Weird cranks on Ebay
Mike400
Posts: 226
Noticed these when I was browsing cranksets:
http://cgi.ebay.co.uk/NO-UPPER-DEAD-POI ... 3eff7e0ea8
Never seen anything like them before!
http://cgi.ebay.co.uk/NO-UPPER-DEAD-POI ... 3eff7e0ea8
Never seen anything like them before!
twitter @fat_cyclist
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Comments
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Look like an updated version of the PMP cranks:
http://www.classicrendezvous.com/Italy/PMP_main.htm
I'm not sure whether they are cool or not. I think I like them though.0 -
apparently you have to lubricate them with snake oil.0 -
UndercoverElephant wrote:Look like an updated version of the PMP cranks:
http://www.classicrendezvous.com/Italy/PMP_main.htm
I'm not sure whether they are cool or not. I think I like them though.
Cheers for that, interesting stuff. Must be a reason they were consigned to history though.will3 wrote:
apparently you have to lubricate them with snake oil.
My initial thoughts, but when you actually think about it the theory makes sense. Whether they are any good in the real world is anyones guess.
The cynic in me would look to the UCI regs to see if that killed them off?twitter @fat_cyclist0 -
I'm not sure about the spiral ones, but I believe the thing that killed off the L-shaped ones was the fact they had to be longer and thus actually had more flex; allied to the fact that the PMP ones bent the wrong way to have their alleged improvement.
I think it was more the lack of available horse-feather grease fr the installation which killed them off.0 -
I think they'd only work if the curved (or right-angled) bit was quite heavy so its momentum propelled the foot through the dead-spots... If that were the case they'd take a bit more effort to spin up.
Effective or not, it's a good way to raise your bike above the UCI weight limit :P0 -
Mike400 wrote:
My initial thoughts, but when you actually think about it the theory makes sense. Whether they are any good in the real world is anyones guess.
?
Or thjnk about it for a microsecond and realise it's very clearly bollox.0 -
I don't really see how they can make a different. I mean, the pedal spindle is still in line with the spindle of the other pedal, on a line going through the centre of the bottom bracket. It just seems to be exactly the same mechanism as a straight crank to me.0
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JonGinge wrote:I think they'd only work if the curved (or right-angled) bit was quite heavy so its momentum propelled the foot through the dead-spots... If that were the case they'd take a bit more effort to spin up.
:P
That effect would be cancelled out exactly by the other crank.
It doesn't matter what fancy route you take between the pedal and the chainwheel, the relative positions remain the same.0 -
will3 wrote:JonGinge wrote:I think they'd only work if the curved (or right-angled) bit was quite heavy so its momentum propelled the foot through the dead-spots... If that were the case they'd take a bit more effort to spin up.
:P
That effect would be cancelled out exactly by the other crank.
It doesn't matter what fancy route you take between the pedal and the chainwheel, the relative positions remain the same.
This was pure hypothesis to try to explain why someone would design such a monstosity not because I believe it. I really don't think they would work either.0 -
JonGinge wrote:
That effect would be cancelled out exactly by the other crank.
It doesn't matter what fancy route you take between the pedal and the chainwheel, the relative positions remain the same.
Which you could achieve just by making really heavy cranks. Can't see a downside to that can you oh wait , you did see a downside.........JonGinge wrote:This was pure hypothesis to try to explain why someone would design such a monstosity not because I believe it. I really don't think they would work either.
you will go far0 -
Mike400 wrote:My initial thoughts, but when you actually think about it the theory makes sense. Whether they are any good in the real world is anyones guess.
The cynic in me would look to the UCI regs to see if that killed them off?
Meh.
Thought experiment; Consider how the position of the pedal axles move in relation to the bottom bracket.0