Wrapping alloy brifters for cold weather

Question

I have a bike with alloy brifters that get very cold during winter season riding. I wear a nice pair of gloves and the cold comes right through because my hands are wrapped around them and usually in constant contact with some part of the alloy brake lever or the alloy shift paddle (Rival 22 Hydro). This gets uncomfortable, as I'm sure many others have found while riding in the cold.

This is not a problem at all when I'm riding my bike with carbon and/or plastic brifters.

I know why this happens and my question is what and how can I wrap the levers with in order to mitigate the conduction from them to my fingers in cold weather?

I'm concerned with interfering with the motion of the paddles and levers. I don't want them to be sticking or missing shifts because there is some bulky tape wrapped around them.

Are there any materials and methods others have used successfully? Also, I'm not really interested in bar mits as a solution.

Answer 1

Do you care about originality ? Consider changing the brifters for something made from plastic or carbon because as you've noted, they don't suffer the same issue. Likely to be an expensive solution.

So, can you paint your brifter's outside surfaces with an acrylic enamel paint? you'll need many thin coats to build up a thick layer that won't abrade easily. Sand between coats and add some clear coats as the top layer. Avoid painting "under" the brake lever where it faces the gear change lever.

Instead of paint, you might choose to use a product called Plastidip, which historically was used for dipping tool handles, but more recently comes in a spray can and has been used for car wheel rims, etc. This stuff comes in multiple colours.

You can also get sticky-backed cork tiles/sheet which is under 2mm thick. Some creative pattern work and you should be able to put some heat-insulating cork between you and the cold bits. Do apply sealant/varnish to the cork to protect it from the cold.

Leather is another valid alternative to cork.

Finally, you wear gloves already, so assume they are full-finger. You could add heating wires to the gloves and run them off a small USB battery in your back pocket, or add heating wires to the brifters themselves and mount the battery on the bike frame.

If you do get a choice of colour, I'd suggest black, or as dark as possible to increase heat insolation from any sunlight.

Answer 2

There's a self-setting, moldable plastic called Sugru that many folks use to mold their own grips. It's very heat insulating and is good to very hot and cold temperatures. Since you can mold it your fingers before it sets, you can control the thickness and form.

I used to wrap the grip of my brass water hose gun as it got too cold to grip on early spring days. The Sugru home page gives many other examples of its uses. Google images gives examples of people using Sugru for bars and brifter hoods but i didn't see any brifters themselves.

Disclaimer: no relation to sugru except as an avid user.

Answer 3

One might use heat-shrink tubes.

It adds about half a millimetre to the underside. This might or might not work, depending on the shape of the brake lever's underside and the gap to the shift lever.

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Why I think none of these solutions will solve the problem:

The real difference here is not the temperature of the metal levers but the much greater heat conductivity in the bulk of the material compared to polymer levers. Even though the specific heat is lower.

The small extra layer of insulation will make not much difference when one uses a much thicker insulation layer on the gloves already. Any insulation will only slow down the cooling out of the levers slightly.

The high heat conductivity requires that a larger volume of the material has to be warmed when touched by ones hand. This might outweigh difference in specific heat considerably (compare the example values below).

Specific heat c (kJ/kg K):

Polyamide (PA6): 1.7

C, graphite: 0.71

Al: 0.9

Heat conductivity k [W m^-1 K^-1]:

PA6: 0.3

C, graphite: 168

Al: 205

Note: These values only ought to give an idea of the orders of magnitude, they depend on temperature and composition. The graphite values ought to give an upper boundary for carbon fibres, lengthwise. Fibre reinforced composites for such parts often use short fibres, which leads to more isotropic mechanical properties, but also thermal conductivity. One can assume that the polymer matrix (PA6 is only an example here) dominates it for the composite.

sources: google, engineeringtoolbox, data sheet