See you, Jimmy

It was an exciting weekend for my bike as it returned to its ancestral home, Glasgow, albeit just for one day. The occasion was the Cycling Embassy’s infrastructure tour, which I won’t bore you with here (I’ll bore you with it elsewhere, don’t worry). Getting there on the train means a 40 minute ride to the station for the once-every-three hours, two-hour long chuffer service (it’s all of 75-odd miles, but never mind that – look at the lovely scenery!). Thus my Saturday started with me waking in the dark and listening to the rain splattering energetically against the window and wondering why I hadn’t taken up knitting advocacy or something equally indoorsy.

Fortunately, a glitch in the Weather Gods’ system meant I managed to ride to the station during the 40 minute break in the rain and was safely under the canopy discovering I’d forgotten my bike lock when the heavens opened again. And amazingly, despite a forecast bordering on the apocalyptic, another 15 or so hardy souls turned up for the event and even though we did get snowed on a little and were visited by the puncture fairy and I discovered that my back brake wasn’t working (I don’t really need to stop the bike much around here, so it doesn’t really arise. Oops), it was an interesting (adjusted for being mainly about cycle infrastructure) day out all round.

Heading back, after an after tour tour of the pubs of Glasgow looking for one that wasn’t absolutely rammed on a Saturday night – a mission akin to trying to find a decent piece of cycling provision in the average UK city – I got on a train that turned out to be full of Rangers fans (do they know that peace has more or less broken out in Northern Ireland, btw? Do you think maybe someone should tell them?) and reached Bigtown at 9pm ready for the 8 miles back – the first time I got to try out my dynamo lighting for real.

So what’s the verdict? Well the first thing is that, if anyone tells you they ‘hardly feel’ the effect of a dynamo on a bike, then they’re either lying or have legs of steel. The second is that it lights up the road like nobody’s business, possibly even better than the light I borrowed last year. The third is that a pint of Newcastle Brown Ale and a bag of chips are not, perhaps, the ideal pre-ride meal for someone who wants to test out their dynamo for the first time, although I’m not sure exactly would have been – maybe spinach?

I woke up on Sunday morning with leaden legs, feeling absolutely shattered. And then the sun came out and as we were out of milk, we did the run again in the afternoon down to the local garage and I remembered that the road back from Bigtown always feels like extra hard work, seeing as it’s uphill and into a headwind.

I reckon on balance, the dynamo adds about an extra 10 mph to the wind in your face, although it does seem to feel like harder work the slower you go; struggling up the final bit of hill at the end of a long ride was just cruel. On the plus side, the way it lights up the road means you can get up to speed on the downhill bits and take a run at the next climb. For people whose brakes have gone a bit kaput, it’s reassuring to know you’ll be able to see what’s up ahead in good time. If I were commuting home in the dark five days a week I’d probably lay out the cash to get a rechargeable system, just because I think it would be pretty wearing every day and I don’t really want to end up with the legs of Chris Hoy. But for the use I want to put it to – the occasional trip into town of an evening, and back and forth to the village, it will be fine. More than fine, in fact, if the night is as black and as starry and sparkly as Saturday was.

And now, I think it might be time to get that bike down to the bike shop for a bit of love and attention to those brakes…

16 Responses to See you, Jimmy

  1. Hub dynamos really do have imperceptible drag, the bottle is noticeable but negligible only if it is set up so that it uses the minimum pressure on the tyre needed to prevent slippage. The other thing I found about the Nordlicht is that, being designed to produce full output at very low speeds, with the standard roller it produces more drag than is ideal at the sorts of speeds people tend to ride when they have to share the road with fast motor vehicles. David Hembrow (other bike shops are available) sells the larger roller which effectively gears the whole thing down. It still produces full output at a little over walking speed and reduces drag quite a lot too.

  2. disgruntled says:

    I may have to have a play with the pressure / rollers then. It was noticeably hard work at slow speeds, as if it was somehow easier once it had ‘got going’. I wouldn’t want to cut the output much though – being able to see well ahead of the bike was the best bit

    • It’s probably worth it. I use one on the Yuba and before the bigger roller it had full output at about 4 km/h, with the new roller I get full output at about 7 km/h, still pretty damn but significantly reduced drag. The increased size means less wear on the roller too, and it seems to slip less at a higher speeds for a given pressure. It took a bit of fettling before I got the Nordlicht to my satisfaction on the Yuba, but now it is I just leave it on all the time.

