Legal lights?

General cycling advice ( NOT technical ! )
Albrecht
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Re: Legal lights?

Post by Albrecht »

Jdsk wrote: 30 Jul 2022, 12:36pmTypically 1 to 8 W at 30 kph when on.
I was thinking more of a "feel it or not" rather then a MecEng dissertation.

One said,
pwa wrote: 13 Jul 2022, 6:29am It says the SP hub is draggy, which accords with my experience of cycling with one. I could feel the drag and didn't like it , so I gave mine away and went back to good battery lights.
but was dated 2011. That's my experience in the past, and "quite a lot", & that goes all the way to awful SA boat anchor hubs.

It's a wonder you could have a hub with a cam in it that you could engage and disengage the magnets, say, with a thumb nut on the side. I understand they've gone to rare earth magnets these days.

Why always on?

Of course, I know they still do bottle dynamos but they're not quite as elegant.
Jdsk
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Re: Legal lights?

Post by Jdsk »

Albrecht wrote: 30 Jul 2022, 12:28pm How much resistance to riding do modern hub dynamos produce?
Albrecht wrote: 30 Jul 2022, 1:21pm
Jdsk wrote: 30 Jul 2022, 12:36pmTypically 1 to 8 W at 30 kph when on.
I was thinking more of a "feel it or not" rather then a MecEng dissertation.

One said,
pwa wrote: 13 Jul 2022, 6:29am It says the SP hub is draggy, which accords with my experience of cycling with one. I could feel the drag and didn't like it , so I gave mine away and went back to good battery lights.
but was dated 2011. That's my experience in the past, and "quite a lot", & that goes all the way to awful SA boat anchor hubs.
The power consumed by a modern hub dynamo is roughly the same as needed for a 1 in 1,000 ascent.

Jonathan
Albrecht
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Re: Legal lights?

Post by Albrecht »

Funny, it feels a lot more resistant when spinning a wheel.
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Vantage
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Re: Legal lights?

Post by Vantage »

In real-feel terms, the drag from a dyno hub is about the same as letting out 5-10 psi from your tyres or a slight breeze.
Turning the axle in your bare hands the drag is exceptional. They 'click' around rather than spin but once on the bike and rolling, you'd be be hard pushed to notice it.
Bill


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Jdsk
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Re: Legal lights?

Post by Jdsk »

Vantage wrote: 30 Jul 2022, 1:29pm In real-feel terms, the drag from a dyno hub is about the same as letting out 5-10 psi from your tyres or a slight breeze.
Turning the axle in your bare hands the drag is exceptional. They 'click' around rather than spin but once on the bike and rolling, you'd be be hard pushed to notice it.
Yes. The feel when spinning by hand is misleading, and quite worrying until you're used to it.

Jonathan
pwa
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Re: Legal lights?

Post by pwa »

I vaguely remember that Brucey, in one of his later posts, referred to a study that highlighted an extra phenomenon going on within generators that makes the inefficiency, or drag, worse than is normally stated. Does anyone remember that?

viewtopic.php?p=1568115#p1568115

I ditched my SP generator because I noticed that after freewheeling down familiar descents I was having to resume pedalling sooner than when not on that hub. If the bike behaved that way and did not have that hub on it, I'd be looking for the fault when I got home. Brake rub? A fault with a bearing?
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gazza_d
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Re: Legal lights?

Post by gazza_d »

I bought a new bike last summer and rode around on it for a few weeks before I got around to fitting an SP dynamo and some lights.

I have to say that I didn't notice any reduction in speed and if anything there is less drag from the SP than from the Shimano dynohubs in my other Moultons..

I have an auto-sensing B&M light on the front and it's great to be honest. Fit and forget and it's as bright as a cars light. I spent all winter clattering around on early morning rides often on unlit roads and paths and it's great.

Of course OP may prefer battery lights and that's fine. I would always recommend going for a light with the German standard as it focusses the beam where you need it whilst still ensuring you can be seen.

I'm firmly of the opinion that some drivers see flashing lights from a distance, and because they can safely assume it will be a cyclist, will pass closer. That was my experience before I switched to dynamos. Even as a cyclist when I'm driving I find that flashing LEDs can "disappear" amongst other lights and sometimes be hard to make out.

And don't get me started on the fallacy of daytime lights. I don't think they have any value. I've never failed to see a cyclist in the daytime without them. I just think they redraw the line in the sand further back, and potentially just push more responsibility onto the cyclist and absolve drivers from actually making an effort to look.

You just need to be seen, it doesn't actually matter as what
rogerzilla
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Re: Legal lights?

Post by rogerzilla »

The SV-9 I have has noticeably lower drag than the older SV-8 but apparently is less robust, as SP have lightened it.

