Interesting article from 2005. I wonder if they were lower powered then.


The following one shows slightly worse effects of drag. Does losing 1-2 minutes on a 5 mile commute matter as Peter White wrote on his website? Probably not or at least to me plus not having to fuss with batteries on a commute makes it a no-brainer on a commuter bike. Does it matter on a cross country tour? Probably not. Does it matter on a 600K. Depends. How much is sleep worth or making the control? My battery powered alarm failed during one 600K and I slept a full 7 1/2 hours. I made first couple controls after sleeping in just the nick of time. Good thing my light was battery powered.

http://www.ctc.org.uk/file/public/fe...ub-dynamos.pdf

That was a wag on the part of Peter White, probably some bad schnapps or something. A minute on a 5 mile commute would mean pretty significant, noticeable drag. We all know that dynohubs have drag, but I really feel that it's in the noise level. I out-coast all the people I ride with except the recumbent riders. And furthermore, this is the long distance forum after all, this is where the multi-day riders are. It's possible to ride multi-day events with batteries, but if you ride as slow as I do a spare battery would be in order.

Peter is not far off on his swag.

Nonetheless, a dynohub's impact on speed is nothing compared to a poorly maintained chain or cheap tires. None of these (chain, tires, or dynohub) would be "noticible" but the losses are quantifiable and they have been.

muahhaahhaa....

For a simplified model.....if I use 7 watts loss (which would be when running the light as I am increasing likely to do these days...erm, even during the day...), a rider power output of 135W (55% of my FTP; about right for a randonee), total mass of 205lbs, minimal wind, Crr of .008 (so so tires on crap pavement), CdA of .25 m^2 (me on my Metabike), air density corresponding to room temperature and average pressure, and an average equivalent slope of 1% (equiv. to 6600 ft of climbing on a 200K)..... we see an 18 minute riding time difference on a 200K ride. (532 minutes vs. 550 minutes).

I could make up those 18 minutes without trying too hard by optimizing something else or by just trying slightly harder.

To this day, I've never ever noticed that my headlight was on without seeing the light. So yes, theoretically that drag is there, but it's just not something noticeable.

When I was a teenager, I had one of those bottle generators that rubbed on the side of the wheel, and yes, that thing WAS noticeable.
Something else to watch is that if you go back a few years, they'll be talking about incandescent bulbs on these things, and that might have been noticeably more drag, I never used one to compare.

I out coast the recumbents too. :p

Ten years ago it was a no-brainer. Generator hubs were the only way to go. With the newer LED technology it's not so clear cut. The lights are now so much better than they were and way more efficient too. I still prefer the generator hub just because I have bad memories of having to replace dead batteries on a cold, rainy, moonless night in the middle of nowhere. That was was no fun. I still use a battery light as a back-up. The resistance of the hub is pretty much not noticeable unless you are going real slow. On steep/long climbs I usually turn the generator off and use the battery light, more from a psychological viewpoint than anything else.

The light pattern from virtually all dyno lights is useful and does not piss drivers (and fellow randonneurs) off by blinding them. The light pattern from virtually all battery lights is symmetrical and pisses drivers and fellow randonneurs off when it blinds them. And if you tilt it down enough that it doesn't blind people, then you have an intense white spot that is too close to you and blinds you from being able to see long distance. An exception is the B&M Ixon IQ, but that is pretty heavy with 4 AA batteries and barely makes it through the night.

And I suggest you go re-read Peter's site. He's not great about updating reviews so there's a lot of stuff about how wonderful the beam pattern is on an E6. Other reviews of old technology LED's have also not been updated. But the photos of beam patterns tell the whole story ... look for the B&M Cyo Premium, B&M Luxos, and Edeluxe II, all of which use B&M's latest lens and LED technology. I have a Luxos-U and the beam pattern is so far superior that I doubt I'll use my old Cyo's except for commuting. The Luxos puts a beam all the way across the road so you can see well when you're going around corners on a mountain descent at 40mph.

