Sturmey-Archer X-FDD Hub Dynamo

[monkey_boy]

I am selecting components for my new LHT build and was offered a Sturmey-Archer X-FDD Hub Dynamo for 40$CND extra. Just curious if anyone has any experience with this specific dynamo. What is the drag when both on and off.

Thank you.

[K6-III]

Go for it, minimal drag when off, awesome drum brake.

[BikeManDan]

I just built a wheel around this hub but have yet to test it on a bike.

The one thing I noticed about it is that it has an incredibly notchy feel to it

[K6-III]

That's the dynohub. Don't feel it on the road.

[Hydrated]

I am very interested in this hub... for a couple of reasons. I saw your posts about this hub earlier, K6... and I'd love to get some feedback from you or anyone else who has experience with dynohubs and/or drum brakes.


Lighting. I currently run a dual 20W halogen setup with a lightbrain controller, and it's like having flamethrowers out front to light the way. The batteries are a pain, though... recharging and constantly doing the mental calculations to figure out if I'll have enough juice to get me home in the pitch black rural area that I live in. I realize that I will not get the same levels of light from a dynohub setup, but will I get enough light to truly see by? I have a couple of fairly signifigant downhill runs, and I don't want to outrun my lights at 30MPH. I'm a nerd engineer, so feel free to talk techie if necessary! :)
Braking. I recently had a near miss where a car started to pull out in front of me on wet pavement... and it scared the crap out of me. I saw him ahead of time and knew he didn't see me. I was going downhill @ about 25 - 30MPH and started riding the brake levers to clear my cantilever brakes. But the brakes would not clear and start braking! I was bombing straight at this car's driver door with no way to stop. Fortunately, he saw me at the last minute and stopped as I swerved around him. I keep my brakes in top condition, and I run high quality pads... so I've decided that I simply need more dependable braking for my fully loaded commuter. That's a lot of weight to haul to a stop. I've thought about disc brakes, but the drums appeal to me if the stopping power is really close to that of discs. And what is the lifespan like... and what do you do for drum brake maintenance? How do the drum brakes really stack up?


In addition, using this hub wouldn't require a fork swap like going to disc brakes would. It seems that the choices of road forks with disc brake bosses is getting better, but is still somewhat limited compared to the selection of non-disc road forks.

Thanks for the help..
Bobby

[n4zou]

Lighting. I currently run a dual 20W halogen setup with a lightbrain controller, and it's like having flamethrowers out front to light the way. The batteries are a pain, though... recharging and constantly doing the mental calculations to figure out if I'll have enough juice to get me home in the pitch black rural area that I live in. I realize that I will not get the same levels of light from a dynohub setup, but will I get enough light to truly see by? I have a couple of fairly signifigant downhill runs, and I don't want to outrun my lights at 30MPH. I'm a nerd engineer, so feel free to talk techie if necessary! :)

You could use a dynamo lighting system in addition to your present battery powered system. This would provide battery free night riding when your very bright lights are not required. Just engage the dynamo and ride with your dynamo light and when you need light for that down hill run just turn on your flamethrowers.

I built my own dynamo light using a Luxeon Fraen elliptical lens and holder from luxeonstar.com.
http://www.luxeonstar.com/item.php?id=462&link_str=121::125&partno=FHS-HEB1-LL01-H

I originally purchased a 1-watt Lambertian LED from the same site and used it in the lens and holder for about a year. Subsequently DX stocked an LED with over twice the lumen ratting of the Luxeon star.

http://www.dealextreme.com/details.dx/sku.1445

The upgrade LED fit perfectly in the Luxeon holder and lens and due to the pure white produced by the Seoul Z-LED emitter the beam pattern actually narrowed improving it considerably. One thing I did not like about the Luxeon lens and holder was the requirement to melt the plastic legs over the heat sink normally making it non-upgradeable. I simply used a little hot glue around each leg while pressing down on the heat sink to ensure a good tight fit. This allowed easy removal of the old glue by simply pealing it away. After installing the new LED I reassembled the light using the same hot glue technique. The Luxeon holder and lens with LED and heat sink fit nicely in a 1" PVC pipe coupler available for less than a $1 at any hardware or building supply store in the plumbing section. I used a prescription bottle cap that press fit over the 1" pipe coupler to hold clear plastic over the lens to protect it. Here is a photo of the light on my bike.
http://i143.photobucket.com/albums/r154/n4zou/Hpim0312.jpg

As for light output from my dynamo and LED headlight, with the new Seoul Z-LED light output and pattern is slightly better than a friends night rider 5-watt halogen setup. Light output is good at sub 15 MPH speeds and allows you to actually see where your going so it's not just "be seen" lighting.

[K6-III]

I am very interested in this hub... for a couple of reasons. I saw your posts about this hub earlier, K6... and I'd love to get some feedback from you or anyone else who has experience with dynohubs and/or drum brakes.


Lighting. I currently run a dual 20W halogen setup with a lightbrain controller, and it's like having flamethrowers out front to light the way. The batteries are a pain, though... recharging and constantly doing the mental calculations to figure out if I'll have enough juice to get me home in the pitch black rural area that I live in. I realize that I will not get the same levels of light from a dynohub setup, but will I get enough light to truly see by? I have a couple of fairly signifigant downhill runs, and I don't want to outrun my lights at 30MPH. I'm a nerd engineer, so feel free to talk techie if necessary! :)
Braking. I recently had a near miss where a car started to pull out in front of me on wet pavement... and it scared the crap out of me. I saw him ahead of time and knew he didn't see me. I was going downhill @ about 25 - 30MPH and started riding the brake levers to clear my cantilever brakes. But the brakes would not clear and start braking! I was bombing straight at this car's driver door with no way to stop. Fortunately, he saw me at the last minute and stopped as I swerved around him. I keep my brakes in top condition, and I run high quality pads... so I've decided that I simply need more dependable braking for my fully loaded commuter. That's a lot of weight to haul to a stop. I've thought about disc brakes, but the drums appeal to me if the stopping power is really close to that of discs. And what is the lifespan like... and what do you do for drum brake maintenance? How do the drum brakes really stack up?


In addition, using this hub wouldn't require a fork swap like going to disc brakes would. It seems that the choices of road forks with disc brake bosses is getting better, but is still somewhat limited compared to the selection of non-disc road forks.

Thanks for the help..
Bobby

I've been running the XFDD for a few months now of solid winter commuting. In dry weather, it is a moderate improvement over caliper brakes. In wet weather, it blows caliper brakes out of the water. The main thing is that your fork is fairly stiff laterally, as the reaction arm does bend the fork back a bit on my Raleigh 3 speed. On my touring setup with the XFD (non-dynamo drum), the fork is much stiffer, leading to better braking. In wet weather, the sealed nature of the drums makes them on par with discs. In dry weather, the discs are stronger, but either can stop you very well in dry weather. As for brake maintenaince, there is none---all you do is tighten the cable tension barrel for the first few weeks of riding. Drum pads last nearly forever, so nothing to worry about there, but if you need them, J&B stocks replacements (your LBS can order from them) and QBP should be doing so shortly.