I think the video link is in MickF's marathon 'triple shifting' thread.
BTW I do think the square taper system is a bit flexy (see post #2 in this thread... have we come far yet??).
The BB axle is near enough the same diameter as steel that is used to make coil springs in road vehicles.... it does bend.... but I do not think this is a major problem for most riders, mostly it is big chaps/racing that brings this out, but there are bound to be others....
cheers
What's wrong with square taper cranks?
Re: What's wrong with square taper cranks?
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: What's wrong with square taper cranks?
I don't think it's all that difficult to make good quality ST BBs, or anything wrong with the basic technology.
That it's possible to get failures is true of most technologies, particularly when a wide variety of qualities are available and a huge range of fitting ability is allowed for - especially when there are two similar but incompatible standards for the taper!
The amount of flex is not going to be much different with a change in the crank mounting method, since a large portion of it seems to be the frame anyway, and the bearing mounting and crank mounting aren't inextricably linked in any case.
The problems seem to mostly be down to over-lightening on high end stuff, poor precision or materials on low end stuff, or quality of installation.
The alternatives seem to be mostly about companies trying to avoid infringing each other's patents, shaving a couple of grammes off the weight or pence off the production cost, while trying to capture the market for themselves (i.e. deliberately make stuff that's incompatible with alternative parts from the competition, and gives them a patentable difference to stop anyone making pattern parts).
So IMO, ST is fine as long as you avoid the extremes - too cheap is likely to be poor materials and/or low precision, while stupid light has other strength problems - fit it properly, with the right tools, and check it (just to be sure).
And if it did need a change for the sake of stiffness, it wouldn't have been at the BB/crank interface anyway - moving the bearings outboard a little does not require that to be changed (but if they'd done that, they couldn't tie users to {$manufacturer brand} for the other parts.
Once they've got us tied into branded BBs with proprietary crank interfaces, how long before the pedal spindle gets the same treatment, and you stop being able to choose your own pedals? Then of course there's the cleats, and the shoes.
Going back the other way, will one of the manufacturers foist a different chainring fitment then chain pitch on us?
I know Shimano tried once, but that was optional - wait until they can produce cranksets that are the only way of interfacing their proprietary BBs and pedals with the back wheel, and are only available in 10mm pitch
All they need do is find some minor alteration in the chain or spider/chainring interface that they can patent, and you won't be able to choose any other brand of chain any more either - or rear cassette, hub, derailer. . .
That it's possible to get failures is true of most technologies, particularly when a wide variety of qualities are available and a huge range of fitting ability is allowed for - especially when there are two similar but incompatible standards for the taper!
The amount of flex is not going to be much different with a change in the crank mounting method, since a large portion of it seems to be the frame anyway, and the bearing mounting and crank mounting aren't inextricably linked in any case.
The problems seem to mostly be down to over-lightening on high end stuff, poor precision or materials on low end stuff, or quality of installation.
The alternatives seem to be mostly about companies trying to avoid infringing each other's patents, shaving a couple of grammes off the weight or pence off the production cost, while trying to capture the market for themselves (i.e. deliberately make stuff that's incompatible with alternative parts from the competition, and gives them a patentable difference to stop anyone making pattern parts).
So IMO, ST is fine as long as you avoid the extremes - too cheap is likely to be poor materials and/or low precision, while stupid light has other strength problems - fit it properly, with the right tools, and check it (just to be sure).
And if it did need a change for the sake of stiffness, it wouldn't have been at the BB/crank interface anyway - moving the bearings outboard a little does not require that to be changed (but if they'd done that, they couldn't tie users to {$manufacturer brand} for the other parts.
Once they've got us tied into branded BBs with proprietary crank interfaces, how long before the pedal spindle gets the same treatment, and you stop being able to choose your own pedals? Then of course there's the cleats, and the shoes.
Going back the other way, will one of the manufacturers foist a different chainring fitment then chain pitch on us?
I know Shimano tried once, but that was optional - wait until they can produce cranksets that are the only way of interfacing their proprietary BBs and pedals with the back wheel, and are only available in 10mm pitch
All they need do is find some minor alteration in the chain or spider/chainring interface that they can patent, and you won't be able to choose any other brand of chain any more either - or rear cassette, hub, derailer. . .
Re: What's wrong with square taper cranks?
frank9755 wrote:......... I had thought the stiffness thing was rubbish until I saw Mick's video. I've not seen any videos of external bearing chainsets to see how much they flex, but Mick's one shouted out to me that there was something in it.
Mick F wrote:Ditto.
I thought all this guff about stiffness was rubbish too!
I'm glad I videoed it and I'm glad that people can see.
Thank you for watching!
niggle wrote:Where is this video? I would really like to see it.
http://www.youtube.com/watch?v=vKZI85mg ... ature=plcp
http://www.youtube.com/watch?v=h7LlTCAK ... ature=plcp
Mick F. Cornwall