J
jim beam
Guest
Tom Kunich wrote:
> "Simon Brooke" <[email protected]> wrote in message
> news:[email protected]...
>> in message <[email protected]>, Tom
>> Kunich ('cyclintom@yahoo. com') wrote:
>>
>>>
>>> Simon, it is apparent that you have some education in mechanical design.
>>> This whole argument began when I said that there wasn't anything to GAIN
>>> by going to electronic shifting. It's only another failure point in an
>>> otherwise highly reliable machine. But jim beam (named apparently from
>>> what he is under the influence of ) seems to believe that derailleurs
>>> which are almost the perfect mechanism, can be markedly improved with
>>> electronics.
>>
>> OK, I hear what you're saying and I'm not sure I agree. It's partly
>> because
>> I'm a geek and like playing with toys. But also, one of my bikes - the
>> one
>> I ride to work most days - is an old steel Raleigh. It suffers from frame
>> flex. And one of the problems that frame flex causes is that because the
>> parallelogram is attached to the back of the frame, and controlled by a
>> bit of wire that is under tension from the front of the frame, as the
>> front of the frame and the back of the frame move relative to one another
>> you get ghost shifts. This is exacerbated on my Raleigh, of course, by
>> the
>> fact that it was designed for a five speed freewheel and now has a nine
>> speed cassette, so smaller distortions of the frame cause ghostshifts
>> than
>> would have been the case when it was new...
>
> Try this Simon - carefully grease the shift cables where they make the
> turn at the bottom bracket and I'm reasonably sure that your ghost
> shifts will disappear. I'm 6'4" and weigh 200 lbs and I can't cause a
> bike to ghost shift when properly set up. I've had a lot of Peugeots,
> Gitanes, old Bottechias, Schwinns and a lot of garbage bikes and none of
> them would ghost shift even though the bay area has a lot of hard climbing.
>
>> With modern, closer tolerance derailleur trains the derailleur cage is
>> still attached to the back of the frame but the detents which control its
>> position are in the shifter mechanism at the front of the frame (or,
>> actually, on the handlebar...).
>
> I can't imagine someone flexing a C50. The C40 is so stiff that you can
> feel a distinct difference in handling going through rough 40 mph
> downhill esses.
>
>> The detents really ought to be in the derailleur mechanism itself.
>
> That's a point of argument. Shimano started out that way and it didn't
> work well.
>
>> [As an aside a pantograph is not really the ideal mechanism for something
>> that wants to track across a cassette at a fixed distance from the cogs -
>> particularly on a machine on which different sized cassettes may be used.
>> The optimum trajectory for a 12-21 cassette is quite different from that
>> for a 13-26 cassette. Mind you, I'm not saying I could design a better]
>
> We don't care about ideal. We care about workable and the slant
> parallelogram is the best working mechanism to date.
>
>> If the detents are going to be in the derailleur mechanism, then an
>> electronically triggered movement is quite a good idea. I can imagine a
>> mechanical system where a short tug on the cable released the mechanism
>> one detent, and a longer tug on the cable lifted the mechanism one
>> detent,
>> with a user interface much like the SRAM 'double tap' (the cable being
>> slack between actuations). But an advantage of electronic actuation, as
>> Mektronic demonstrated, is you can have multiple switch positions so that
>> it becomes easy to change gear from the tops as well as the hoods and the
>> drops. And if you have electronic actuation, then taking the energy to
>> lift the mechanism from the chain seems to me clever and cool.
>
> The bottom line is this - todays races could be just as easily won with
> friction shifting 7 speed barend shifters as STI. The complex mechanisms
> being used are not improvements - they are marketing devices.
>
>> Also, it's easy to build an electrical wiring harness into a carbon
>> composite structure. Thus exposed cables could be a thing of the past,
>> and
>> I'd see that as a positive thing.
>
> That's a personal choice on your part. I don't see anything in it at all.
>
>>> Well, not quite but I agree that you don't need a lot of power if you're
>>> willing to rob most of it from the drive train. But then you're either
>>> stuck with the Mektronic mechanism which has fixed stops or complex
>>> sensors and micro-adjustable position sensors which in the end would be
>>> quite a pain in the neck without adding anything to reliability,
>>> reducing
>>> costs or weight.
>>
>> I certainly think that if you're going to have electronic gear
>> actuation on
>> a racing bike in a sporting context then the energy used to lift the
>> mechanism ought to come from the competitor's muscular effort in near
>> real
>> time - if you're using stored power from a battery charged before the
>> event that ought to be seen as cheating.
>
> Isn't muscle energy stored before the event? (Rolls eyes) Now your
> suggesting not just a mechanical mechanism to move everything to the
> proper position but also a generator to power the electronics. Time for
> Donnelly to explain the facts of life visa vi power.
>
>>> The modern bicycle is the end result of a hundred and fifty years of
>>> evolution. It achieved it's peak in the 1960's and everything added
>>> since
>>> then has been only for performance on smooth roads.
>>
>> I'm not at all sure I agree with that. I have two road bikes I ride
>> regularly, a modern carbon Dolan and the fifteen-year-old steel Raleigh.
>
> What difference do you see between your Raleigh and your Dolan? What
> about comparing my Basso to your Dolan?
