Winter Cycling - My quest for the ultimate winter cycling shoe

For me, the the most difficult thing about winter riding has been keeping my feet warm on cold extended rides. Of course I have found several solutions that work to keep my feet warm in varying degrees. But all the solutions that I have found so far have been wanting in some critical area of performance. The things that really kept my feet warm for long periods of time were heavy and so made the riding less enjoyable and reduced the distances I could ride. Seriously, it is not fun to be wearing 2-3 pound hiking boots on each foot when you are used to 12 ounce cycling shoes. Try riding at 80-90 rpm cadence for long periods with heavy boots on and the riding gets tiring quickly. The heavy hiking boots also bind at the ankle to some degree and of course if you want to use clipless pedals you are faced with the dilemma of drilling holes in the bottom of the soles and doing some custom sole work which can render the boots less usable for other things.

My present strategy is to use either a dedicated pair of winter cycling boots (Answer Kashmirs) with thick wool/acrylic socks or to use a layered method of neoprene sock/wool sock/oversized shoe/shoe cover. The Kashmirs are very comfortable but limited in how cold and how long I can ride with them. The layering method seems to have about the same coldness and time limits for me. I can ride for about 45 minutes down to 20-25 F then my feet will get cold.

There are several reasons why I believe that this is the case and I will detail some of the technical reasons why I think the typical winter cycling shoe strategies are not that good.

Anyway last year I came up with an idea that would be reasonably inexpensive to implement. But it would not be dirt cheap. I was however, too busy last year to work on the project but I think that I want to try to do it this year. And my plan is to document what I am doing here with pictures and explanations so that if someone else wants to try this method out they can try out my idea.

When you look at the technical requirements of what is necessary in a cold weather (below freezing) cycling shoe a few things become obvious. It is necessary that the shoe breath quite well but also block the wind well enough so that cold air does not rob the foot of heat. The shoe also needs to be insulated on all sides not just on the top since heat can just as easily be removed from the foot from the bottom. This is one of the major problems with the current crop of winter cycling shoes.

The shoe also needs to be as light as possible and not too bulky or it won't have enough clearance with the crank arms. And after a great deal of thought it seemed obvious to me that this combination of factors would be difficult to achieve with a single shoe. It would take a dual boot system to accomplish this. An inner one to support the foot and and outer one to insulate the structural inner shoe. It was while browsing at extreme mountaineering boots that I had this design idea.

So the project will consist of a light weight inner cycling shoe that is highly breathable. And to make things very easy, this just happens to be the property of nearly all road cycling shoes. Lightweight, stiff sole, breaths like crazy. But have you ever tried walking on ice with a road shoe with a cleat on. Not very fun and often dangerous.

The outer boot however does not need to be stiff or even heavy. It can be designed with sticky rough surface on the bottom so you can walk on snow and ice. Try to picture the concept of a superlight down bootie made a little less bulky and more form fitting with a road shoe inside and made just for cycling. Then you will get the general idea of what I am doing here.

I bought these Specialized road shoes last year specifically for this project. They were about 80 USD. They weight 12.2 ounces each and are 2 sizes over my normal size. They are just about perfect and I think that any lightweight cycling shoe could do here. Road shoes will be a little lighter and less bulky inside the outer boot but you could use any shoes you have on hand. My hope is that the outer boot will be warm enough that these will work with even non over-sized shoes.

Since part of the warmth equation is keeping blood flowing in the foot and especially the bottom of the foot the shoe should be as stiff as possible. A inexpensive road shoe like this is pretty stiff but I plan to enhance it. Both for the reason of increasing stiffness and to block off the holes that are created in the bottom of the sole. This will be the first step in my custom shoe process.

Here is the familiar bottom of the sole in a typical cycling shoe. In order to make the cleat adjustable the slots are built into the sole which allow cold air and water to penetrate. They also reduce the stiffness of the sole at the critical area of the cleat. This is especially a problem with SPD cleats which we will be using for various reasons which I will explain later. So my first goal in this project is to build a custom plate that will cover up these slots and holes and make the sole stiffer in this area. I want to do it without much weight penalty and there is a natural curvature of the sole so I think that I will use aluminum plate bent to form to the sole curvature and with a thin thermal barrier gasket of some kind of dense foam between the plate and the sole.

