm gonna rule the world!

  49. #49
    mtbr member
    Reputation:
    Join Date
    Aug 2008
    Posts
    4,805
    Would you guys stop making fun of SGT.MARSHALL. Obviously he is not a SHILL. he is forealz yo.

    SGT.MARSHALL: Where can i buyz one of these? I lost my right in the war and my left leg is not strong enough to ride anymore. I love riding so much but I just can't do it. From the science and graphs I saw on your website, I asked my physics friend if these works and he said yes. So for me to enjoy riding again, I would love to buy these. Just let me know where to send my hard earned money.


    Everyday I wake up an look at my Mongoose XR-7, I cry because I can't rise anymore. Please help me. Its so sad when I see my friends ride and they fun of me with one leg. I want to show it to them and be faster than them by %30!

    You the man SGT.MARSHALL

  50. #50
    mtbr member
    Reputation:
    Join Date
    Oct 2007
    Posts
    403
    Quote Originally Posted by Pedalphile View Post
    "...weight that creates momentum."

    Classic.
    Someone should alert Stockholm, this guy has managed to prove that mass=momentum. Genius.

  51. #51
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    7
    I didnt realise you guys still believe the Earth is Flat, sorry I wasted my time

  52. #52
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    874
    Quote Originally Posted by SGT.MARSHALL View Post
    I didnt realise you guys still believe the Earth is Flat, sorry I wasted my time
    What!?! Blasphemy!!

  53. #53
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,473
    Quote Originally Posted by SGT.MARSHALL View Post
    I made a picture for people who does have brain power to process the Curved Crank design, I know you can blame your school teacher all you want after ! Maybe one day you might trade up from the standard cranks and join the smart cyclists ! Put your money where your mouth is, it requires balls but it is possible
    As a fellow (former) 8th grade physical science teacher, I can empathize with the overwhelming depression and feelings of futility that your teachers must be feeling right now.
    Last edited by kapusta; 10-24-2011 at 07:07 AM.
    15mm is a second-best solution to a problem that was already solved.

  54. #54
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,473
    Quote Originally Posted by SGT.MARSHALL View Post
    I have built a Dual shock MTB that goesfaster than Road bicycles and weighs 18 kg !!
    It is the 2nd prototype I have built, the first still goes fine and the only problem I had in 5 years was a flat tyre and replaced rear derailer. it was a Dual shock 11-32t rear and 42-52t front chainrings. my new one runs 11-28t and 42-56t front and on my 3rd prototype i will changing it to 44-60t with a new crank arm, I combined two crank designs to make my upgaded model and it works perfectly, it cruises at 55+ kph and is so easy I can ride uphill using the 56t and still change gears at the rear. this is why I am going to a larger chainring setup on my next. the experts said it wasnt possible, but I have it, the bike shop call it Super bike. Heavy just means more momentum, its sad to see people so closed minded. I saw the potential even before my project was started and cant wait to show the Experts what else is really possible.
    Your front tire is on backwards.
    15mm is a second-best solution to a problem that was already solved.

  55. #55
    mtbr member
    Reputation:
    Join Date
    Feb 2005
    Posts
    781
    ^ I suspect it might be his brain that is on backwards.

    Back in ~1983 I went to a bike show in the UK and somebody there tried to convince me that the PMP cranks had more leverage than straght cranks; he failed. Nonetheless, one of the top time triallists at the time, Dave Lloyd, used these on his bike, presumably to psych people out. So, while they don't actually do anything useful, they aren't necessarily a disaster either, though I'd be worried about cracking through the "corners" myself...

    I've personally used Biopace and Cycloid chainrings, and (briefly) Powercam cranks, and can confirm that none of these really help either, and that the Powercams are the worst of the bunch, being heavy and unreliable as well. To be fair, Biopace rings required less pedalling technique and responded better to just shoving roughly downwards than circular rings, handy if one cannot spin.

  56. #56
    mtbr member
    Reputation:
    Join Date
    Feb 2011
    Posts
    51
    Quote Originally Posted by kapusta View Post
    As a fellow (former) 8th grade physical science teacher, I can empathize with the overwhelming depression and feelings of futility that yours must be feeling right now.
    Game Set Match

  57. #57
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,473
    Quote Originally Posted by satanas View Post
    ^ I suspect it might be his brain that is on backwards.

    Back in ~1983 I went to a bike show in the UK and somebody there tried to convince me that the PMP cranks had more leverage than straght cranks; he failed. Nonetheless, one of the top time triallists at the time, Dave Lloyd, used these on his bike, presumably to psych people out. So, while they don't actually do anything useful, they aren't necessarily a disaster either, though I'd be worried about cracking through the "corners" myself...

