Vehicle: Bicycle
Self-heating grips   (+5)  [vote for, against]
Recover energy, recover feeling in fingers

My ride to work this morning was cold. My fingers were very cold.

If I had a hub brake, perhaps on the front wheel, then a heatpipe in the static member could absorb heat from braking. This heat could be used to warm the handlebar grips.

Mass of fluid in the system would determine how fast it heated up versus how long it stayed warm.

Turning the system on and off could perhaps be achieved by a lever mechanism to separate the reservoir from the brake caliper, thus preventing heat input.

A development of the system would incorporate a reservoir of water outside the hub instead. This would be heated via a heatpipe connection to the brake, but could also be pre-filled with hot water before setting out. A second heatpipe would take heat from the reservoir to the handlebars. Withdrawing this from the reservoir would turn the system off.

Primary heatpipe would need to be designed such that its entire contents boil at a safe temperature (e.g. 70C), ensuring that the main reservoir does not boil. This can be achieved by limiting the total volume of working fluid in the heatpipe.

Good for long rides on cold days.
-- david_scothern, Nov 30 2012

you may have to register... my appologies http://beta.marblar...hallenges/superfoam
superfoam can be made from conductive materials [4whom, Dec 03 2012]

I don't think a bicycle brake on a cold day would provide enough heat to do anything. You would be better off to get electric heated grips powered by a generator on the wheel.
-- DIYMatt, Nov 30 2012

I like the concept, and while I suspect that [DIYMatt]'s assumption that it's a bicycle is probably correct, the idea does not specify.

This could be made to work on a motorcycle, although the abundant complexities would make it fun. I too doubt that the brake hubs would generate much heat, but the liquid cooled bikes would lend themselves to this.

Having ridden motorcycle in Northern California winter and Colorado snow, I like this idea.
-- normzone, Nov 30 2012

Rather than hide behind my own ambiguity, I should admit that [DIYMatt] guessed correctly. Given that I only needed it to stay warm for a twenty-minute commute, the variant with a pre-filled hot water reservoir might be most viable.

Note that downhills are when a) most braking energy is available, and b) when the slipstream is at its cruellest - high speed, little pedalling to generate any body heat.

[update, after a few minutes on Excel] Stopping 80kg of man and bike from 20mph would generate enough energy to heat 100ml of water by 30 degrees. Maybe half of that could be passed into the system, if the rest of the hub brake were designed accordingly.

Particularly on a commute, with lots of stopping at junctions, this should be enough heat to keep the system going, but probably wouldn't be much good for bringing it up to temperature quickly in the first place. Pouring a mug of hot water (or coffee? Hmm...) into it to get it going might be a necessity.

There's clearly no reason why [normzone] couldn't put this on his motorbike either. Practically, electric heating must be easier - but I'm not sure this idea was ever entirely practical...
-- david_scothern, Nov 30 2012

Shirley there is a better way?

By means of flexible coupling shafts, make the ends of the handlebars rotate with the wheels. Over these handlebar ends, fit loose-fitting rubber grips. Then, braking can be accomplished simply by squeezing the grips, and the heat will be generated where it is needed.
-- MaxwellBuchanan, Nov 30 2012

Remove the handlebars, so you can steer (and brake) by gripping the front tyre with suitably gloved hands?
-- pocmloc, Nov 30 2012

Remove the brakes, and then your cold hands will be the least of your worries?
-- david_scothern, Nov 30 2012

There's should be an entire category Staying Warm: Two Wheeled Vehicle.

I used to have a pocket warmer that was a small hinged case with spun glass insulation and a bunch of small charcoal sticks.

A pocket hibachi, so to speak. I rode with it in the top of my motorcycle boots or in an inside jacket pocket.

Two of these in pockets in your gloves would do it.
-- normzone, Nov 30 2012

Fill the handlebar tube with charcoal ? Control heat output by bimetallic strips operating airflow dampers.
-- 8th of 7, Dec 02 2012

Then you could hang a coffeepot from the handlebars, and run a tube with a bite valve to your helmet.

I used to keep burritos on my cylinder head, 1972 Moto Guzzi Eldorado 850.
-- normzone, Dec 03 2012

//I used to keep burritos on my cylinder head,// All this time I have been trying to get my cylinder head into a taco...
-- 4whom, Dec 03 2012

...the bell tolls...
-- normzone, Dec 03 2012

With so much movement/energy on a bicycle not going towards forward motion I would imagine it a trivial task to direct some of it to the handlebars. It need not come from braking.

If you could keep some eccentricity between the outside frame of the handlebars and the inside diameter of the foam grips. And fashion the foam grips from a type in the above link, I reckon you could warm you paws...
-- 4whom, Dec 03 2012

I would think that a small hub generator and electric grip heaters (which both exist) would do the job more efficiently, and without the potential problem of a pivoting heatpipe.
-- Cedar Park, Dec 04 2012

random, halfbakery