A rough sketch of the plate. I used another pair of cycling shoes with SPD cleats mounted to estimate the cleat hole placement since these plates will not allow for adjustment. But since I know my own needs I can dial the hole placement in the plate to the correct place. If I measured or estimated wrong then I will have to make another plate which shouldn't be all that hard. Just a little more work.

The rest of the project should be small petty cash items and the inner shoes will be the primary cost of the project. The next few days I will cad out the sketch and print an accurate pattern on the printer to make the part out of. Then I can place the paper pattern on the shoe first to see if my design is good. If anyone has any good ideas for a heat barrier gasket that will be cheap and easy to find I am open to suggestions.

I think some ultra high density closed cell foam might do the ticket. Like the stuff padding my calipers in the it's case.

closed cell foam made for wall insulation. might want some metal cleats/studs for the outer layer.

on a related note, have you considered doing a MTB shoe version of this?
mtb style pedals and cleats do a better job of expelling mud and snow than road versions. MTB shoes breath just as much, but have treads on them.

closed cell foam made for wall insulation. might want some metal cleats/studs for the outer layer.

on a related note, have you considered doing a MTB shoe version of this?
mtb style pedals and cleats do a better job of expelling mud and snow than road versions. MTB shoes breath just as much, but have treads on them.

There is no reason why a mountain bike shoe could not be used. But I think the road shoe will work better with the outer overboot that I will be making. Since most of my winter riding is on roads and bike paths the first version of this project will not have cleated bottoms or soles but will have some thin non skid rubber material.

gotcha

as with any over-boot design, I would try and keep it as single piece as possible since snow and rain do like to seep in through any joints.

One problem that I think all "clipless" shoes/boots have ( SPD etc ) is that you are "bolting" yourself to a steel or alloy pedal, thats gotta have bad effect on heat transfer. I have been meaning to get a set of PolarWrap's toasty feet aerogel insoles. I think these have problems for regular walking, the material tends to be brittle, but would suit stiff cycling shoes wonderfully. Anyone tried them?

One problem that I think all "clipless" shoes/boots have ( SPD etc ) is that you are "bolting" yourself to a steel or alloy pedal, thats gotta have bad effect on heat transfer. I have been meaning to get a set of PolarWrap's toasty feet aerogel insoles. I think these have problems for regular walking, the material tends to be brittle, but would suit stiff cycling shoes wonderfully. Anyone tried them?

Yes this is one of the big problems with clipless pedals. My approach will still have this problem but I hope to minimize the heat loss out the bottom of the foot by having the majority of the sole insulated with a rather thick closed cell foam. I'm shooting for .5-.75 inch thick high density foam under the sole. This will kind of have a moon boot effect on the looks but since when pedaling it should not interfere with anything. Using standard SPD pedals I will only need about a 1.5 - 2.0 inch square opening for the cleat to engage the pedal. This raised area under the sole will also make the system more walkable. Since you typically can't walk well in road shoes. Especially on slick snow and ice. I'm also hoping that the plate gasket may slow down heat loss to a small degree. But then again I am putting three additional bolts into the bottom of the sole which can transfer heat out of the sole as well. So this approach is probably sixes. But it will stiffen the sole more and block out the cold air and water spray from the big slots in the sole. I also think adding stiffness may help increase blood flow under the ball of the foot by spreading out the pedal force over a wider area of the sole.

http://lacemine29.blogspot.com/2007/11/warm-feet-are-happy-feet_17.html

Umm... cool ideas and such... but what about just wearing electric socks? http://www.thunderboltsocks.com/ (Just the first one I got when I googled.)

Or a cheaper version http://www.amazingsocks.com/web-pid-SPP2D356-Elder-Electric-Thermolite-Boot-Sock-item.htm

Umm... cool ideas and such... but what about just wearing electric socks? http://www.thunderboltsocks.com/ (Just the first one I got when I googled.)

