Winter Cycling - New way to help cold feet?

I came up with an idea today to help keep my feet warm (I hope!). My shoes are too tight to add more socks or to add thicker insoles so I decided to make the insoles I have more efficient. I glued a layer of emergency blanket material to the underside of the soles to help insulate my feet. What do you think?

http://varroa.googlepages.com/insoles.jpg

http://www.thermalinsoles.com/

varroa,

I think that you want the reflective material right next to your skin and with the foam insole as a barrier between the space blanket material and the sole of the shoe.

The reflective layer must be next to your skin or they will not work. In fact, the metalized layer may improve the conductivity of heat and make your shoe colder the way it is.

The metalized layer must be close to the skin with little or nothing in between. It is meant to reflect heat back to a warm surface. Agains't the cold sole of your shoe it may only improve the flow of heat out of the shoe. Heat always travels from hot to cold. So getting cold always amounts to losing heat. THe shiny metalized layer is meant to slow this down by reflecting heat back to the warm body.

varroa,

I think that you want the reflective material right next to your skin and with the foam insole as a barrier between the space blanket material and the sole of the shoe.

The reflective layer must be next to your skin or they will not work. In fact, the metalized layer may improve the conductivity of heat and make your shoe colder the way it is.

The metalized layer must be close to the skin with little or nothing in between. It is meant to reflect heat back to a warm surface. Agains't the cold sole of your shoe it may only improve the flow of heat out of the shoe. Heat always travels from hot to cold. So getting cold always amounts to losing heat. THe shiny metalized layer is meant to slow this down by reflecting heat back to the warm body.

Actually if you look at most boots rated to -30c they have a layer of the reflective silver material sandwhiched between two layers of felt so it is not essential to have it next to your skin (there are many other example of this as well).

I think that when used in a shoe it is perhaps necessary to have some kind of absorbative barrier between the foil and the foot. Because moisture from our foot would make the foil surface too slippery. But even so, the reflective surface needs to be towards the skin for best effect. And since the improvement in insulation is small you can't afford to loose any of the benefit.

THe foil is bonded to mylar or something similar to hold it without tearing. Since the mylar is plastic it has a different specific heat than metal and causes a small resistive barrier to heat transfer. So some heat will be reflected back but it can't work properly if it's backwards.

Correct me if I am wrong, but in the picture it looks like the reflective side of the space material is facing the outside of the insole and will face the bottom of the shoe instead of your foot.

The felt may also perform another duty and that is to keep the shiny metal clean and shiny since it works better that way.

Now it's possible that the material looks shiny on both sides. And it's hard to tell the difference and which side is which. But the plastic bonding material should be facing out.

When the metal faces outward from your foot the heat leaving your foot will go through the insole and then the mylar backing and when it hits the metal layer it will speed up the heat transfer. When the heat is going through the metal first a resistance is caused because the metal transfers heat faster than the mylar backing. The resistance cause's some heat energy to be reflected back. But this only works in one direction.

Varroa, it sure is worth a try - nothing to lose. Have you tried them yet? Give them a try and let us know how it works. I think there is a great need for some kind of thin warm insulator for bicycling shoes. You may have come upon a great idea

I can't tell yet if this has helped any as the temperatures have gone up above freezing. When the temp drops below freezing I should be able to tell if it helps any.

The foil is shinny both sides and it is glued to the underside of my insoles (That is a pair of left and right insoles and the left one is turned upsided down to show the reflective layer.

Come to think of it. A thin reflective metal sandwiched between two felt layers would essentailly work the same way since the second piece of felt would work as a heat resistant flow boundary.

If you want to go further with your experiment and make your shoes more rigid at the same time. This might be great for some inexpensive mountain biking shoes. Try making a thin heat reflector like some winter boots use. Mold a thin polished aluminum plate to your foot by puttin it inside your shoes and walking a bit. Then take it out and glue a thin piece of felt on both sides and put it back in the shoe and see how it works.

This does work I've been using thin pieces of reflextex(Brand Name?) insulation for a few years now. The insulation is no more then very very thin bubble wrap inside two foil layers. They last about week per pair. I just buy a 3' by 24" rolled up sheet. They sell it by the foot. I bet the felt works even better.

plastic bag

I tape a few patches of reflective mylar over the cleat plate in my shoe, shiny side up, under the insole. Can't hurt...

i mount my cleats over top of the booties rather than cut out for them.. this keeps a layer of rubber sole between the pedal and sole of the shoe.. less cold transferance.. and the bootie still flips over the heal to air out the inners...

This does work I've been using thin pieces of reflextex(Brand Name?) insulation for a few years now. The insulation is no more then very very thin bubble wrap inside two foil layers. They last about week per pair. I just buy a 3' by 24" rolled up sheet. They sell it by the foot. I bet the felt works even better.