The drag is just about noticeable when riding. The B&M IQ-XS headlight on my Moulton is very reluctant to turn off (B&M's high-end lights use hopeless electronic switches) and it doesn't help with speed. I've ridden the Dunwich Dynamo many times and it was always faster with battery lights. That slight drag is equivalent to a pretty big hill over 113 miles, and adds about 20 minutes to the ride time.
LancsGirl
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Re: Legal lights?

Post by LancsGirl »

Update:

So I got the Lezyne MacroDrive 1300XXL. As recommended.

It's charging now. Certainly feels substantial and well made.

Though slight disappointment, due entirely to me not researching thoroughly enough. The light doesn't shine when it is being charged, as least as far as I can tell. So using it on a ride with a battery pack charging it whilst riding wouldn't work. I'd have to stop to recharge it.

Are all USB chargeable lights like that? Have I misunderstood?

Though this will very rarely, probably never, be a problem for me. As it's got such good capacity, and if I were riding for long enough to flatten it, I'd want a break anyway. Still, I wish I'd spotted that.

If I get to a situation where it becomes an issue then that pretty much means I should be looking at a dynohub.

Cheers.
Jdsk
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Re: Legal lights?

Post by Jdsk »

LancsGirl wrote: 10 Aug 2022, 12:59pmThough slight disappointment, due entirely to me not researching thoroughly enough. The light doesn't shine when it is being charged, as least as far as I can tell. So using it on a ride with a battery pack charging it whilst riding wouldn't work. I'd have to stop to recharge it.

Are all USB chargeable lights like that? Have I misunderstood?
Thanks for the update, and looking forward to your experiences with it.

That's the question where I retracted my initial comment. It would be very helpful to know about other USB-charged lamps.

Jonathan
PH
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Re: Legal lights?

Post by PH »

LancsGirl wrote: 10 Aug 2022, 12:59pm Update:

So I got the Lezyne MacroDrive 1300XXL. As recommended.
What happened to the idea of being legal?
That light is about as antisocial as they come. If you put that on a motorbike it would fail a MOT.
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freiston
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Re: Legal lights?

Post by freiston »

I'm afraid that I agree with PH on this one - I've just seen a beam pattern photo in the CC review - it's the same as a regular torch not designed for anything other being a blinding torch that throws as much light above the horizon as it does below - and plenty into the eyes of other road users.
Image
Disclaimer: Treat what I say with caution and if possible, wait for someone with more knowledge and experience to contribute. ;)
LancsGirl
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Re: Legal lights?

Post by LancsGirl »

Oh dear. I seem to have bought the wrong thing. A bit too eager to just take that magazine review recommendation. Too late to change for now (on holiday soon). I'll reconsider when I get back. As it's new and will be in vgc I daresay I can turn it round on eBay.
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freiston
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Re: Legal lights?

Post by freiston »

I really can't stress enough that if you want "legal" and good functional performance (in terms of illumination), the only "safe" option is to buy StVZO. If you want something good enough for moonless rural riding, get a minimum of 40 lux. Mine is 80 lux and I would say that 80 lux is a good bright light for any road in the UK. Seriously, I always feel thrilled as to how good it is when I ride on pitch black nights.
Disclaimer: Treat what I say with caution and if possible, wait for someone with more knowledge and experience to contribute. ;)
LancsGirl
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Re: Legal lights?

Post by LancsGirl »

freiston wrote: 10 Aug 2022, 2:14pm I really can't stress enough that if you want "legal" and good functional performance (in terms of illumination), the only "safe" option is to buy StVZO. If you want something good enough for moonless rural riding, get a minimum of 40 lux. Mine is 80 lux and I would say that 80 lux is a good bright light for any road in the UK. Seriously, I always feel thrilled as to how good it is when I ride on pitch black nights.
Thanks. Though this article - https://www.bikeradar.com/advice/buyers ... ke-lights/ - says that the cut off of StVZO isn't a legal requirement in the UK:
At present, bike light laws in the UK don’t require lights to have a cut-off. According to Duncan Dollimore, head of campaigns and advocacy at Cycling UK, the rules are pretty straightforward.

“In summary, you need a white light at the front and a red light at the rear, visible from the front and rear respectively and fixed to your bike,” Dollimore explains.
Please understand, I'm not saying you are incorrect, just trying to understand.

I'm actually trying to pack (including my new light!) so won't really have time to look anymore at the UK's sometimes confusing/inadequate/contradictory/ambiguous/ignored cycle lighting laws. But on first glance it looks as though the light I've bought may be anti-social (at least on its brightest setting, if not aimed downwards), but not actually illegal, in this country.

For this holiday that light will probably be OK. It's a back up in case I end up being out late, on very very quiet unlit roads. And given the time of year, it shouldn't happen much. And an advantage is it has umpteen modes, so I can switch to low power if I see cars approaching, which I will.

I'll investigate a less anti-social one when I get back, and the nights get darker earlier.

Thanks for your help.
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