Or a cheaper version http://www.amazingsocks.com/web-pid-SPP2D356-Elder-Electric-Thermolite-Boot-Sock-item.htm

Seems like this idea would be worth a try but I somehow have an aversion to relying on batteries every time I go out. I don't want to have to buy a new set of batteries for every ride. Nor do I want to run to the store before every ride to get them. Plus they are not environmentally friendly so I wish to keep my battery use to a minimum.

As for Mrbubbles link. I not sure I can believe it. Maybe if you have small feet. You would have to have your Lakes be 5-6 sizes over to get those felt liners in them. And if you already wear a 10 you are suddenly in sizes too large for them to stock. I have Answer Kashmirs 2 sizes over and I can't even put on my thickest wool socks with them. They are seriously thick these socks I have. Probably are 3/4 inch thick while laying on a flat surface. And these socks will compress a whole lot more than a felt liner would. So if the author of that link uses a size 15 Lake boot and his feet are 8.5 this is not a realistic method for a person with wide size 10 feet. I would need a 16-17 size shoe.

There is also another issue that you guys may not be considering. Performance. Keeping your feet warm is not difficult. What is difficult is doing it and maintaining light weight and a feel for the bike and pedal. When you have so many thicknesses of insulation between your foot and the structural part of the shoe you loose most of your pedaling effeciency as too much of the energy is lost in the compression of the insulation. That is why it requires a double boot system to accomplish what I am trying to do. I will only be wearing one medium thick wool sock to keep insulation compression to a minimum. Plus my system will be much more breathable. And probably warmer too.

I have gotten a little more work done on this project this weekend. I cut out the aluminum plates and mounted them without the insulating gasket to the shoes. They seem to work OK but I had to use somewhat longer screws than usual and the inside of the shoe seems to have a little raised area under the ball of my foot. It isn't too bad and I could ride with them like this but I think that they will improve a little when I add an insulating spacer. It will have to be no thicker than about 1/8 inch.

So far I have spent about $ 1.92 past the cost of the shoes. I had some small scraps of what must be close to 1/16 inch aluminum plate around so there was no cost there.

I also decided to use some cheap closed cell foam that I had around the house from a cheap sleeping mat. This is the kind that they sell for 5-6 dollars at the discount stores in the camping department. I cut out a shape that will end up being the size and shape for the bottom of the outer bootie. This foam pad will be an insulating member inside the bootie.

I think my first attempt at the outer bootie will be a relatively snug fitting and low loft design. Then I may make a higher loft more wind resistant design for even colder temperatures.

I have spent some time thinking about the problem of insulating the aluminum plate from the rest of the sole. One thing that seems like a better approach would be to make the plate out of fiberglass reinforced epoxy. The aluminum plate was a relatively easy method but unfortunately aluminum has a k value of thermal conductivity of around 250 depending on temperature. This makes it an extremely high quality conductor of heat which is exactly the opposite of what we want.

It seems that fiberglass is in the range of .04 and epoxy in the range of .35. So fiberglass reinforced epoxy is going to be very stiff and light and conduct a whole lot less heat out of the bottom of the shoe compared to aluminum. So it seems the better material. Although it will be harder to manufacture the plates it should not be too hard.

I think that I will get some good heavy woven fiberglass fabric and cut two or three layers from the pattern. Then I should be able to drape the bottom of the shoe with plastic wrap and soak the glass fiber cut outs in resin and lay them up together so they form the curve of the bottom of the shoe. I can make the plate as thick as I want. And still add a thin insulator of even lower K value if I want. I just need to find a way to hold the shoe in the correct position while the epoxy cures. I even have some general purpose epoxy around. Maybe even some fiberglass fabric.

Great looking project, I'll be keeping an eye on this one!!

Some thoughts on your fiber lay up. use a heavier plastic film (industrial garbage weight), and test with your resin to be sure that it doesn't burn through(exotherm temps can get pretty high). Now if you want to know about using foam coring, flocking, vac bagging and other tips, that is going to take more then the time that I have tonight. Heck, I could see a insulated, hole filling, cleat mounting sub-sole.

