What is a good grip material for heat insulation?

Question

As mentioned here earlier, an alloy handlebar works like a heatsink. Even with nicely padded pogies and with lobster gloves, silicone grips do a lousy job of insulating the heat. They slowly transfer the heat from hands to the center, where the stem and fork act as heatsinks.

One solution is to switch to a carbon handlebar, but perhaps a milder solution using grips with better insulation will do.

Silicone mittens are normally sufficient to remove a pot from a 400F/200C oven, but hold the pot for a few seconds, and the heat will soon reach your fingers.

Still, silicone may have been just "good enough" because the temperature difference between a pot out of the oven and my hands far exceed the temperature difference between the ambient riding temperature (-2C to +2C) and my hands, but I can now say from practical experience that simply holding the grips for two hours does drain the heat and one's fingers will start to freeze.

What is a good grip material for heat insulation?

Should you just "toughen up"?

How critical is it to get insulation right? If you're embarking on frostcycling, before listening to someone derisively and dismissively writing about toughening up, consider for a second that they may not actually know what they're talking about, and read carefully about frostbite.

Answer 1

Leather makes an excellent grip material, but being organic has maintenance.

You need to feed the leather with something like bees-wax, and keep it out of the weather where possible.

Leather can be formed and sewn into a slip-on grip, or wound on in a strip like other bartape.

Being organic, leather works fairly well to reduce heat transfer. Thickness is directly proportional to insulating factor.

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Insulation might work too - by isolating the grip from the bar you would reduce heat transference. Consider a thin layer of wool mat, or other fibrous material with a lot of air voids. Over the top wrap a different product that is hand-safe and will trap the underlying fibres.

Downside here is that moisture is to be avoided, and it is easy to dampen it with sweat, where the salt adds to corrosion hidden under the tape.

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Heat-shink Tubing I use this stuff occasionally for all sorts of repairs. A 150mm length of 30~35 mm diameter heatshrink costs cents when purchased from China in metre-lengths, and does an excellent job of covering up slimy grips and half-failed bar tape.

This would be an excellent top layer over some Pink Batts / rockwool or cheap foam bartape.

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Bar-heaters do work, but suffer the same issues as your hands in that they heat the bar underneath more than your hands.

I had a pair on a recumbent, and while they certainly made heat, it was lost to the bar and to the airstream. I ended up sewing some pogies around the grip area which helped immensely, as did layering some cheap foam bartape between bars and heater strip.

Main downside of bar heaters is getting power to them. These are designed for motorbikes where there is a continuous 12V power from the engine. My setup would run a pair of 18650 batteries flat in about 20 minutes, so I would only pulse them on for 30 seconds at a time.

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Exercise Part of the reason your hands get cold is because they're not doing a lot. Steering isn't exercising the hands, and I suspect you're on a long ride with minimal braking.

Instead, try moving your hands around in different positions. Drop bars give many positions, and even flat bars offer wide and narrower spots to hold.

On some particularly frosty rides, I've been known to tuck one hand between my back and my backpack (road bike) or simply resting on my tummy (recumbent) as long as the road is good, straight, level and open. Having such a hand position is not good for quick reactions. After a moment or two, swap to the other hand.

You can also just dangle an arm and flex the fingers. That alone can help get some blood flowing and invigorate the hand/digits.

Answer 2

Surviving with fingers intact in freezing temperatures requires paying attention to the thermal conductivity coefficient of both the handlebar and the grips.

Handlebars

The thermal conductivity coefficient of

• Alumin[i]um: 239 W/m/K,
• Steel: 50,
• Plastics and epoxy: 0.17-0.50, while
• Titanium ranges from 22.5 down to 5.8, from pure to alloy.

Aluminum (alloy) is the worst material for a handlebar when riding in freezing temperatures.

Grips

The thermal conductivity of some materials that have been used to manufacture grips is as follows. All are in W/m/K.

• Cork: 0.03 — 0.04
• Wood: 0.04
• Silicone: 0.2
• Polyurethane: 0.03
• Polyurethane foam: 0.03

Either switch to a more insulating material or increase the diameter of the grips.

Answer 3

My experience with handlebars has been:

• If you have an aluminum handlebar that's entirely bare, i.e. no bar tape (drop bars) or grips (flat bars), in cooler weather the heat transfer via the aluminum handlebar starts to cool down your hands before the airflow cools your hands so much you would need to use gloves entirely due to the airflow. Gloves could help, but then you need to use gloves so early that you should really consider using bar tape or grips.
• If you have any kind of good bar tape or grips, the heat transfer and airflow become problematic at about the same time.

So, I don't find it to be the case that grips would conduct heat too much. At the time when the grips become uncomfortably cold due to heat transfer via the aluminum handlebar, the cold airflow alone would cool your hands so much that using gloves is advisable.

You shouldn't really be looking at new grips. You should be looking at good gloves. On flat bars, gloves can make you survive at very freezing temperatures. On drop bars, there's an additional consideration: the gloves must be so thin that you are able to use your both small and big levers on your brifters (since bar-end shifters today are basically dead), which limits the glove thickness to so small value you don't survive much below zero degrees Celsius with those gloves.