• Mike hall used dynamo on his tour divide record.

  • He didn't use dynamo on his trans am record.

What would be the differentiating factor to use or not to use dynamo?

My guess is that trans am route has more service stations you can charge your batteries?

  • edit

He says he's not using dynamo in a vid, but I think he might have changed his mind before actual run..

enter image description here

If you look closely at the front hub, it is not thick.. dynamo hub seems to be thicker.. (http://bikepacker.com/mike-hall/)

enter image description here

  • 1
    Was one event supported, (even a little) and one completely unsupported ? Could have also been time-of-year related, one done in midsummer with long days and short nights such that lights were less required.
    – Criggie
    Dec 14, 2020 at 8:17
  • they are both unsupported . I believe TD starts at july, Trans AM starts at june. TD starts from canada border (more north)
    – eugene
    Dec 14, 2020 at 8:27
  • 1
    @Criggie TD was more remote - less chance of repair but less chance of charging. Also rougher terrain for which dynamo lights are IME marginal - but there are ways round that like using the dynamo to charge high-power lights.
    – Chris H
    Dec 14, 2020 at 13:50
  • @eugene what's your source for those 2 statements? I have some thoughts that may lead to an answer, but it would be easier starting with what you already know
    – Chris H
    Dec 14, 2020 at 13:51
  • Mike Hall discusses his equipment for a round-the-world ride in this article. He eschewed a dyno hub for that. He does discuss his lighting, electrics, and night-riding schedule. Not sure if it's the same setup he used in the TABR.
    – Adam Rice
    Dec 14, 2020 at 18:03

1 Answer 1

  • In 2014, Mike Hall finished the TABR ~20 hours ahead of the second-place finisher.
  • Dynamo hubs impose a drag of 1–6 W when they're disengaged, and 1–25 W when engaged. There's a fair amount of variation between hubs, and in the loads that different headlights impose on them, and the loads vary with speed.
  • Ride Far has an analysis of how much time dyno hubs would be engaged in a bikepacking race and how much net loss they'd impose. This analysis is in terms of the TCR, not TABR, but even allowing for that difference, it seems that a dyno hub would add 2 hours or less to Mike Hall's time.
  • There are a lot of unknowns here. Did Mike Hall waste any time charging lights or other electronics when he would have been riding otherwise? Can we compare his performance in 2014 to performances in other years?

I think it's fair to say Mike Hall would have won TABR 2014 with an impressive time even with a dyno setup, and I'm surprised to learn he didn't use one.

The problem with relying on public facilities to recharge your electronics is that charging is slow, even if facilities are guaranteed to be available exactly when you need them. Headlights that might only deliver one night's worth of useful light (or less) can take 5 hours to charge (I'm looking specifically at the B&M Ixon Space). Even high-capacity power banks with modern fast-charging capabilities (which didn't exist in 2014) can take 4 hours to fully charge, but could be used to recharge a headlight several times.

  • 2
    25W when engaged? With very few, mostly historic, exceptions the output is more like 3W into directly powered lights and they're far more than the 12% efficient that implies. The only way you'll get more than about 10W drag out of a dynamo hub is by using a device that allows charging while fully operating lights - which Mike Hall may have done, but only with good reason (I can only charge things from my dynamo with my lights off, and that slowly)
    – Chris H
    Dec 14, 2020 at 16:11
  • 1
    You can click through the "dynamo hubs" link and see it documented—if you disagree, take it up with "Skjegg," who did the testing. I agree 25 W is a worst-case scenario, but that's why I put it as the upper end of a range.
    – Adam Rice
    Dec 14, 2020 at 16:17
  • It's very much a worst case, one that I'd call an outlier, but fair enough. That's with a light that's designed to suck as much power as possible from the dynamo (as I suspected in my previous comment), coincidentally with the hub I have on my tourer
    – Chris H
    Dec 14, 2020 at 16:30
  • Mike hall said his light is running 32hours. and he's carrying two of them. if he used 6 hours a day, he could be running 10 days without charging
    – eugene
    Dec 15, 2020 at 4:47

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