Cycling dead ends.

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mattsccm
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Cycling dead ends.

Postby mattsccm » 8 Aug 2019, 7:25am

I like the idea in another thread and thought I start this one. Lets list as many cycling technical dead ends as possible. I'll start with a couple of easy ones.
1. Biopace chainsets
2. L shaped cranks
No idea how to add pics. tried to copy and paste . Duh

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pjclinch
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Re: Cycling dead ends.

Postby pjclinch » 8 Aug 2019, 7:53am

mattsccm wrote:I like the idea in another thread and thought I start this one. Lets list as many cycling technical dead ends as possible. I'll start with a couple of easy ones.
1. Biopace chainsets
2. L shaped cranks
No idea how to add pics. tried to copy and paste . Duh


Ooh, it's whole weeks since road.cc rolled out their L-cranks feature on to Facebook!

While Biopace may be dead oval chain rings have a core of fans who feel they make a difference, and they're still being made. Normally I'd scoff at that as any sort of proof, but since 4 time Tour de France winner and lead rider of a famously analytical pro-team thinks they help him I'm not inclined to dismiss it completely out of hand. Froome may not be an engineer, but Emma Pooley is (Cambridge engineering graduate, subsequent PhD may be in soils engineering rather than bike engineering but I think she can probably do mechanics better than most of us, certainly better than me!), and she thinks they help her...

Forward sloping top-tubes seem to be out of fashion for a long time, though with some things it could be that the Luddites of Lausanne arbitrarily banned them because that's what the UCI does.

Pete.
Often seen riding a bike around Dundee...

pwa
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Re: Cycling dead ends.

Postby pwa » 8 Aug 2019, 8:25am

I once had to "set up" biopace on a bike my wife had and it struck me then that it simply didn't work as a piece of engineering. Look at it this way: with a normal round chainring we all know the front mech cage outer plate is meant to be about 3mm above the teeth. But if that matters, and it does, you can't achieve that all the way round a biopace ring. If you get 3mm at one part of the ring you will have something very different a quarter of a turn away.

Rod Goodfellow
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Re: Cycling dead ends.

Postby Rod Goodfellow » 8 Aug 2019, 8:37am

Back in 1958 I rode my first 12hr TT on 81" fixed and a brand new Brooks Swallow saddle. After doing 243 miles and a 25 mile ride home I had a dead end for the subsequent 24hrs.

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pjclinch
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Re: Cycling dead ends.

Postby pjclinch » 8 Aug 2019, 8:39am

pwa wrote:I once had to "set up" biopace on a bike my wife had and it struck me then that it simply didn't work as a piece of engineering. Look at it this way: with a normal round chainring we all know the front mech cage outer plate is meant to be about 3mm above the teeth. But if that matters, and it does, you can't achieve that all the way round a biopace ring. If you get 3mm at one part of the ring you will have something very different a quarter of a turn away.


This sounds fair enough on a first pass... but hasn't seemed to be a barrier to Froome winning 4 multiple Grand Tours where I imagine he'll have changed gear a few times.
And at the less sharp end, If I change the middle ring on my tourer it can be at pretty much any diameter between the wee ring and the big ring and I won't need to worry about the derailleur setup. So I don't see that it matters quite as much as you seem to think.
Often seen riding a bike around Dundee...

pwa
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Re: Cycling dead ends.

Postby pwa » 8 Aug 2019, 8:50am

pjclinch wrote:
pwa wrote:I once had to "set up" biopace on a bike my wife had and it struck me then that it simply didn't work as a piece of engineering. Look at it this way: with a normal round chainring we all know the front mech cage outer plate is meant to be about 3mm above the teeth. But if that matters, and it does, you can't achieve that all the way round a biopace ring. If you get 3mm at one part of the ring you will have something very different a quarter of a turn away.


This sounds fair enough on a first pass... but hasn't seemed to be a barrier to Froome winning 4 multiple Grand Tours where I imagine he'll have changed gear a few times.
And at the less sharp end, If I change the middle ring on my tourer it can be at pretty much any diameter between the wee ring and the big ring and I won't need to worry about the derailleur setup. So I don't see that it matters quite as much as you seem to think.

I don't know if it is the electronic shifting or funny rings, but I've seen Froome get off and change his bike quite a few times due to faulty gear change. I could do without the hassle. Do you remember David Millar messing up a Tour Prolog due to the chain coming off a non-round ring?
Last edited by John1054 on 8 Aug 2019, 9:06am, edited 1 time in total.
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mig
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Re: Cycling dead ends.

