AngrySaki

I have a relatively old pair of Lake MXZ-302's and as part of the insole, the have a layer of what is pretty much bubble wrap. The problem is that all the bubbles are popped/compressed around the ball of my foot. My feet have been getting pretty cold this year and I'm thinking this might be part of the reason.

I noticed that 45NRTH makes a pair of insoles, which I would probably buy if I could get them quickly, but winter is almost over and by the time I get them, it'll probably be over. If I can't find another good replacement, I'll probably get the 45NRTH insoles for next year.

A temporary hack that lasts a month would probably be fine. My first thought was just to cut up a couple of wool socks and layer them as the insole. Does anybody have an ideas of what I should replace them with?

pyze-guy

You could use thin styrofoam , the kind that meat is sold on from the grocery store and cut it out in the shape/size of your insole. Or buy some felt insoles from pretty much anywhere.

erig007

Wool felt and aluminum insoles is what i have in my mukluks.
Cardboard can work too.

cyccommute 

These are similar to the 45NRTH. They use an aerogel for insulation which reduces bulk. I replaced the Lake insoles with them and they are quite effective. For extra comfort, I added fleece insoles on top of them. The fleece adds a little insulation but is the mainly for comfort.

Aerogel is wonderful stuff. We use it for high temperature insulation instead (or in addition to) glass wool. At 800C, 10mm (1/4") of aerogel does the same job as 100mm of glass wool.

AngrySaki

Aerogel will make me faster right?

I think I'll check out a couple of stores tonight and see if they have anything like those toasty feet. Otherwise I'll just hack something out of foam or felt or something.

cyccommute 

It is light

erig007

Wondering if aerogel is stable in time. I saw a youtube video a while ago showing a guy making aerogel, the guy wasn't very enthousiast about how long the bmix would last.
I have still in mind the primaloft scam that is wonderful at first but collapse after a few use.

cyccommute 

The aerogel is very stable as a material. It's silica gel which is a special crystalline form of silicon dioxide which is also known as quartz. The aerogel is not very tough and breaks easily but in the insole it is infused into a fabric to keep it in place. That fabric is then encapsulated in a foam rubber cover. It won't go anywhere nor will it compact like other types of insulation will.

erig007

I see here a trade-off some way. Cold will go through the fabric (or the foam rubber) instead of aerogel. Nature always goes the easiest way.
My wool felt insole is no better probably half its original thickness now so there is probably always a trade-off somewhere.
I've just read from wiki that aerogel is a poor radiative insulator. Problem easy to solve with an aluminum layer anyway.
I also read from wiki that the more pressure there is on it worst the insulation become. Probably still better than other type of insulation but someone that weight 60kg/75kg/90kg on a tiny feet surface is more than the 2.5kg that the picture shows on wiki. Must be the reason why it is infused into fabric

https://en.wikipedia.org/wiki/Aerogel

AngrySaki

I found some aerogel inserts at a store last night: https://www.marks.com/shop/en/marks-m...insoles--31977
I have a ride planned Saturday morning and it's going to be -16C, so I'll see if they make a difference.

erig007

Don't forget the aluminum foil under, aerogel seems to be weak against radiative heat.


In my mukluks i use double face tape used for plastic films on windows to make my different insoles stick together and to the mukluk. Doesn't move at all. Still going strong a year later.
(cover the aluminum with duct tape to make it stronger)
To make a "reflective" insole, roll the aluminum to make 3 layers at least as wide as an insole, cover with tape then cut it the shape of your insole.
Doesn't cost more than 2 or 3$ to make.

AngrySaki

Do you think aluminum would work better than emergency blanket material? I already have an emergency blanket partly cut up.

cyccommute 

I think you are misinterpreting what you have read and misunderstanding how the aerogel works in the insole.

First, the fabric. The fabric that is infused with the aerogel is encapsulated within a foam rubber shell. Both offer some resistance to heat transport but neither rises to the level of the aerogel. The aerogel is ground up into a powder and coats the inner fabric all the way through it. The aerogel can be thought of as a whole lot of air bubbles (millions per cubic centimeter). Even when it is ground to a fine powder, there is enough dead space to make it highly effective as an insulator. Heat (or cold) trying to get through the aerogel has to get though all those bubbles of dead air as well as try to get through the silica gel which is a good insulator in its own right.

