Considering A Dynohub Front Wheel

[Razors Edge 6,545]

I'm considering a dynohub front wheel for my commuter/all-rounder. I would likely only use it during the dark evening rides of Nov-Mar, since it would be great never to have to charge my darn light's battery. 

Anyway, it got me thinking about having two different wheel hubs and the disc brakes relative to the centerline.  My question would be 1) how different is the disc brake location (assuming same rotor on both) and 2) how much of a PITA (or not) is it to adjust the brake for each swap between different wheels?  I also figure this would be an issue for where a cyclist uses a narrower tire on a wheel for one set of riding, but then has a second set of rims with fatter/different treads tires ready to be swapped on if there is a change to ride conditions (or, in a pit where a spare wheelset may be there if needed).

So, for the folks like @dennis, @ChrisL, @Dirtyhip, or even the wise @donkpow, how much of a PITA is it to swap between disk brake wheels?

 

[ChrisL 8,129]

I have never flip flopped between wheel sets but I have changes disc wheels on two bikes.  The first one required no caliper adjustment at all but swapped from one center lock set up to another using the same rotor

On the crosser I went from 6 bolt to center lock with an adapter.  The front wheel spun perfectly with no rub. The rear rubbed a bit so I loosened the caliper, squeezed the brake shut, tightened the caliper, released the brake & viola.  Took maybe 3 minutes.

[Dirtyhip 16,277]

LOL, I just swap out an entire bike.  One for snow, one for fast times, one for rain, one for pump tracks.  I am too lazy to change wheels off and on. 

[donkpow 3,949]

I wouldn't have any idea. It looks to me like you are asking if you swap hubs, do you have to adjust the caliper position?

[Razors Edge 6,545]

47 minutes ago, donkpow said:

I wouldn't have any idea. It looks to me like you are asking if you swap hubs, do you have to adjust the caliper position?

My feeling is that unless both wheels are identical, then the hubs will be different widths which would then put the disc rotor closer or father from the center of the wheel/hub.  So, when you grab wheel number 2 and fit it on the bike in place of wheel #1, the rotor will now likely rub against the caliper rather than sit nicely between the pads.

So, it is pretty much " The rear rubbed a bit so I loosened the caliper, squeezed the brake shut, tightened the caliper, released the brake & viola.  Took maybe 3 minutes. " situation like Chris wrote, where you swap them, but the "fix" or adjustment is pretty quick and easy????

I think, for me, the dyno wheel will come on the bike in Nov and come off in March, so it really will just be a swap I make a couple times a year, but it did get me wondering about if I had even another set of wheels for random conditions where it would be more likely I am swapping wheels more frequently.

[dennis 3,672]

I don't swap wheels often, but when I have it has not been a problem.

[donkpow 3,949]

3 hours ago, Razors Edge said:

but the "fix" or adjustment is pretty quick and easy????

The SRAM BB7 calipers I have are adjusted as easily as described. Technically, you move the pads into adjustment position, position the caliper, then adjust the pads' location. You could do it like Chis says, though. 

[dennis 3,672]

44 minutes ago, donkpow said:

The SRAM BB7 calipers I have are adjusted as easily as described. Technically, you move the pads into adjustment position, position the caliper, then adjust the pads' location. You could do it like Chis says, though. 

BB7s certainly are easy to adjust, but I have never understood why one side and be adjusted by hand and the other side needs the star tool. Any idea?

[donkpow 3,949]

10 hours ago, dennis said:

BB7s certainly are easy to adjust, but I have never understood why one side and be adjusted by hand and the other side needs the star tool. Any idea?

I don't know. I do know that it is easier to reach through the spokes to set the inside pad position with a tool even though the thing is like a knob and can be adjusted without a tool. I'd rather both could be adjusted by a tool.

[Page Turner 12,012]

 

...I commuted in the dark for many years back in ancient times.  I have experimented with available light systems, including the generator hubs of that era. Unless they've somehow overcome the basic problem of the dynohub only putting out power when you are moving, you're  better off with some of the best in rechargeable battery headlights and a simple rear flasher that runs off double A batteries.  Having your lights go dark every time you come to a stop does not make you feel seen and acknowledged by the surrounding traffic.

[donkpow 3,949]

49 minutes ago, Page Turner said:

overcome the basic problem of the dynohub only putting out power when you are moving

I believe they use capacitors now to store some energy for use at stop lights. I haven't looked at this specifically.

[dennis 3,672]

We need to get this for RE. $65 on ebay seems like a steal.

[donkpow 3,949]

When I worked at the co-op, those little generators sold out as soon as I posted them on Craig's List.

[Razors Edge 6,545]

On 11/28/2019 at 12:22 PM, Page Turner said:

 

...I commuted in the dark for many years back in ancient times.  I have experimented with available light systems, including the generator hubs of that era. Unless they've somehow overcome the basic problem of the dynohub only putting out power when you are moving, you're  better off with some of the best in rechargeable battery headlights and a simple rear flasher that runs off double A batteries.  Having your lights go dark every time you come to a stop does not make you feel seen and acknowledged by the surrounding traffic.

Modern tech is NUTSO:

" That true ultimate feature is the standlight! By having a small lithium polymer battery contained within, it will sustain full 90 lux output almost indefinitely while riding even at very low speeds, and for 15 minutes while stopped before beginning to diminish. I have ridden across town at night with my hub unplugged and not noticed. "

[donkpow 3,949]

The dyno thing is a good idea. Makes me wonder about the downside. Right up front I'm seeing a cost to benefit ratio problem when compared to battery operated lights.

[Razors Edge 6,545]

3 hours ago, donkpow said:

The dyno thing is a good idea. Makes me wonder about the downside. Right up front I'm seeing a cost to benefit ratio problem when compared to battery operated lights.

Yep.  That's the challenge with most cycling (or general) parts.  The incremental improvement of something over a similar item is usually a significant increase in cost.  So, a good set of lights might cost a couple hundred, but the wheel/hub/light would be closer to $600+.  Sure, it replaces a wheel and a light, so if you don't already have a front wheel, then the difference isn't so bad, but if you do have a good functioning wheel already, then it is a pricey addition.

For me, I would see using it with my "commuter" set-up, so it would generally have an all-around tire, and then I would have a second wheelset  with the more "adventure" oriented tires set-up, so I could transform readily from commuter to explorer mode by swapping out the wheels. 

But this is still all just pie-in-the-sky right now