>
gainsay is not an argument. try again.
> "Simon Brooke" <[email protected]> wrote in message
> news:[email protected]...
>> in message <[email protected]>, Tom
>> Kunich ('cyclintom@yahoo. com') wrote:
>>
>>>
>>> Simon, it is apparent that you have some education in mechanical design.
>>> This whole argument began when I said that there wasn't anything to GAIN
>>> by going to electronic shifting. It's only another failure point in an
>>> otherwise highly reliable machine. But jim beam (named apparently from
>>> what he is under the influence of ) seems to believe that derailleurs
>>> which are almost the perfect mechanism, can be markedly improved with
>>> electronics.
>>
>> OK, I hear what you're saying and I'm not sure I agree. It's partly
>> because
>> I'm a geek and like playing with toys. But also, one of my bikes - the
>> one
>> I ride to work most days - is an old steel Raleigh. It suffers from frame
>> flex. And one of the problems that frame flex causes is that because the
>> parallelogram is attached to the back of the frame, and controlled by a
>> bit of wire that is under tension from the front of the frame, as the
>> front of the frame and the back of the frame move relative to one another
>> you get ghost shifts. This is exacerbated on my Raleigh, of course, by
>> the
>> fact that it was designed for a five speed freewheel and now has a nine
>> speed cassette, so smaller distortions of the frame cause ghostshifts
>> than
>> would have been the case when it was new...
>
> Try this Simon - carefully grease the shift cables where they make the
> turn at the bottom bracket and I'm reasonably sure that your ghost
> shifts will disappear. I'm 6'4" and weigh 200 lbs and I can't cause a
> bike to ghost shift when properly set up. I've had a lot of Peugeots,
> Gitanes, old Bottechias, Schwinns and a lot of garbage bikes and none of
> them would ghost shift even though the bay area has a lot of hard climbing.
>
>> With modern, closer tolerance derailleur trains the derailleur cage is
>> still attached to the back of the frame but the detents which control its
>> position are in the shifter mechanism at the front of the frame (or,
>> actually, on the handlebar...).
>
> I can't imagine someone flexing a C50. The C40 is so stiff that you can
> feel a distinct difference in handling going through rough 40 mph
> downhill esses.
>
>> The detents really ought to be in the derailleur mechanism itself.
>
> That's a point of argument. Shimano started out that way and it didn't
> work well.
>
>> [As an aside a pantograph is not really the ideal mechanism for something
>> that wants to track across a cassette at a fixed distance from the cogs -
>> particularly on a machine on which different sized cassettes may be used.
>> The optimum trajectory for a 12-21 cassette is quite different from that
>> for a 13-26 cassette. Mind you, I'm not saying I could design a better]
>
> We don't care about ideal. We care about workable and the slant
> parallelogram is the best working mechanism to date.
>
>> If the detents are going to be in the derailleur mechanism, then an
>> electronically triggered movement is quite a good idea. I can imagine a
>> mechanical system where a short tug on the cable released the mechanism
>> one detent, and a longer tug on the cable lifted the mechanism one
>> detent,
>> with a user interface much like the SRAM 'double tap' (the cable being
>> slack between actuations). But an advantage of electronic actuation, as
>> Mektronic demonstrated, is you can have multiple switch positions so that
>> it becomes easy to change gear from the tops as well as the hoods and the
>> drops. And if you have electronic actuation, then taking the energy to
>> lift the mechanism from the chain seems to me clever and cool.
>
> The bottom line is this - todays races could be just as easily won with
> friction shifting 7 speed barend shifters as STI. The complex mechanisms
> being used are not improvements - they are marketing devices.
>
>> Also, it's easy to build an electrical wiring harness into a carbon
>> composite structure. Thus exposed cables could be a thing of the past,
>> and
>> I'd see that as a positive thing.
>
> That's a personal choice on your part. I don't see anything in it at all.
>
>>> Well, not quite but I agree that you don't need a lot of power if you're
>>> willing to rob most of it from the drive train. But then you're either
>>> stuck with the Mektronic mechanism which has fixed stops or complex
>>> sensors and micro-adjustable position sensors which in the end would be
>>> quite a pain in the neck without adding anything to reliability,
>>> reducing
>>> costs or weight.
>>
>> I certainly think that if you're going to have electronic gear
>> actuation on
>> a racing bike in a sporting context then the energy used to lift the
>> mechanism ought to come from the competitor's muscular effort in near
>> real
>> time - if you're using stored power from a battery charged before the
>> event that ought to be seen as cheating.
>
> Isn't muscle energy stored before the event? (Rolls eyes) Now your
> suggesting not just a mechanical mechanism to move everything to the
> proper position but also a generator to power the electronics. Time for
> Donnelly to explain the facts of life visa vi power.
>
>>> The modern bicycle is the end result of a hundred and fifty years of
>>> evolution. It achieved it's peak in the 1960's and everything added
>>> since
>>> then has been only for performance on smooth roads.
>>
>> I'm not at all sure I agree with that. I have two road bikes I ride
>> regularly, a modern carbon Dolan and the fifteen-year-old steel Raleigh.
>
> What difference do you see between your Raleigh and your Dolan? What
> about comparing my Basso to your Dolan?
>
gainsay is not an argument. try again.
