Dr. Sole has pulled off one helluva trick: they’ve made shoe and boot outsoles fun.

Unafraid to go up against giants like Vibram, the Taiwanese brand has established itself as a top-tier solemaker while constantly finding ways to surprise and delight us. Innovative sole formulas that include ingredients like burlap or coffee grounds. Now-iconic designs and compounds that have been adopted by everyone from Viberg to Sagara. Adorable (and functional!) tributes to Formosan black bears

We asked Dr. Sole founder Chao-Yung Lin to take us on a deep dive into the company’s advent and evolution into a niche sole-making powerhouse, and he was more than game. We talked so much, in fact, that we had to split up our interview into two parts.

In the first half of our conversation, Lin recalls how his love of vintage boots and a couple hundred deadstock Cat’s Paw heels inspired him to launch Dr. Sole in 2011. Lin’s end-to-end breakdown of the design, development, and manufacturing processes necessary to get a new sole off the ground is fascinating—and his commitment to bring greener methods to the industry is nothing short of inspiring. And of course we had to have a little fun cataloging some of the more unusual sole designs that haven’t made the cut.

Stay tuned for Part Two, where we’ll delve into Dr. Sole’s cobbling service Bench-Re-Built, as well as their growing Pioneer line of footwear.

Chao-Yung Lin

Chao-Yung Lin (middle)

Josh: I understand that before Dr. Sole came about, you spent some time earning a master’s degree in Colorado. What were you studying? And how did you eventually decide that making soles was something you wanted to do?

Lin: From 2009 to 2011, I studied at University of Denver (DU) to earn my master degree in Marketing. The reason why I chose to go to Colorado was simple: the mountains. I never regretted my decision as I went to so many gorgeous landscapes and national parks, and got to the top of several 14ers in Colorado in my Danners or vintage Irish Setter hiking boots. One thing I think is worthy of bragging about is that I traveled to all 50 states of the USA within these two years.

My major was marketing, specializing in integrated marketing communication. I was thinking of beginning my career in the field of “green marketing” or getting a job in an environment-preservation-related corporation. I care about environmental issues. I volunteered at environmental preservation NGOs, and I truly believed that “green marketing” was something I wanted as a career.

However, life never goes as you plan. My wife Betty and I went to the same master’s program. When we were about to finish, her father Johnny had a stroke and hoped Betty would go back to accompany him during his late days of life. Johnny began his career as an apprentice at a rubber sole factory in Taipei, Taiwan when he was 16 years old and owned a sole factory specialized in rubber soles in Southern China since 1992. He also hoped Betty and I could work for him at the factory.

This was not what I planned, but I ended up taking the offer. 

How did you originally get interested in footwear?

I have been fond of footwear since high school. I have been buying leather boots and collecting vintage soles and heels, such as Cat’s Paw, Biltrite, and O’Sullivan’s for a long time. When I was still in the States, I enjoyed visiting flea markets to hunt for vintage clothing and leather boots. I browse eBay all the time. Once I bought some new old stock Cat’s Paw heels from an eBay seller, and out of curiosity, I asked the seller if they had more. 

It turned out that they were selling the inventory for a closed shoe repair shop. I ended up buying all the stock heels and soles from the seller, around 300 pairs or so. I didn’t know why I bought such a large quantity at that time, but they helped a lot when the Dr. Sole brand was started. Before leather boots, I was a sneaker guy who bought lots of Air Jordans and some rare models. I was so into sneakers that my first job after my college was at a sneaker shop. 

dr sole green supergrip heels

Very cool. But, back to how this all got started with the sole factory…

Betty told me that I could have the chance to help her father operate the factory in a greener way. I was totally persuaded, so we moved to China right after we finished our master program in DU.

Since Johnny’s factory had been providing outsoles for many international footwear brands including Clarks—about 90% of the soles were made for international brands—he wanted us to join the sales department at the factory due to our English ability. Betty also speaks fluent Japanese. So, this was how I stepped into the sole-making industry. 

Both Betty and I were new to this industry, so we had much to learn, such as the sole-manufacturing procedures step by step, the differences in various rubber compounds, the mold-making, and so on. For a shoe enthusiast like me, this was an exciting time.

It seemed that establishing a brand was a dream for every manufacturer who had been making things for other brands. Johnny was no exception. He had come up with a brand name and registered it as a trademark several years earlier—Dr. Sole—which was Johnny’s nickname. Since he had been in the industry for a long time, he knew nearly everything about rubber soles. He not only owned the factory, but was the head of the R&D department. He could duplicate nearly any rubber compound as long as he saw and touched them. 

He was also keen on creating something new. The factory owns three product patents in China, all developed by Johnny. However, it’s also every manufacturer’s nightmare when it comes to brand management and all the marketing aspects. 

Johnny and his team knew nothing about operating a brand and the factory was just too busy fulfilling the orders to start it. The brand was nearly forgotten until I found it. I thought to myself, why not activate the Dr. Sole brand to step into the game I am passionate about: work boots. The space had been dominated by Vibram for several decades, and it could be an opportunity for a newcomer with a strong manufacturing background to create some ripples in the water. I proposed the project to Johnny and he was quite excited about it. In December 2011 I revived the Dr. Sole brand.