Postby mig » 8 Aug 2019, 9:26am

pwa wrote:
pjclinch wrote:
pwa wrote:I once had to "set up" biopace on a bike my wife had and it struck me then that it simply didn't work as a piece of engineering. Look at it this way: with a normal round chainring we all know the front mech cage outer plate is meant to be about 3mm above the teeth. But if that matters, and it does, you can't achieve that all the way round a biopace ring. If you get 3mm at one part of the ring you will have something very different a quarter of a turn away.


This sounds fair enough on a first pass... but hasn't seemed to be a barrier to Froome winning 4 multiple Grand Tours where I imagine he'll have changed gear a few times.
And at the less sharp end, If I change the middle ring on my tourer it can be at pretty much any diameter between the wee ring and the big ring and I won't need to worry about the derailleur setup. So I don't see that it matters quite as much as you seem to think.

I don't know if it is the electronic shifting or funny rings, but I've seen Froome get off and change his bike quite a few times due to faulty gear change. I could do without the hassle. Do you remember David Millar messing up a Tour Prolog due to the chain coming off a non-round ring?


hang on.....hang on....L shaped cranks are a 'dead end'..?? whaddya mean! since when?

didn't millar have an oval ring and no FD / chain catcher?

when does froome change his bike? bottom of a climb by any chance? :wink:

pwa
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Re: Cycling dead ends.

Postby pwa » 8 Aug 2019, 9:30am

mig wrote:when does froome change his bike? bottom of a climb by any chance? :wink:

:lol: Apart from that, I have seen him get off for a bike change a few times due to gear malfunction, and have to chase to get back on. My thought at the time has always been, tell what he is using so I can make sure I don't have it on my bike. But I will admit that he would not have won one TdF riding one of my bikes.

Bmblbzzz
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Re: Cycling dead ends.

Postby Bmblbzzz » 8 Aug 2019, 9:33am

Quadruple front rings don't seem to have come back. Yet.

Samuel D
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Re: Cycling dead ends.

Postby Samuel D » 8 Aug 2019, 9:53am

Tubular tyres. Took a while, though.

pwa
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Re: Cycling dead ends.

Postby pwa » 8 Aug 2019, 9:58am

Though I love the way it looks, Moulton's space frame. Too complex to manufacture economically for a bike concept that, with small wheels, was supposed to be more practical. Complex and practical rarely coincide.

Brucey
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Re: Cycling dead ends.

Postby Brucey » 8 Aug 2019, 10:02am

pjclinch wrote:…..While Biopace may be dead oval chain rings have a core of fans who feel they make a difference, and they're still being made. Normally I'd scoff at that as any sort of proof, but since 4 time Tour de France winner and lead rider of a famously analytical pro-team thinks they help him I'm not inclined to dismiss it completely out of hand. Froome may not be an engineer, but Emma Pooley is (Cambridge engineering graduate, subsequent PhD may be in soils engineering rather than bike engineering but I think she can probably do mechanics better than most of us, certainly better than me!), and she thinks they help her...


Well, er, yes and no. Clever people are not completely immune to having odd beliefs... The jury is out on oval chainrings; if they were of some real advantage and there was really science to back this up, I suspect that the entire peloton would be on them already, despite the shifting issues. It is possible that they are 'of some advantage' in that once you get used to them it is difficult to change back to something else again.

The interesting thing is that Biopace ovality is phased completely differently from the ovality that is favoured by Froome et al. ; one decreases the gear ratio during the power stroke and the other increases it. Whatever 'advantages' oval chainrings have, they can't both be right, can they...?

I'd also note that riders having to have bike changes because their gears are not working is very common in pro racing these days; if my live TV watching is anything to go by, it is almost as common as getting a puncture in some races. Often you see the rider standing by their bike, looking at the gears with an expression of bafflement and/or disgust on their face. My suspicion is that this is often caused by some problem with the Di2 but of course finding the truth of the matter is practically impossible.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Samuel D
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Re: Cycling dead ends.

Postby Samuel D » 8 Aug 2019, 10:15am

Brucey wrote:I'd also note that riders having to have bike changes because their gears are not working is very common in pro racing these days

Yeah, the frequency of gear problems is kind of unbelievable from where I’m sitting. Recent example combined with Dutch outspokenness.

Bmblbzzz
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Re: Cycling dead ends.

Postby Bmblbzzz » 8 Aug 2019, 10:15am

Steel rims, thank goodness.

KM2
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Re: Cycling dead ends.

Postby KM2 » 8 Aug 2019, 10:30am

Aren’t biopace rings in the correct orientation for recumbents?