Dyno power losses when the lights are switched off are negligible. Power losses when the lights are switched on are minimal. Over the last 8 years of riding with dyno hubs, I have ridden hundreds of miles in the daytime with my lights switched on because I forgot to switch them off and didn't notice they are on. With a Schmidt hub, and a modern LED light, the power loss is more like 4 or 5 watts than the 7 that you are using. For a randonneur, the premium is on being able to have reliable light that lights up the road usefully and properly at high speeds, night after night. If that costs a little bit of power at night, so be it. That said, like Homeyba when I'm on a steep climb and at the end of my rope, I'll sometimes turn my dynamo light off, mainly because of the psychology of having something that creates any additional drag (while not being necessary at 3mph).

My suggestion: If you are still puzzled about all of this, train yourself up for and then ride a 1200km. In the process, you'll be doing enough serious night-time riding with riders using all sorts of different lighting systems that direct observation will eliminate any puzzlement. And you'll have a lot of fun doing it.

Nick Bull

PS, The beam pattern on an E6 was really good, and with a dual E6 system you get pretty good light across the road. But it's still a bit like running a marathon at night while holding a candle lantern.

The Luxos is very, very good at illuminating the road. I am really glad I bought one. According to what I read, there are other lights that now match the Luxos, which is great. I read it on the internets, so it has to be true. The only complaint I have about it is climbing a mountain at slow rates it has a pretty obnoxious flicker. I'm thinking about upgrading my backup light for that situation, since I'm carrying it anyway. I've seen people say the luxos doesn't put out enough lumens, but, unlike some other lights I've used, I've never been in a situation where I needed or wanted more light. Going down a mountain with it is really an impressive thing. The cool thing about the U model is that if people think you have your brights on and flash you, you can flash them back with your "brights"

18 minutes on a 200 km ride would be just a bit less than 2 hours on a 1200 km ride.

I seriously doubt that it is that much. I rode my fastest 600k (just under 23hrs) using a generator hub. I don't think I could have gone anywhere near hour faster without it. You have to also take into account the fact that you are only pulling that higher wattage when the lights are on which is generally only at night. Plus you ride faster with better illumination of the road, especially on descents. So, it's not a simple wattage question.

btw, just like Nick, I've forgotten to turn my lights off in the morning or accidentally turned them on during the day without even noticing they were on.

I do not have too many miles on it yet but I have been happily using a Velogical rim dynamo with an Edelux II headlight. Endless power and no drag when you do not need it. http://www.velogical-engineering.com/rim-dynamo-en

http://www.webbuilder.hosteurope.de/...igp9757_v2.jpg

The faster you ride the less time you save.

Rim dynamo's are generally not the best option for long distance riding because of issues with reliability during inclement weather (ie rain). They tend to slip. Small imperfections in the rim's trueness will cause the dynamo to slip even when it's dry. Power output is lower than other dynamos. It doesn't even comply with StVZO's (German guidelines for vehicles on the road) 3W power output requirement at 15 km/h. I've also heard of wear issues with the small o-ring used to drive it. For cruising around town or short rides in dry weather it's probably ok. I wouldn't want to start a 1200k with one of those as my primary power source.

;) Still, the true amount of time that you are slowed is probably quite a bit less than that 18 minutes for a 200k. For the vast majority of randoneurs it's really a non-issue. I suppose if I was struggling to meet control time's it might be a consideration.

Perhaps so, but since this was Steamer's estimate would you address his assumptions and calculations?

Don't forget to factor in the lack of fatigue from having a bright light with an even distribution.

OP, personally when first jumping in I'd get a couple of these. Run both on low, should last through the night and provide plenty of light and redundancy.
http://www.fasttech.com/product/1443...00-lumen-white

If you end up doing a lot of night rides make the jump to dynamo lights.

