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  1. #11
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    Its interesting how the wireless element of the eTap is the thing that seems to appeal to a lot of e-waverers... Shimano better be going back to the drawing board with Di2!
    "Training is also a battle" - Kim Jong-Un

  2. #12
    Senior Member coolboarder's Avatar
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    Quote Originally Posted by Lataxe View Post
    I arranged the cogs to start with a proper top gear - 14-15-16-17-18-19-20-21-25-28-32.
    Presumably you have cannibalised cassettes or bought individual sprockets then?

    PS to this just found this multi-choice Miche cassette so eat my words.


    Quote Originally Posted by Lataxe View Post
    There are endless web pages devoted to the theory and test results of modern bicycle tyre design and the reasons/evidence showing that wider with less pressure is, up to a certain point, more efficient than narrower with more pressure, all other tings being equal.
    The key phrase is 'up to a certain point'. Narrow = more aerodynamic; wide = larger air pocket so can be run at lower pressure which in turn = lower rolling resistance and hysteresis loss with the bonus of being more comfortable. The fit of the tyre to the rim is also aerodynamically significant and some slightly wider tyres on a wider rim can be more aerodynamic that a narrower tyre that is not matched to the rim. Go too wide however and lower the pressure too much and increased friction comes into play as well. Add into the equation that us racing snakes can run a 23 mm tyre at 80-90 psi without fear of pinch flats whereas lard arses need more pressure and there is a huge melting pot of compromise and no one-size-fits-all.

    As said, I cannot foresee a situation where anything over 28 mm even for a heavier rider can ever be 'super efficient' even with perfectly matched tyre/rim aero combinations. But we are talking about racing/riding fast here, not pottering around at 12 mph on a touring bike laden with luggage.
    Last edited by coolboarder; 30th December 2016 at 1:45 PM. Reason: additional text
    It doesn't matter how many times you fall down, its how times many you get back up that count.

  3. #13
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    Quote Originally Posted by Gasper View Post
    I am not an "early adopter" of the latest technology, I like to let others test it first and iron out the niggles for a few years. Then prices fall, and I may buy in if other people like it in the real world. So with wireless gear changing, the latest versions may be lighter, cheaper and more reliable and finally worth trying.
    Gasper, old caution,

    That is a wise attitood. Although I too tend to put off the decision-making for ever-so-long (in the hope that the "need" for it goes away) I did fall for the current disc brake price scam. Putting these on the winter Domane cost nearly 400, what with the new STI levers, callipers, 11-speed cassettes and rear changer (no 9-speed STI Hydro levers available). If one looks at MTB equivalents they are tens rather than hundreds of pounds. A swizz, I tellee!

    Lataxe, a sucker not given an even break, even by Rose (least expensive for the aforementioned bits, even after the Brexit pound-plunge).

  4. #14
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    Quote Originally Posted by PRSboy View Post
    Its interesting how the wireless element of the eTap is the thing that seems to appeal to a lot of e-waverers... Shimano better be going back to the drawing board with Di2!
    Yes, that's a large part of the appeal. The other attraction is the small and swappable batteries that can also be sensibly carried as a spare in the tool-bottle.

    Personally I don't want internal wires or cables as they seem to cause endless routing and noise problems, yet many modern frames insist on these infernal internals because "it looks neater". I am not the neat fetishist myself; and prefer functionality to looks, if there's a contention atween the two.

    I am wary of being hostage to the fortune of the electronics, though. I've never had a problem fixing an errant mechanical gear out on the road (not that they become errant too often). The electronics are in a black box, though. ..... I suppose that they may nevertheless be reliable and, if so, I'll eventually fall for them.

    Lataxe, digging about for ebay fodder to reduce the bill.

  5. #15
    Senior Member coolboarder's Avatar
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    Quote Originally Posted by PRSboy View Post
    Its interesting how the wireless element of the eTap is the thing that seems to appeal to a lot of e-waverers... Shimano better be going back to the drawing board with Di2!
    I wonder how they will react when it comes to FSA's new hybrid electronic system: half and half wired/wireless with one external battery mounted on the front mech.