Did you also decide to go with “Dr. Sole” as a tribute to Johnny?

In the beginning, I just thought it was a good name for a brand and I didn’t think of using the name as a tribute to Johnny. After all, Johnny was more like a scientist or a maker; all he wanted to do was to make good rubber soles. He knew nothing about heritage work boots or anything related to how people see Dr. Sole today.

However, when Johnny passed away in 2016 right before my brick and mortar shop in Taipei opened, I changed my mind. Now I would say Dr. Sole is Johnny’s legacy and a tribute to his contribution and endeavors in the industry and the family. I believe he would be proud of us if he could see what we’ve achieved today.

dr sole landis k

I hope that he would be proud. So, how did things start off for Dr. Sole?

In the beginning, I designed 10 styles of soles/heels, including our all-time best sellers—Super-Grip half sole and Raw Cord full soles—based on my sole archive. But I needed to demonstrate them with some boots, so I sent mine to a local cobbler to have them resoled with the new soles/heels. Then I posted these resoled boots on the Superdenim forum of Superfuture, and I was super glad most posts got positive feedback. 

But no one really asked me how to purchase the soles at first. Then I received a message from Kiya of Self Edge saying that he was interested in buying the soles to use on their collaboration boots with ACE Boots (which is unfortunately out of business now). I couldn’t express how excited I was when I read the message—I must admit I even yelled and screamed. ACE Boots ordered a small quantity of samples, which was Dr. Sole’s first order. Though Self Edge and ACE Boots didn’t place further orders, their support meant a lot to me and Dr. Sole. 

dr sole cork sole

Dr. Sole has become more and more recognized ever since. I kept sharing the resole results, and more and more people and shoe repair shops worldwide sent me emails for ordering the soles. Most of them were small orders, but I was still happy. Dr. Sole’s first peak was when Viberg used our Raw Cord soles on its Boondocker service boots. We also worked with Wesco to produce its 100 Anniversary soles and heels in 2018. Today, we’ve sold our soles and heels to more than 30 countries.

You mentioned Vibram’s dominance in the sole industry. Do you see Dr. Sole as being a direct competitor to Vibram?

No, not even close. We are too small to compare to Vibram. But I like a metaphor that a customer once said to me: Vibram is like Coke and everyone likes it. Dr. Sole is just like Dr. Pepper. Not everyone likes it, but when you do, you are obsessed with it. 

dr sole strider

Very apt! What have the challenges been with learning how to manage and work with a sole factory? Were you able to find ways to make the facilities more environmentally friendly?

There are many procedures to make a rubber sole: from the mold-making, compound formula, compound-mixing, sole-making, to the finishing, and so on. It involves many professional categories, such as design, chemistry, physics, and craftsmanship. It takes years to master any single procedure.

During my short stay in the factory, I could only learn the basic theories about every step, but they were helpful for me while designing the soles. One important thing while designing the potential sole/heel is knowing what one can and cannot do. For example, we cannot mix any materials, such as cork or cord, into a sponge rubber compound that is used to make cushion wedge soles. Knowing the limits and boundaries is very crucial.

Dr Sole Cushion Sportsman

But sometimes it’s also important to push the limit. It’s a common problem for any manufacturer: they tend to make something that they get used to. Sometimes when I presented an idea that I took from my vintage sole archive or an old print ad, and asked them if it’s doable or not, the first reaction was always “No.” I needed to show them that it had been done many decades ago. Persuasion is always prior to discussion. Simply put, communication was the most challenging part.

As for the green actions we’ve made for the past years, the factory has updated many facilities to catch up with stricter environmental regulations. For example, we’ve changed the power supply from coal burning—yes, very old school—to biofuel. It cannot be 100% green or environmentally friendly as we still produce a certain amount of waste and emit CO2. Besides, most of the rubber compounds we use are from petroleum products. But we are one of the very few sole factories in Southern China that pass all the environmental regulations.

If I named one thing that’s had the biggest effect, it would be adding recycled materials into the rubber compounds. When I just landed the factory in 2011, it was almost a taboo in the sole-making industry. It’s an open secret and has been done very often as sometimes it is necessary, but no factory would say it openly, as it would be viewed as a bad manufacturer who tried to save costs and make poor products.

I tried to convince them that we should indicate the percentage of the recycled materials that we’ve added into the compounds. It is totally a positive thing to do if the functionality and performance are not affected. Of course, they thought I was crazy. Then I proposed to make a compound that contains 30% of recycled rubber waste in various colors. The product looked extraordinary in a good way. Then some customers requested to use the same compounds when they saw the sample in the showroom. They chose them not just because they looked great, but also because they knew it contained recycled materials. The factory gradually took a more positive attitude toward the recycled materials, and became willing to introduce some.

dr sole tumaz blueprint

Can you explain all the steps that go into designing and then producing a sole?

The first step is design. I always hand-draw the design draft of the potential sole and heel. As I mentioned, most inspirations are from my sole archive: an old sole on some vintage boots, or even an old print ad. Then I talk to our mold-making department to evaluate if the design is practical. We make modifications on the drafts when we need to.