Now the CARBON FIBER FENDERS that me and a buddy are planning to make over the winter at work (government work, shhhh), should look sweet! I'm still collecting scraps of cloth (the waste, ohhh the waste) for the lay-up. Once we have enough, them the fun begins!!!!!

I have spent some time thinking about the problem of insulating the aluminum plate from the rest of the sole. One thing that seems like a better approach would be to make the plate out of fiberglass reinforced epoxy. The aluminum plate was a relatively easy method but unfortunately aluminum has a k value of thermal conductivity of around 250 depending on temperature. This makes it an extremely high quality conductor of heat which is exactly the opposite of what we want.

It seems that fiberglass is in the range of .04 and epoxy in the range of .35. So fiberglass reinforced epoxy is going to be very stiff and light and conduct a whole lot less heat out of the bottom of the shoe compared to aluminum. So it seems the better material. Although it will be harder to manufacture the plates it should not be too hard.

I think that I will get some good heavy woven fiberglass fabric and cut two or three layers from the pattern. Then I should be able to drape the bottom of the shoe with plastic wrap and soak the glass fiber cut outs in resin and lay them up together so they form the curve of the bottom of the shoe. I can make the plate as thick as I want. And still add a thin insulator of even lower K value if I want. I just need to find a way to hold the shoe in the correct position while the epoxy cures. I even have some general purpose epoxy around. Maybe even some fiberglass fabric.

IMHO, this is the crux of the matter-preventing the cold from seeping in through the contact between the pedal and the clip on the shoe.......interesting we have two parallel threads on winter shoes......

Buying a bike shoe that costs as much as a bike seems ridiculous to me (Lake).

I got a larger than normal bike shoe and use a Sorel boot liner as an insulator-we have a legendary discount store here in Maine-Mardens-picked up a pair for 10 bucks....Has worked great down to minus 20 deg F! I trimmed the top so as not to be much taller than the shoe.

Also from my years of bc skiing I use a vapor barrier-goretex sock........

Thus, I am able to continue to use my clipless pedals and keep my feet warm.........

Hands and feet have been the challenge to keep warm........Kinco gloves for the hands and this combo for the feet and I am good to go.........

Great looking project, I'll be keeping an eye on this one!!

Some thoughts on your fiber lay up. use a heavier plastic film (industrial garbage weight), and test with your resin to be sure that it doesn't burn through(exotherm temps can get pretty high). Now if you want to know about using foam coring, flocking, vac bagging and other tips, that is going to take more then the time that I have tonight. Heck, I could see a insulated, hole filling, cleat mounting sub-sole.

Ya, this can really get the design ideas flowing. But my primary goal is to keep it easy enough to make that anyone can do it. I will keep the epoxy heat problem in mind. I have this inexpensive cheap general purpose epoxy that should work. It only gets about 130-150 degrees when it cures. It's probably not the ultimate epoxy formula for this but it should work.

Here's my idea for the ultimate plate. Made from carbon fiber and epoxy. It has a hollow honeycomb core to make it ultra stiff and light and is formed under vacuum so the plate acts like a vacuum flask insulator in addition to being stiff and light. However, this would increase the thickness to at least 3/8 inch I would think.

Just an update,

Because I want these booties to be good enough fitting that they both look OK and don't interfere with crank arms too much I need a pretty accurate pattern. So I'm going to be spending the next bit of time on this project doing a 3d model of the shoe and booties to actual size. Even down to the thickness of the insulating material used. I'm thinking that the first prototype will use a breathable shell of powershield with an insulating layer of stretchable polar fleece. And some kind of a thin textured rubber/vinyl sole material.

I just wanted to bump this thread to let everyone know that I am moving along with this project even though I am going at a slow pace. I started to do some 3D modeling of the outer boot cover. So far I have only placed some scaled pictures and the foam sole in the model. Once I create the surfaces for the outer boot pattern I will break them into two shapes and flatten them out so that I can print out an accurately scaled flat pattern.

Here's a screen shot. I hope to get a lot more done on these over the christmas holidays.

One problem that I think all "clipless" shoes/boots have ( SPD etc ) is that you are "bolting" yourself to a steel or alloy pedal, thats gotta have bad effect on heat transfer. I have been meaning to get a set of PolarWrap's toasty feet aerogel insoles. I think these have problems for regular walking, the material tends to be brittle, but would suit stiff cycling shoes wonderfully. Anyone tried them?