You are right in that the radiative properties are rather low but it is a transparent material. At low temperature, radiative transport is low however. But there are 3 components to the way thermal energy passes through a material...solid conductivity, gaseous conductivity and radiative conductivity. The solid material that the aerogel contains doesn't conduct heat all that well. The gases it has trapped don't conduct heat well either. And the radiative conductivity is low at cold temperatures. Additionally, all three of these mechanisms work together and can't really be isolated from each other. Changing one property will have an effect on the other properties.

This article explains it a bit better than the Wiki article does.

I've used the aerogel insoles a few times now. They do as advertised. They are warm enough that my feet don't get cold on the bottom but I can feel cold infiltration on top of my feet.

erig007

I currently use it in my mitts and mukluks. I was using it before in my mitts but the result wasn't extraordinary with just one aluminum layer. I could barely ride at 20F and still had to add a liner.
With 3 layers the result is just amazing i haven't reached the bottom limit this year but i can go up to -20F and still be warm.
For my feet, my mukluks are warm enough so i haven't felt the need to improve the reflective insoles that are sold with the mukluks yet.
DIYing it doesn't cost much so the risk is pretty low anyway. Combined with aerogel it should be fantastic i believe.

erig007

Thanks for the clarification. I was imagining it more like honeycomb with aerogel instead of honey. By the way, from wiki the new aerogel champion since 2013 is graphene aerogel.

Regarding, how the aerogel rubber combo protect against cold my point is still valid. Since rubber isn't as good insulator as aerogel what prevent cold from getting around aerogel rather than going through it. My wool felt insole is 100% wool so cold has no choice but to go through. An aerogel insole (at least the one we're talking about) isn't made only of aerogel so cold can still go through rubber instead. Like this

Myosmith

My vote is for wool felt insoles. They are effective, inexpensive, and help even when damp. They can wear and compress over a season or two, but they are cheap enough to replace. I have a pair that has a mylar/tyvek looking layer on one side.

marathon marke

I know this thread is about insoles, but I just wanted to share my own experience. I picked these boots up from Salomon several week ago, and even with the -20 F and near -50 wind chills that the polar vortex brought us in Wisconsin, I haven't even come close to experiencing cold feet. I've been using them when riding my fat bike. I believe Salomon uses Aerogel in not only the insoles, but also the boot's upper.

cyccommute 

To get a better representation of how the insulation works, turn the orange circle perpendicular to the flow lines and flatten it out. The rubber used in the insole covers a internal fabric that is infused with the aerogel. It's not in contact with the aerogel particles other than the ones on the surface of the fabric. Cold air may be able to seep in at the extreme edges of the insole but your foot shouldn't be near those edges and the edges are very small...on the order of a couple of mm on both sides. The fabric inside has a large quantity of the aerogel. The gel does the job of insulation rather than the fabric.


The aerogel insoles aren't that expensive and you could probably soak the material in water and not lose its insulating capability. The silica gels used for aerogels are treated to be hydrophobic and the trapped air in the matrix will be unaffected by water. It also takes much, much, much less in terms of thickness to get the same insulation value. I've already mentioned that we use this stuff with 800C (1475F) reactors at work. 6" of the glass wool that we use is the equivalent of feet of the kind of fiberglass insulation you use in your attic. A 1/4" layer of the aerogel fabric is equal to roughly 6" of the glass wool.

Bat56

I put those Toasty Feet aerogel insoles in my MXZ-302s this winter and they are great. I think the coldest day we had this winter was around -20F and that keeps me on the bike for about an hour. My feel held up great - way better than last winter without these things. (I wear two merino wool socks, one "normal" against my skin and one Darn Tough Mountaineering.

AngrySaki

I used the inserts I bought yesterday, but it ended up being warmer than expected. I did about 3 hours in -10C with toe warmers and my feet only started getting cold near the end after I slowed down and took it easy. Normally my feet would have gotten cold 1-1.5 hours in, so they're definitely big improvement, but not a total solution for me in really cold weather.

modernjess

+1 on the toasty feet insoles.

I've had them for a few years now and they still work better than any other I've tried. I have no scientific data to back that up.
IMHO $15 is not an expensive upgrade and they are worth it