69ing the Big Dummy: An Enlightening Experience
About a week or so ago I was over at Adam and Benson’s place for some dinner. As these evenings usually go, we ended up in their garage, which doubles as a veritable mecca of all things bicycling.
I had ridden the big dummy up there, and as we walked around looking at some of the new voodoo prototypes we started discussing my acquisition.
We discussed the Big Dummy and its utter domination of all things cargo-related, and the pros and cons of it compared to a more traditional touring rig. Eventually, we hauled it into the shop and started playing around with different front wheels.
Turns out that the Big Dummy fork will not only fit a 29er wheel in it, but will fit a 29er wheel with a big-ass 2.5” tire as well. Hmm. . . .
About a half-hour later, I was cruising home with a 29er front wheel with a shimano dynamo front hub on it. It’s supposedly one of the more efficient dynamo hubs on the market, and it generates a modest 6V and 3W (kinda the standard for dynamo hubs).
It’s been about a week now, and I have to say that the 29er front wheel is pretty sweet. Since the wheelbase on the bike is so long, the head angle hardly changed at all when we added the extra diameter of the 29er wheel. This means the bike handling didn’t really change that much. I do notice the extra rotational inertia of the wheel, which means it rolls over stuff a little more, and takes a little more effort to lay the bike into a turn, but I got used to it pretty quick.
I think, in the end, the 29er didn’t make a huge difference on the bike handling, but it did make it a little easier on hitting potholes or pulling the bike up a curb. I actually think the 29er would have been a really nice choice for the rear wheel, because the front is still relatively easy to pop up for curbs and such, but the back wheel has a tendency to just STOP when it hits an obstacle (and it just gets worse with more load). I think the 29er rear would help that problem.
The front dynamo hub?
Eh. I’m on the fence about it.
There’s definitely some rolling resistance to it when the light is on. I can’t tell if there is some when it’s off (probably a bit, just based on spinning the wheel). The hub is alright, and resistance is noticeable, but isn’t too bad when you have the light on.
The light, however, needs some serious work. First off, I know it’s possible to have a capacitor in there which would keep the light going for a minute or so if you slow down too much or come up to a stoplight. You have tons of power to spare coasting downhill (think regenerative braking in cars) so why not use it when you hit that red light? As it is, the light just kinda sputters out as you come up to a stop, and then you’re stuck in the dark until you start up again. I like being seen at stoplights right before I’m about to start up again. Also, the light isn’t the brightest thing. I would think for 3 watts of power output, you could be rockin a SUPER bright LED setup. Instead, I think the light is just a crappy halogen. I give it a few weeks of the starting, stopping, and sputtering out before the bulb burns out.
Now, don’t get me wrong, I think this is a cool system, and I would love to see it take off, but the stoplight thing and the light just being downright crappy need to be fixed. Benson said that there’s some other companies that make lights which are compatible with these hubs.
A quick search revealed some really nice options, some of which even have the capacitor for stoplights. Now we’re talking. Nice work with the hub, shimano, but we always knew you weren’t a light company. . .
It’s also tough to justify the expenditure and extra rolling resistance of this option when there are cheap LED lights out there which will put out a similar amount of light as the shimano light, and last several hundred hours on a pair of AAs. Like I said, I’m take-it-or-leave-it on the dynamo at this point. Maybe a different light would sway me, but I got what I got, so that’s how I see it.
Hello Nathan,
I enjoy the info you post and the descriptions of the Flagstaff biking scene…I miss it. Regarding the above blog entry, I felt compelled to say you forgot one major point about the Shimano generator hub compared to the other ones you briefly mention…it’s very inexpensive. I ride/commute nearly every day using the nexus generated hub you discuss and I think it’s pretty nice in concert with the halogen shimano light. Instead of a couple hundred hours of use with AA or AAA batteries you will no doubt get a few years of constant use out of it. (I’ve had mine for two and it’s still going). Not only that but the bulb is a couple dollars to replace. In my opinion, it’splenty bright for night commuting and urban riding in general and you will never forget to reload (or buy) batteries again….a much environmentally intelligent decision. I also feel as thought the back eletromotive force or, as you say, “resistance”, during light-on riding is very minimal…really only noticeable while riding when you are really hauling ass down a hill. Although it’s probably not for racing (however I know a big gay guy that raced the old pueblo with one) I wouldn’t spit hairs about it’s “resistance”, i.e. a tough guy like you should enjoy the extra work out. As you mentioned, there are many other great lights out there that will work with the shimano generator hub, but you will undoubtably pay much more for it…anywhere from 2X to 5X as much…the shimano light is around 40.00 retail.
JQP
- JQP
Link | July 11th, 2008 at 12:12 am
JQP - I definitely agree that it’s a much more environmentally responsible option. In reality, the rolling resistance is really not that big a deal, especially since when you turn the light off it is pretty close to zero, which is a huge advantage over some of the other dynamo hubs out there. I think the thing that drove me away from it was more the light. I feel like for 6V and 3W you should have a lot more power output (based on some other lights which run off about 3W of power), and if environmentally responsible is a goal, it seems like a high intensity LED setup would last pretty much forever versus the ‘couple dollar bulbs’ that need to be replaced.
How often do you go through bulbs on yours?
I agree as well that the shimano light is very cost-effective, but I’m a firm believer that ‘cheap’ doesn’t have to mean ‘not well designed’ and I think the light has some shortcomings which could have been designed out while still keeping the price reasonable. It seems to blast a lot of extranneous light up instead of forward, and the little LED on it really doesn’t add anything to your visibility, but undoubtedly takes up some power that could be put towards the main bulb.
Maybe it’s just the engineer/designer in me?
- Nathan
Link | July 11th, 2008 at 6:46 am
Nathan,
It’s true the LED seems pointless. I originally thought it might confer visibility during the day but it really doesn’t.
I have never replaced the bulb in two years…and I often forget to turn it off in the AM after riding home in the dark the previous night.
Another bonus of the low cost…at least in Tucson…is that people like to steal them. Maybe another flaw is the lack of ability to bolt the light to the bike more permanently. I have managed to do it (sorta), but it was really designed to clamp the handlebar in a rather simple/cheap way.
take care, JQP
- JQP
Link | July 11th, 2008 at 10:23 am