Sorry to burst anyone's bubble, but other than Gojohnnygo's post, most of what's being discussed in this thread will not take advantage of the insulation potential of a reflective surface.

A reflective surface is only an effective insulator if it faces an air space. It doesn't matter whether the shiny side faces toward the warm surface or away from it, the effect is the same. That's about the long and short of it.

Gojohnnygo's suggestion is two reflective surfaces separated by an air space in the form of bubble wrap, which should be a fairly decent insulator for its thickness.

that type of material insulates against radiative heat loss (types of heat loss are radiation, convection, conduction, evaporation). I would think in a shoe environment the amount of heat radiating out from your soles would be minimal, of much greater import would be conductive heat loss through the cold pedal and convection, the heat dissipating as your foot circulates through the pedal stroke in constantly cool air.

Sorry to burst anyone's bubble, but other than Gojohnnygo's post, most of what's being discussed in this thread will not take advantage of the insulation potential of a reflective surface.

A reflective surface is only an effective insulator if it faces an air space. It doesn't matter whether the shiny side faces toward the warm surface or away from it, the effect is the same. That's about the long and short of it.

Gojohnnygo's suggestion is two reflective surfaces separated by an air space in the form of bubble wrap, which should be a fairly decent insulator for its thickness.

Yes true but many insoles are made out of closed cell foam or open cell foam. With closed cell being the warmest. Foam can be a great insulator with its ability to trap many air bubbles. They use closed cell foam sleeping pads in very cold environments.

I ordered a set of these http://www.toastyfeet.com/ earlier this week, and I plan to try them out tomorrow morning. In theory they should be way better than any sort of reflective barrier.

Let us know how they work for you and are they better than chem pack's.thanks, vger

I'd think bare metal would make it much colder. Ever try cycling in the winter using handlebars with no grips?

I ordered a set of these http://www.toastyfeet.com/ earlier this week, and I plan to try them out tomorrow morning. In theory they should be way better than any sort of reflective barrier.

So I tried this out today, and it didn't seem like it was making a whole lot of difference. However, my Sealskinz Chillblocker socks showed up today, and that seemed to pretty much eliminate the problem. It was around 30F with 20mph winds on the way home, and I wore the sealskinz, a thin liner sock, my normal shoes and performance toe covers. Feet stayed warm the whole way home.

I say that I have to agree with Waffenschmidt,

Trying to improve the radiant heat loss is kind of like working on the least significant problem. My feeling is that conductive and convective heat losses would be orders of magnitude larger than any radiant heat loss.

I think you have to recognize the limitations of the space blanket principle. I mean no one stays warm on a cold mountain with a space blanket. It's far less effective than a sleeping bag.

Yes, that would also be my asumption,if your in a negative degree situation the only thing that makes sence to me is a generation of heat from a heat sourse,batteries, chemical packs etc!Even when you keep your core warm and head warm, you still need a little for the toesies-10-4?

So I tried this out today, and it didn't seem like it was making a whole lot of difference. However, my Sealskinz Chillblocker socks showed up today, and that seemed to pretty much eliminate the problem. It was around 30F with 20mph winds on the way home, and I wore the sealskinz, a thin liner sock, my normal shoes and performance toe covers. Feet stayed warm the whole way home.

How thick are the Chillblockers as compared to a typical road sock? I just ordered a pair also and I'm hoping they fit in my 3 season road shoes...

p.s. I read your blog, I agree wholeheartedly about that particular Performance shop. I will NEVER set foot in there again.

bump

I used the Toasty Feet insoles for the first time this evening, darn warm weather. They helped. It was the first time my feet did not get cold on a ride. The temperature was 28 degrees Fahrenheit and we were out for one hour and 45 minutes. I was wearing Shimano SHR-130, DeFeet Aerator, SmartWool sock, and Louis Garneau Protects. I will go to chemical warmers if it gets colder.

I use these....

HeatMax socks with toe pouch...these,along with foot powder (prevents moisture) keep my feet nice and comfortable in my old winter biking boots......i tried out this combo a couple weeks ago in a 2-above windchill along the Chicago lakefront...

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p.s. I read your blog, I agree wholeheartedly about that particular Performance shop. I will NEVER set foot in there again.

I thought I was the only one with that experience. I've bought 6 bikes from PBS (my 1st hybrid and 4 kids' bikes - the most recent one was from their outlet shop on eBay) - so I don't have a problem with the equipment, but the Fairfax store experience leaves something to be desired. Reston is a bit better, but Spokes (Ashburn and Vienna), A-1 (Herndon) and Bike Stop (Springfield) are very well run shops.