    When I was buying my new bike I started with Di2 on a De Rosa which I didn't like and was much happier when that went back and I got the Supersix with mechanical Dura Ace.
    It doesn't matter how many times you fall down, its how times many you get back up that count.

  6. #16
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    Quote Originally Posted by coolboarder View Post
    Presumably you have cannibalised cassettes or bought individual sprockets then?

    PS to this just found this multi-choice Miche cassette so eat my words.
    I did buy two cassettes (as I often have to, to get the ratios I want) then disembowelled them to reassemble into one I do want and one I don't. It annoys me no end that I have to do this because Shimano are too thick to realise that not everyone wants an 11,12 or even 13 smallest sprocket, even if the advertman has convinced them they need one so they can be Wiggo or Cav. Shimano sell an 11-32 and a 14-28. This is daft, as they should be 14-32 and 11-28 (although 13-28 would be much more useful to everyone except those who can output 400 watts for half an hour).

    Quote Originally Posted by coolboarder View Post
    The key phrase is 'up to a certain point'. Narrow = more aerodynamic; wide = larger air pocket so can be run at lower pressure which in turn = lower rolling resistance and hysteresis loss with the bonus of being more comfortable. The fit of the tyre to the rim is also aerodynamically significant and some slightly wider tyres on a wider rim can be more aerodynamic that a narrower tyre that is not matched to the rim. Go too wide however and lower the pressure too much and increased friction comes into play as well. Add into the equation that us racing snakes can run a 23 mm tyre at 80-90 psi without fear of pinch flats whereas lard arses need more pressure and there is a huge melting pot of compromise and no one-size-fits-all.

    As said, I cannot foresee a situation where anything over 28 mm even for a heavier rider can ever be 'super efficient' even with perfectly matched tyre/rim aero combinations. But we are talking about racing/riding fast here, not pottering around at 12 mph on a touring bike laden with luggage.
    Aerodynamics is about laminar air flow over surfaces, not so much about mere frontal area. As you mention, a well-designed pairing of wider tyres and rims can be more aerodynamic than a less-well designed skinny rim and tyre.

    It would be interesting to see empirical data concerning various rim & tyre combinations inclusive of both wide & narrow but also having the many permutations of other elements such as rim-tyre integration, carcass thread-count and even those small sipes which are said to improve air-flow over the tyre in some cases. I suspect that even a 32mm tyre that's integrated with the rim and has all the low rolling resistance features would perform very well at the right pressure for rider+bike weight.

    Let's not forget, either, that tyres are not just for going fast but also going safely - which can sometimes mean faster too. For example, on 28mm Schwalbe Ones, that are actually 29.5mm wide on the nice HED Ardennes wheels, blown up to a mere 75-80psi, I can go down many steep-bendy descents at a rate far in excess of that I used to feel safe at on my old racing bike. Those low-pressure bigger-contact-patch and sticky tyres allow remarkable degrees of banking-over before there's any sign of slippage. The compliant bike frame helps a bit too (keeps the tyres in contact with the road) but it is mostly the tyres.

    And low pressure reduces punctures - or so I surmise having had none for years now, compared to several a year on the 21mm 110-120 psi rock 'ard tyres of my racing years.

    Lataxe

  7. #17
    Senior Member Lee C's Avatar
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    Re wireless I'm reminded of the Tinkoff mechanic being asked why all the team had it on there bikes except team leader Contador who you'd expect to have the best.

    His answer "reliability"

  8. #18
    Senior Member coolboarder's Avatar
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    Quote Originally Posted by Lataxe View Post
    And low pressure reduces punctures - or so I surmise having had none for years now, compared to several a year on the 21mm 110-120 psi rock 'ard tyres of my racing years.

    Lataxe
    I suspect this very much more to do with quality of the tyre carcass than pressure. One can imagine the softer tyre deforming around a sharp object and thus there being less pressure to drive it through the tread but I suspect that is too marginal to make a difference. I've never suffered many punctures but then maybe that is because being a 9.5 stone weakling I always ran my tyres much softer.
    It doesn't matter how many times you fall down, its how times many you get back up that count.

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