  3. The Paper Boy says:

    I remember as a kid putting a couple of O-rings on my bottle dynamo – increased the circumference by about 15-20% of the rotor which shouldn’t be a problem and it’s instantly reversible if it is a problem…

  4. Kim says:

    If anyone tells you they ‘hardly feel’ the effect of a dynamo on a bike, they have hub dynamo which is considerably more efficient than a bottle dynamo. Did you notice the hub dynamo on the Paper Bicycle you rode in Edinburgh… 😉

  5. disgruntled says:

    Paper boy – that might be worth a shot
    Kim – yep, I’m getting that impression via twitter. Or they’ve all got legs of steel…

  6. Hi Sally, if you really feel it in your legs when the dynamo is on then you need to look at the setup. Not only will it be wearing you out, but perhaps also wearing out the roller or even the bearings in the dynamo if it’s misaligned (this won’t happen instantly so you won’t have damaged it already). The amount of pressure against the side of the tyre should be as little as possible without leading to slipping and the dynamo must be lined up such that its axis extends through the centre of the wheel (i.e. running perpendicular to the tyre).

    There’s was a very good test of dynamos by Chris Juden a few years back (online here). It shows the amount of drag actually created by a wide range of dynamos. Not one of those tested had as much effect on the rider as a 1:300 hill and there was “quite a cluster of sidewall and hub-driven models around the 1/500 line”.

    I’ve had both hub and bottle dynamos, and the difference between them is one of those swings and roundabouts issues. Hubs are usually a little more efficient at night time when the lights are on, but they’re also heavier, more annoying to retrofit, and less efficient in the daytime when the lights are off. I do more riding in the day-time than the night-time, so I normally use bottle dynamos.

    The larger idler that chestercycling mentions does decrease the drag a little, but personally I find this difference to be nothing to write home about. I’m currently using one of the smaller idlers on my bike.

  7. Ragged Thread Cartographer says:

    On the other hand, this IS the year of the Olympics….

  8. John Gibson says:

    And now, I think it might be time to get that bike down to the bike shop for a bit of love and attention to those brakes…

    No, you need less weight, do without the brakes, you’ll be alright.
    John

  9. disgruntled says:

    David – OK, I’ll have a play with the setup.
    RTC – hmm, yes, but have you seen Chris Hoy’s thighs?
    John – maybe a combination of dynamo and no brakes cancel each other out?

  10. emma c says:

    Well this is all very interesting, I must say. I am glad you have good light to see by, despite any other failings (fixable or not) on your steed. I used to hate being blinded by a car, then seeing nothing at all after that for 10 seconds. The alternative was to shut my eyes while it passed. Your strong light must surely help that.

  11. disgruntled says:

    yup, I remember that. They do dip their headlights here at least, which helps. But so far I’ve not encountered a car with the new light

  12. The Shimano hub dynamo on my Batavus is perfectly quiet and appears to add no friction at all when the front light is on. I often find that I’ve left my front dynamo light on for days, not noticing it in the daylight.

    I suspect that the noise a dynamo makes is psychologically important – if it’s noisy it certainly sounds like it’s slowing you down. This could possibly make you push harder on the pedals but less efficiently (i.e. pushing straight down at the bottom of the stroke).

    There’s a quite different appearance of speed when cycling in the dark too, as you see things close-up reasonably well in the front light, but more distant objects are unlit. Also there’s less to look at, so you pay more attention to the effort of your legs. Possibly.

    Every now and then I try easing off my effort on the pedals, and concentrating on pushing in circles instead of up-and-down, aiming to do less work without losing any speed. Often I find I can ease off without any speed reduction, proving that I was pushing too hard!

  13. disgruntled says:

    funnily enough, I was concentrating on ‘pedalling circles’ – just to change the muscles I was using. I know what you mean about the psychological effect of the noise though.

    FWIW, I reckon it took me about 5-8 mins longer (over 8 miles) than I’d expect the trip to in daylight (and about 10-20 mins less than trying to do it with crap lights)

  14. […] other half has adjusted my dynamo, as advised in the comments, and all is now sweetness and (much) light. It got its first test last […]

  15. […] our spice rack (amazingly, it’s still organised too). In Feburary the bike got to go back to its home town  and got properly lit up. In March we got a cute new neighbour not to mention a cute new bike and […]

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