    I've personally used Biopace and Cycloid chainrings, and (briefly) Powercam cranks, and can confirm that none of these really help either, and that the Powercams are the worst of the bunch, being heavy and unreliable as well. To be fair, Biopace rings required less pedalling technique and responded better to just shoving roughly downwards than circular rings, handy if one cannot spin.
    The major difference between these cranks and bio-pace rings, is that bio-pace rings actually do something (for better or for worse).
    15mm is a second-best solution to a problem that was already solved.

  58. #58
    mtbr member
    Reputation:
    Join Date
    Feb 2005
    Posts
    781
    The cranks do something too: they look different. :-)

  59. #59
    mtbr member
    Reputation: s0ckeyeus's Avatar
    Join Date
    Jun 2008
    Posts
    2,686
    Name:  Untitled.jpg
Views: 610
Size:  19.1 KB

  60. #60
    banned
    Reputation: marpilli's Avatar
    Join Date
    Feb 2011
    Posts
    3,993
    Does that kickstand make the bike faster, too? If so, I want one.

  61. #61
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,473
    Quote Originally Posted by satanas View Post
    The cranks do something too: they look different. :-)
    Actually, on the right bike (some curvacious townie cruiser) I think the first one (upper left, without rings) would look kind of cool.
    15mm is a second-best solution to a problem that was already solved.

  62. #62
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    373
    It dumbfounds me that I still get dumbfounded when I see someone deliberately deceiving people in order to make money

  63. #63
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    4
    Those have opposition or think lever theory about curved cranks, if their viewpoint is correct, why people so surprise curved crank’s efficiency after riding.

    As I know the efficiency comes from the gravity of cranks forward , in other words, toe-out effect. The calculation formula is not using lever theory but using trigonometric function to calculate its effective force area

    According to maker’ data, they did integral calculation by every 10 degree then total work got 33% efficiency that is compared with traditional straight crank.
    On upper dead point , straight crank is vertical to axle ,so most of pedaling force are lost on this angle. However sickle crank not only center gravity forward but also effectively pass through upper dead point and reduce loss, so output increases by 33% compared with straight crank..


    My personal opinion

    There are two kinds of scientist since long time ago- practice and laboratory scientists.
    Science calculation is to explain nature phenomenon not simply to examine its possibility. The sickle crank’s efficiency is fact and proved. It is said that SGS was surprised, too when they got result.


    The follows comes from official website

    1. calculation formula( by every 10 degree)
    According to this data you can see torque output is bigger than straight crank before 160 degree and get more efficiency from 0 ~130 degree. Reduced force loss in the max pedaling force losing zone , so curved crank can get more torque output.
    Straight crank is better than curved from 160~180 degree , however, it is in the low pedaling force losing zone ,besides on 180 degree position , the other crank already on the 0 degree(upper dead point) to start new circulation.

    If using clipless pedal to pull from low dead point , the efficiency will be as same as 0~130 degree. One leg pedal and the other leg pull by clipless pedal , it will get multiple effect

    2.SGS Test report ( official website)

    3. USA Cyclist used computer trainer to test, AVE HR reduced 11 bpm,maximal oxygen consumption reduced 9%;MAX HR reduced 5 bpm,maximal oxygen consumption reduced 4%


    I installed one set. When pedal harder , I could feel the explosive power form rear wheel .If I constant speed ride , the pedal seems be driven by certain force and automatically pass through upped dead point.
    Some one had pedaled 53t gear and his rpm increased 20%. My experience is using front 56t and rear 11t , feel as same as 50 t gear. The speed is very fast and easy to reach 40km/h, well, because it is 56t. Some friends got good physical condition they could easy to reach 50~55km/h


    One of my riding course is 20km and 9.75km is a slope. The slope is average 3.5% and last 2km is 7.5% slope. It took 90 minutes to run this course, but used this sickle crank , it only takes 70 minutes. 20% faster.

    From these riding experience , I know it really get efficiency

    Sharing this information for you guy . If you want know more riding experience , you may check out official website.
    Attached Thumbnails Attached Thumbnails Power Curved Cranks...-chart01.jpg  

    Power Curved Cranks...-velologic_at-test-20w-every-1-min_curvedcranks_10-26-2009-1-30-pm-eng.jpg  

    Power Curved Cranks...-velologic_at-test-20w-every-1-min_straightcranks_11-10-2009-7-24-pm-eng.jpg  


  64. #64
    mtbr member
    Reputation: s0ckeyeus's Avatar
    Join Date
    Jun 2008
    Posts
    2,686

    No good

    <iframe width="420" height="315" src="http://www.youtube.com/embed/saalGKY7ifU?rel=0" frameborder="0" allowfullscreen></iframe>

  65. #65
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,473
    Quote Originally Posted by celine0711 View Post
    Those have opposition or think lever theory about curved cranks, if their viewpoint is correct, why people so surprise curved crank’s efficiency after riding.
    .
    The idea has been around for a very long time. There is one example shown above from 1983. If these actually do work as advertized, why has not a single competitive professional rider adopted these?