Obviously as an RUSA Board member and one who runs long events, your advice is invaluable

Thank you very much for the direction/advice regarding headlamps. As I said, I am most unhappy with my reflector design on my Magic shine headlamp. It is utter trash. I was impressed with the patterns posted on Peter's site, which prompted me to consider purchasing one of these lamps and mating it to my own battery system. I have not yet found a solution but this is my direction. I am looking into the Ixon IQ Speed Premium lamp

With respect to power losses of dynohubs, I am not puzzled at all. We merely have different opinions. I have been riding and using lights since the 70's, have been on many night rides, and have a EE background. The dyno losses are not noticible but neither are they negligible. They are on par with a poorly maintained chain as shown by various reports published and linked on this thread. Of course, you are correct that distances beyond 600K a dynohub would shine brightest and be most beneficial if nothing more then for piece of mind. I carry complete redundancy systems. On 600km type rides, I never much needed lights and batteries have always served me well. I agree there. What is puzzling is why all of the the RAAM riders use dynohubs. There are places for battery systems and places for dynohubs. 1200K is likely the place where they make the most sense unless the organizer provides a drop bag service. I have little experience at that distance. My current battery system will provide 20 hours of light minimum. If a rider needs more than that much light during a 90H event, I wonder if they would make the time anyway.

The OP's needs were not quite clear because the distance, start time, and location of the event were not specified but we do know he/she requires light all night. If the rider is strong and the event were a 400K starting at 4am in a location with 14-16 hours of daylight, he might need less than 6 hours of power. Plenty of riders do the Frederick 400K in 15-19 hours and some riders manage to get 4-6 hours sleep on a 600k. If we assume all night means 10 hours of lighting and if he wants to use self contained non-replaceablebattery powered lights.........................

Based upon additional review of options, I think the following battery system would likely meet the OP's needs

Ixon IQ Speed & IQ Speed Premium......only significant drawback are the use of non-standard plugs which constrains battery options. It is only $200 and will run 10 hours and per Peter White's tests, the pattern and throw are very good.

http://www.peterwhitecycles.com/b&m.asp

To do a 600K in under 23 hours, your power/speed relationship was well outside the linear range. You probably ride the flats at 35kph+ where aerodynamics trump frictional losses rather quickly. The dynohub impact was probably more like 20 minutes on your time. For a slower rider using all of the allowed time, the impact would be over one hour.

well, the assumption that a rider will ride at exactly the same power level regardless of light choice probably isn't true. But that assumption is a really good starting point. And if the watts that are wasted cause one not to ride with a faster group of riders, then the time penalty could be huge. This is why Steamer contacted you to for your opinion about testing, it's certainly an interesting question to me.

I try to make him regret his decisions, as should we all.

Hi, Weatherby,

Just to be clear: I'm not on the RUSA Board, though my predecessor Bill Beck is.

The Ixon IQ's seem like really good battery lights. While I dinged it for weight, dynamo hubs themselves are not weightless. And running on AA batteries means that your battery resupply store is whatever convenience store you happen to be in. The IQ Premium is as bright as a Luxos or Edeluxe II, 80 lux. That is plenty bright enough. For me, since I already have a dyno hub, I don't need something quite as capable as the Ixon -- I just need something that'll let me limp in to the end in the unlikely event of dynamo system failure (which hasn't happened in 8 years).

I think the IQ Speed's are a mistake for long-distance riders. Peter says "This is my best battery powered headlight for a commuting cyclist." and "battery recharges in 6 hours". The Premium is only 10 lux brighter than the Ixon Premium--not enough to be worth its inconveniences.

But as you point out the OP told us almost nothing about their needs except "long distance event" which might mean 25 miles for many cyclists! And I'm not sure they've even revisited the forum!

Nick

I'm sure he has occasion to regret the day that he invited me along on that first ride

Haven't had that pleasure. I understand he's good at coasting, which can be a nice skill when you don't have much power.

made me laugh, but since I have even less power, I'm keeping my mouth shut