Yes. I have the original style. I and my riding buddies think they allow you to ride in 10 degree Fahrenheit colder conditions comfortably compared to not using them. My riding buddies got dedicated winter shoes, Lakes I believe, and they use the Toasty Feet in them.

I was on the website recently and they have a thinner insole that I had not seen before. I do not know how it compares to the thicker one but I could use the extra room since I did not buy my road shoes with winter cycling in mind.

This weekend I have done a little modeling and come up with a pattern. Here is a screen shot of the pattern. Is was flattened from the 3D model in Rhino and then brought into AutoCAD for scaling and saving as a DWG file. The 3D model was not exactly perfect but I did not want to spend anymore time with it on this first prototype. It should fit well enough with the stretchy material the outer boot will be made of.

The pattern is designed so that there are no seams except where the upper meets the lower sole. This pattern has no seam allowances added. So they will need to be added and just how much will depend on the method of enclosure and how I do the elastic around the lower leg. At this point, my intention is to have one long velcro strip on the outside as the enclosure mechanism. I want them easy to get on and off.

If you want a copy of this pattern in DWG file format let me know and I will e-mail it to you. You can scale the pattern in any CAD system to your size by making an accurate tracing of the sole of your shoe and measuring around the outer perimeter. Then measure the outer long curve on the pattern model and interrogate it's properties to find it's length. It will need to be the same length as the outer perimeter of the sole. With these two numbers you can calculate a scaling factor. Then you can print at 1:1 to a plotter or printer to make the pattern. Then you will need to add the seam allowances when you cut out the material.

I ended up having to bring the DWG file into another CAD file viewer for printing since AutoCAD cannot tile the output from a small printer. I do not have access to a large format printer without having to pay for it so I decided to go this route. It could be done at the local Kinko's for a couple of bucks if necessary. There are several shareware utilities that can do the tile printing with good enough accuracy. I used ABviewer.

Well, I'm off to the fabric/craft store to see if I can find some fabric scraps that will work well enough without having to go with the expensive outdoor specialty fabrics. At least for a first prototype.

Hezz,

how see very willing to make your own, but lightweight winter cycling footwear is commercially available.

Showers Pass has a fullfoot overshoe with heavy rubber tread coming out spring 2009. see it in their on-line catalog.

using Outdoor Research Mukluks as overshoes are rideable in and are very little extra weight, and would just need a reinforcement in the sole and topclip area to become very approp for cycling.

I used to ride in USAF mukluks, either with the felt liner or over a pair of streetshoes and wool socks. These USAF Mukluks were the bomb for riding hardcore Upper Peninsula winters.

picture of Outdoor Research Mukluks below, on a winter bike-camping trip, pulled over my cycling shoes.

I see, reading back more closely that you are trying to create a winter clipless shoe system superior to what is presently available. hmm... I would use a cycling sandal as the base, add some closed cell footbed, a felted upper, then gluefit your fabric of choice around the sandal as an upper. Maybe just glue some OR mukluks onto a sandal... done and done.

manufacturing a sole stiff enough for cycling at home? well, a hand carved wood midsole might be the answer.

Hi Bek,

Good ideas all. Of course you are correct in that I am trying to outdo what these other pre-made solutions can do. Both in terms of warmth and performance. I do like the scandal idea though and I even thought of going in that direction. But I had already purchased these shoes last year. Since I had intended to do this last year but got sidetracked with other things.

I'm hoping to see someone try the scandal approach in a more serious way. But one of the reasons that I rejected that approach is because my feet are very sensitive to the SPD pedal pressure and only the hardcore cycling shoes are stiff enough to suit me.

I do think that I have found the ultimate material for the sole plate insulators though.

Update,

I mentioned in the last post that I have found what I think will be some good materials for resisting the transfer of heat out of the sole of the shoe. I read in another thread about these aerogel insoles which are reasonably priced.

http://workingperson.com/products/22_95/1/4426/PolarWrap_Insoles:_Mens_Toasty_Feet_Aspen_Aerogel_Insoles_TFM.html

I then read a review that said that they really did help keep your foot warmer and that they wear for a reasonable amount of time. So I did some research on aerogels since I have heard of them before as they are used in the audio field to make speaker cones out of. It turns out that this family of materials have the highest insulation value per unit thickness of any material.

So I decided that they would make good foot bed liners in my winter cycling shoe project. I then did some more research and found a company that makes industrial aerogel materials for insulation of pipes and other things.

http://www.aerogel.com/products/overview.html

I think the Pyrogel 2250 would be just about the most perfect thing to make an insulator gasket out of and place under the glassfiber/epoxy plate. So I'm hoping that I can get a small sample from Aspen aerogels of this material to use. I think this approach of using a glassfiber compostie plate and aerogel insulator and aerogel insoles will stop a lot of the heat transfer out of the shoe from the pedal. At least that is my hope.

Update,

Today I received a package from Outdoor Wilderness Products with the material for the boot covers. I also bought a few things at Kirkhams AAA so now I have enough materials to make two pair of outer boot covers. I have two different types of material for the bottom walking surface to try out. The only thing that I lack is some polar fleece remnants, which I can get at the local craft/fabric store for 4 dollars, for the insulation layer. So far, I have spent about 31 dollars on the materials.

Since I don't have a commercial sewing machine I have come up with a plan that I think will work to make these things. The part that I will have trouble with is the sole. But I think that I can sew everything that I need to except the sole either with the machine I have or by hand. What I want to do with the sole is cut out a piece of plywood the same shape as the sole and use it as a form to work on. The method that I envision is to cut out a piece of cordura the same shape as the sole and sew the upper to this and then stretch it around the plywood form. Then I will use Shoe Goo or some kind of appropriate adhesive to glue the final outer sole material to the cordura sole. This should make a kind of waterproof barrier on the bottom. So that small amounts of water which might be walked on won't soak in as much through the sole.

http://lacemine29.blogspot.com/2007/11/warm-feet-are-happy-feet_17.html

Curiak's system is the bomb but of course only works because his feet are 6 sizes smaller than the largest Lake Cycling boot.

What is not explored here is starting with a winter cycling boot and doing the same thing you do with cycling SHOES to extend their temperature range. What about overboots? The thing I do to increase my temperature range is wear Outdoor Research Gaters. This effectively elminates heat loss from the cuff and turns the entire lower leg into a heater. The cost though is that you can no longer get at laces and straps for shoe adjustment.

Answer Kashmirs (2 sizes too big) down to about 15 degrees using using gaters with double wool socks on the inside. Haven't tried overshooes over the boots yet. But it has to help.

BTW, I noticed that Lake is now selling a "boot" style boot.

Looks comfy to me and it's only $170.

Curiak's system is the bomb but of course only works because his feet are 6 sizes smaller than the largest Lake Cycling boot.

What is not explored here is starting with a winter cycling boot and doing the same thing you do with cycling SHOES to extend their temperature range. What about overboots? The thing I do to increase my temperature range is wear Outdoor Research Gaters. This effectively elminates heat loss from the cuff and turns the entire lower leg into a heater. The cost though is that you can no longer get at laces and straps for shoe adjustment.

Answer Kashmirs (2 sizes too big) down to about 15 degrees using using gaters with double wool socks on the inside. Haven't tried overshooes over the boots yet. But it has to help.

BTW, I noticed that Lake is now selling a "boot" style boot.

Looks comfy to me and it's only $170.

The problem with the winter cycling boot approach is that the current crop of winter cycling boots are not breathable enough. They are all lined with neoprene. So they trap too much moisture to be useful for more than an hour or so in colder temperatures. So you would in all actuality be better off starting with a super light breathable climbing shoe or maybe something like those new Lake boots if they are breathable. However, there seems to be a new crop of winter cycling boots models that have come out new this year that seem to use gore-tex instead of neoprene and seem to me that they might be breathable enough as a place to start. There are new shoes from Shimano and Pearl Izumi, plus the Northwaves may be breathable.