    I am trying to figure out if you are even serious

    You do realize that the table of torque calculations is complete nonsense, right? They don't actually tell you what they are plugging into the formulas. Thing is, they SHOULD be plugging in the exact same numbers for the curved and the straight cranks at each crank position, so the mathematical results should be the same. The fact that they are getting different values means they are plugging in different values. I can't believe I am even having to explain this to you.
    Last edited by kapusta; 10-31-2011 at 05:30 PM.
    15mm is a second-best solution to a problem that was already solved.

  66. #66
    mtbr member
    Reputation: s0ckeyeus's Avatar
    Join Date
    Jun 2008
    Posts
    2,686
    Shill.

  67. #67
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    5,123
    Quote Originally Posted by celine0711 View Post
    1. calculation formula( by every 10 degree)
    According to this data you can see torque output is bigger than straight crank before 160 degree and get more efficiency from 0 ~130 degree. Reduced force loss in the max pedaling force losing zone , so curved crank can get more torque output.
    Straight crank is better than curved from 160~180 degree , however, it is in the low pedaling force losing zone ,besides on 180 degree position , the other crank already on the 0 degree(upper dead point) to start new circulation.

    If using clipless pedal to pull from low dead point , the efficiency will be as same as 0~130 degree. One leg pedal and the other leg pull by clipless pedal , it will get multiple effect
    I took a look at the chart and did a quick calculation. I can't read Kanji but if I'm interpreting the chart correctly, the highest force shown is developed at 180° which is 1 N*mm. Run through the math of a force applied as if it were at the outer most point of the crank on a 170mm average crank length and assuming the force applied is not a distributed load across the crank arm (which is it, but let's assume best-case scenario). If you did that, (and if I did it correctly) then you would come out with 1 N*mm applying a 0.6g force.

    For reference, a sheet of standard printer paper weighs about 18g.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  68. #68
    Tool
    Reputation: Pedalphile's Avatar
    Join Date
    Aug 2008
    Posts
    1,973
    I just negative rep'd myself for being subscribed to this thread.
    I can barely get my mouth around it.

  69. #69
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    2,949
    They should make these out of depleted uranium. The efficiency would be off the charts and they would make your ankles glow!

  70. #70
    Flat six
    Reputation:
    Join Date
    Feb 2011
    Posts
    74
    Hey look, I can make charts and graphs and feel professional too!

    This thread:

  71. #71
    mtbr member
    Reputation:
    Join Date
    Nov 2008
    Posts
    424
    Quote Originally Posted by Pedalphile View Post
    I just negative rep'd myself for being subscribed to this thread.
    HAHA! Zing!

    /thread

  72. #72
    It's about showing up.
    Reputation: Berkeley Mike's Avatar
    Join Date
    Jan 2004
    Posts
    12,733
    Such genius is destined to go unrecognized by we troglodytes.
    Attached Images Attached Images  
    I don't rattle.

  73. #73
    mtbr member
    Reputation:
    Join Date
    Aug 2011
    Posts
    202
    Personally, if this thread never dies, I will die happy. It helps fill a very deep void.

  74. #74
    Carbon & Ti rule
    Reputation: muzzanic's Avatar
    Join Date
    Apr 2009
    Posts
    5,406
    Wow I didn't know George Bush had sterted building bike parts.

    Question is ??? Is this closer to the truth than anything else he has said ???????

    Sounds like 1 of his claims. Well if it wasn't for the fact it was only 30% out.
    I have a 6 Berth Motorhome that I rent out . It is based in Tauranga, New Zealand

  75. #75
    Can Tree Member
    Reputation: Dad Man Walking's Avatar
    Join Date
    Sep 2004
    Posts
    847
    I think that if you put these cranks on a bike that was running Sheldon Brown's POWerWheels the damn thing would coast uphill.

    I'm in.
    Dad is sad.
    Very, very sad.
    He had a bad day.
    What a day Dad had!

  76. #76
    mtbr member
    Reputation:
    Join Date
    Dec 2003
    Posts
    2,904
    You Muggles just don't get it. Obviously Celine and Sgt are graduates of the Hogwarts Academy and just applying what they learned with their degrees in the Dark Arts.

  77. #77
    mtbr member
    Reputation:
    Join Date
    Feb 2005
    Posts
    781
    Dark (or black) Arts sounds about right...

  78. #78
    banned
    Reputation: marpilli's Avatar
    Join Date
    Feb 2011
    Posts
    3,993
    I heard that polishing your crank can cause hairy palms...