Then the mold-making department will draw me a mold draft with all the details and dimensions. The information on the mold drafts is very precise, and we can easily find some modifications that we missed on the hand-drawn draft. When the draft is confirmed, then we will move to the next step: mold making.

There are several ways to make the pattern and tread on the mold, depending on the design. Some patterns can only be made by using a CNC milling machine and some can only be achieved by hand stamping. It requires lots of craftsmanship to make a mold. For me, mold-making is equivalent to making an artwork.

dr sole supergrip mold

When the mold is done, we will begin the sole-making. Simply put, it is very similar to baking a cake. Precision is everything.

The sole-making begins with making the rubber compounds. Every compound has its own formula. The ratio of each ingredient that makes the compound cannot be adjusted randomly.  A small change in the ratio could lead to a big difference in the final product. In this stage, the “mixer” takes the ingredients of an exact amount based on the formula, and mixes them all together with a roller mixer. The coloring is also done here. Like the ingredients, the dye is also controlled very precisely, so every batch could have nearly the same color. For example, it is very difficult to keep every batch of the off-white compound the same color, as any slight change could make it darker or lighter. 

When the compound is ready, it’s time to “cook” it. The “baker” puts the compound inside the cavity of the mold, and heats the mold for 10 or more minutes depending on the thickness of the sole/heel. The thicker the sole is, the longer it takes.

The weight of the compounds matters at this stage. When making the first test sample, the baker puts more compounds than the estimated amount into the mold. When the sole is cooked, he/she will trim the excess. Then the baker will weigh the sole. When the exact weight is obtained, he/she will put the exact amount of the compound every time he/she cooks the sole to avoid the potential waste.

How long does it usually take to go from conceptualizing to manufacturing a sole?

It might take years to make a new style; for example, our Tumaz lug sole. But the shortest time we’ve encountered was less than three weeks from the draft to the final product. Usually, the time to design and draw the mold draft determines how long it will take to get the sole done.

dr sole tumaz

What inspires your more unique soles, such as the Burlap half sole and heel, or the Strider coffee-filled sole?

The Burlap soles were inspired by an old product that I saw at Johnny’s showroom. They used to make rubber sheets with the burlap fabric embedded at the surface. I remember Johnny told me that they had been making something like this for decades so it was in fact a very common product. But the first time I saw this idea, my mind was so blown. Then I decided to use this on Dr. Sole’s half sole and heel.

As for the coffee-filled compound, the idea suddenly came to mind when I purchased coffee at a local coffee shop. I saw the owner collect the coffee ground waste and re-use the waste for multiple purposes, e.g., fertilizer, cigarette ashes, air freshener for the refrigerator, and so on. So I thought, why not combine the coffee ground waste into the rubber compound? 

It did create some buzz when it was launched. However, since the coffee ground waste cannot be stored for a long time (unlike the cork and cord) and it gets moldy easily when the temperature and humidity are not controlled well, it is very difficult to collect enough coffee grounds for whenever we need it. So, we decided to discontinue it as a regular product, but we still take made-to-order for the soles/heels in the coffee-filled compound.

dr sole burlap

Are there other sole compounds and/or designs that you’ve tried which didn’t work out the way you expected? Or perhaps ones that you’re working on but haven’t quite perfected yet?

We’ve tried many compounds that end up not working. For example, we made a compound with pulverized oyster shells. The oyster shell shows different colors under different lights. However, it was terminated due to the difficulty in sourcing and storing the oyster shell. We also made some rubber compounds that will change the color under sunshine (UV reactive). Another interesting one is the transparent compound, which is fascinating because the shank and cork filler can still be seen.

Also, I do want to improve our cushion rubber compound used to make #3060 and #3070. For me, they are the most comfortable rubber compound for outsoles. However, the common issue of blown rubber compounds is that they might wear fast. So I really want to enhance the durability while still retaining the comfort of it.

Dr. Sole Half Sole Off White

What are some of the ways you’ve used customer feedback in developing your soles to meet market needs?

We’d been asked when we would have thinner full soles and thinner heel caps by our customers, especially the cobblers in the States and the shoemakers in Indonesia. Our Super-grip full soles and half heels are the responses to their requests.

When I was designing the #1230 Super-grip half heels, I made some adjustments based on our experiences on #1100 whole heels. I reduced the nail holes from 13 to 11 on a single heel cap because I realized there is no need to use that many nails to fasten the heel. Besides that, I also moved the nail holes toward the center a little bit. By doing this, the nails won’t pop up to the heel base easily when we are using longer nails.

Now that you’ve recently unveiled the Tumaz, what kinds of soles are you working on making next?

The next product could possibly be the sports heels—something like the King “B” heels. We have a similar product in our product line, the Trooper’s heel, but it would be slightly thinner than that. This style is difficult to get on the market. If I cannot find it, why not just make it?

A new, more streamlined cushion wedge sole is also undergoing development, inspired by running shoes. This might take longer, but I really want to make it work.

Stay tuned for Part Two of our interview with Lin from Dr. Sole…