However, bear in mind that I am trying to build a system that is both warm and performance oriented. Meaning that it will be light and responsive. And easier to get on and off without having to layer so many socks and other layers. It is not intended to be something so rugged that you could walk in it for miles. For something like an alaska expedition you would need something like the Brooks Ranger overboot over a lightweight climbing boot. Or if your feet were small enough you could use Curiak's method. I even think you could use a Brooks Ranger overboot over a regular cycling shoe but this will add quite a bit of weight.

Update,

I got most of the material cut out. Nothing exciting enough to take a picture of. The sewing part is going to take some doing. I've got a Powershield like material for the outer and a lightweight stretch fleece for the lining. But now I am considering putting a middle insulating layer of thinsulate or cheap polyester batting. I don't want them too puffy but I want them to be warm. I think something like 1/4 - 1/2 inch thick faced polyester insulation in between the outer shell and lining may work. Something that can compress easily so if it interferes with the crank arm turning it will just compress without creating much friction. I'll post a picture as soon as I have something to look at.

Meanwhile, I think I am going to have to get some different epoxy resin and hardner since the stuff I had I just used for another project and I don't think it will work for the shoe plate. It didn't seem to have the right consistency to "wet" a piece of fiberglass clothe. It was too thick and bubbling. I will need some kind of epoxy resin that behaves more like casting resin than glue.

Here is my idea for making the fiberglass/epoxy sole plates.

I have made these two impressions of the front of the sole in these pie tins filled with concrete. The molds don't look all that great but I don't need super high accuracy. I will have to do a little smoothing of the molds.

What I am going to do is lay up the fiberglass and epoxy on the mold and then vacuum bag the mold using a cheap method to get the layup to take the curved form of the sole. This will also make the plate have a more uniform density and be more uniform that what I could do myself.

The vacuum pump will be made from and old bike pump or small car air compressor.

Interesting project! Have you considered phenolic spacers for the cleat/foot barrier? Phenolic plastics are often used as heat barriers between engine parts. I think they can reduce conductive heat transfer to a minimum, and would likely be more durable and easier to acquire than aerogel.

Good idea,

If an aerogel sample proves too difficult or costly I will look at some phenolic resin. However, I know that I can obtain at least an aerogel insole for the inside of the shoe. I am almost tempted to think that what I am doing is overkill. I think the overboot will keep my foot warm enough for the conditions that I normally ride in.

However, come to think of it. The plate spacer needs to be a softer kind of material so that it will create a seal to keep out any cold air or water from entering the bottom of the sole. And ideally it should not be too thick so that it won't absorb too much energy from pedaling. All of the phenolic composites that I have seen are rigid types of plastic. I wonder if a linen/phenolic plate would be even more stiff than the fiberglass/epoxy. Maybe, but I have decided that the project must be buildable from easy to obtain parts and materials. The fiberglass epoxy should be just about the easiest and cheapest low K material plate that I can think of.

I was mixing some epoxy for another project and I thought that I would try to make some quick gravity layups from the cement molds of my cycling shoes. I worked really fast because I had already mixed up the epoxy so the work was a little bit sloppy. I was not convinced that this epoxy would work. It is a very slow setting kind of general purpose epoxy that takes 24 hours to fully cure.

But it has also allowed me more time to kind of message these things into shape. I first started by cutting a ziplock bag so I had a single layer of plastic. I was out of plastic food wrap so I used this. I then layed the plastic sheet on the mold and sprayed it with PAM as a release agent.

Then I poured some of the resin in the mold and quickly cut out three layers of fiberglass cloth to shape. Using a plastic knife I worked the resin into the three layers of fiberglass cloth and tried to get as much of the resin out of the mold as I could. I got one of the plate layups somewhat misaligned but I will be able to trim it later.

In retrospect I could have taken more time since the epoxy was still viscous after 1 hour. I ended up with things looking like this.

After curing overnight ( about 9 hours) the plates were firm enough to be removed from the mold and the plastic peeled right off. The plates were still soft enough to trim them with a pair of good strong scissors. I then taped them to the shoes in hopes that they will retain the proper curve as they continue to harden. Hopefully they will get hard enough to be useful.