  79. #79
    Huckin' trails
    Reputation: David C's Avatar
    Join Date
    May 2011
    Posts
    5,848
    Are these 29er's compatible ?
    Quote Originally Posted by NicoleB28 View Post
    topless. that's what all mtb girls do. we go ride, get topless, have pillow fights in the woods, scissor, then ride home!

  80. #80
    mtbr member
    Reputation: s0ckeyeus's Avatar
    Join Date
    Jun 2008
    Posts
    2,686
    Quote Originally Posted by David C View Post
    Are these 29er's compatible ?
    Yes, but you'd have to run them backwards to counter-balance the momentum of the bigger wheel.

  81. #81
    Huckin' trails
    Reputation: David C's Avatar
    Join Date
    May 2011
    Posts
    5,848
    Quote Originally Posted by s0ckeyeus View Post
    Yes, but you'd have to run them backwards to counter-balance the momentum of the bigger wheel.
    Thanks, good to know. But what if I run them with power-curved mag type wheels ? Do I get like 66% more power from 2 power-curved rotational mass and a 29" wheel ?
    Quote Originally Posted by NicoleB28 View Post
    topless. that's what all mtb girls do. we go ride, get topless, have pillow fights in the woods, scissor, then ride home!

  82. #82
    poser Administrator
    Reputation: rockcrusher's Avatar
    Join Date
    Aug 2003
    Posts
    9,039
    Quote Originally Posted by SGT.MARSHALL View Post
    I made a picture for people who does have brain power to process the Curved Crank design, I know you can blame your school teacher all you want after ! Maybe one day you might trade up from the standard cranks and join the smart cyclists ! Put your money where your mouth is, it requires balls but it is possible
    Isn't the weight backwards on the opposing sides crank arm? Wouldn't that negate the effect that you highlighted for this crank arm?

    I understand the flywheel effect on a car but unlike a car we have only 1/4 to 1/2HP available to us (the 1/2hp is someone like Lance Armstrong). So adding any rotating mass is bad. It isn't like adding a pound of weights to a flywheel which in a car will weight about 12lbs for a good 150HP engine, reducing it to 9lbs makes the car much easier to stall.

    So in the flywheel analogy we are talking grams of difference for our cranks but I would wager that the crank arms are more than a few grams more than a straight pair of cranks. If the flywheel effect was such a boon why not put that mass in the chainring instead, as we all know that the further the mass gets from its rotation point the more momentum it will have and the greater the flywheel effect will be.

    I think the reason you are so fast, and you alluded to this in another post, is that you are using road bike gearing on your mountain bike. A big gear like that will allow you to stay on top of your gear much more on the road than a comparable 44t max on a standard mountain bike. The real proof of the pudding would be if you were faster and used less calories to ride the bike with comparable gearing. You really can't compare apples to kiwis and say that kiwis are better because they are fuzzy.
    Try this: HTFU

  83. #83
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    5,123
    Quote Originally Posted by rockcrusher View Post
    You really can't compare apples to kiwis and say that kiwis are better because they are fuzzy.
    Your argument really falls apart when you realize this is a true statement. Kiwis are better because they're fuzzy, everyone knows that!
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  84. #84
    mtbr member
    Reputation:
    Join Date
    Nov 2010
    Posts
    3,089
    Quote Originally Posted by Dad Man Walking View Post
    I think that if you put these cranks on a bike that was running Sheldon Brown's POWerWheels the damn thing would coast uphill.

    I'm in.
    The problem then is there's too much energy in the mix for the wheels to hold together without SYMMETRISPOKES and red Loctite.
    It's just not safe for most riders.

  85. #85
    Huckin' trails
    Reputation: David C's Avatar
    Join Date
    May 2011
    Posts
    5,848
    Quote Originally Posted by drew and not u View Post
    This thread:
    Winner
    Quote Originally Posted by NicoleB28 View Post
    topless. that's what all mtb girls do. we go ride, get topless, have pillow fights in the woods, scissor, then ride home!

  86. #86
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    10

    I barely ever post

    But this got me laughing hysterically at work, i would be happy to test one of these cranks on my 1997 Magna dual shock mountain bike just to prove SGT MARSH correct, lol.

  87. #87
    Tool
    Reputation: Pedalphile's Avatar
    Join Date
    Aug 2008
    Posts
    1,973
    Quote Originally Posted by TheDrew View Post
    But this got me laughing hysterically at work, i would be happy to test one of these cranks on my 1997 Magna dual shock mountain bike just to prove SGT MARSH correct, lol.
    Sportin' a mullet while pimpin' this setup would add significantly more cowbell to the mix.
    I can barely get my mouth around it.

  88. #88
    meow meow
    Reputation: b-kul's Avatar
    Join Date
    Sep 2009
    Posts
    10,622
    Quote Originally Posted by drew and not u View Post
    Hey look, I can make charts and graphs and feel professional too!

    This thread:
    most epic post in a while? i think yes!

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •