Work boots are much more complex than people might think. There is a lot that goes into them to make them so functional in the workplace.
Such as waterproofing, durability, abrasion resistance, oil-and-chemical resistance, breathability, comfort, support, etc, etc.
There are many layers and components that make up the boot to assist with each need.
One of those components helps to deal with the last point just mentioned. Support. And it is the shank that focuses on this.
This article will address the differences between TPU (Thermoplastic polyurethane) shanks and steel shanks. We’ll explain what they are and what they’re needed for.
What is a shank in work boots?
Shanks are thin rectangular strips of material that help to spread the load of your weight and spread upwards pressure from objects on the ground, which helps to maintain balance on rocky or uneven terrain.
They also help to preserve the shape of the boots.
By doing this they offer arch support, which in turn helps the calves, knees, and even the back.
As already stated, work boots consist of many layers. Shanks rest nicely between the insoles and outsoles of the boots. Usually between the balls and heels of the feet.
During manufacturing, the upper and insole is made. Then they glue and/or tack the shank into the insole and attach the outsole over it.
Standard half shanks usually come in regular boots, if they have them at all. Whereas, heavy-duty boots usually have three-quarter or full length shanks for optimum support.
If, for example, you tread on big stones or sharp rocks, the shank will help prevent the object from digging into the bottom of your foot when under your full weight.
This makes them very popular with mountaineers and forestry-related work and people doing heavy-duty work in general.
TPU (Thermoplastic Polyurethane) shank
TPU is a type of plastic that can be found in many many products, due to its flexibility, oil-and-abrasion resistance, durability, strength, and lightness.
These points make it ideal for the outsoles of boots, running shoes, and other footwear designed for activities that need a lot of support and stability.
Similarly, TPU is great for work boot shanks. The blend of flexibility and toughness offers high puncture resistance and decent arch support. It also doesn’t get affected by low temperatures, making it perfect in the winter.
Being a plastic, TPU doesn’t set off metal detectors. This makes it perfect for people working in places like airports. Or passengers who choose to wear work boots through airport checks.
You might think that work boots are too cumbersome to wear on flights. This may be true in some cases.
But an advantage of TPU is that it’s lightweight, which is why it’s sometimes favored in jobs involving light duties. Or even jobs involving lots of kneeling and bending as is the case with mechanics for example.
Although TPU shanks aren’t as tough as steel shanks, they are cheaper.
And although not affected by extreme cold, one downside to TPU is that it might not withstand high temperatures compared to materials like Vibram. It won’t conduct the heat like steel would, but might melt.
Here are some pros and cons of the TPU shanks
PROS
- Lightweight
- Cheaper than steel
- Flexible
- Durable
- Won’t set off metal detectors
- Resistant to low temperatures
CONS
- Not as tough as steel
- Might not withstand high temperatures
Steel shank
Steel shanks are the toughest and most traditional of all the shanks. Although they’re the heaviest, they’re still only thin plates that can flex and contour.
Objects from below the feet are less likely to penetrate the sole and cause pain through steel shanks, which makes them ideal for the most heavy-duty tasks.
The arches and heels won’t bruise or ache that easily. So stamping your weight on digging tools, climbing and resting on ladder rungs if you’re an arborist or a lineman, or even hiking long distances can be done with relative comfort and little damage to your feet.
However, steel shanks do set off metal detectors, so if you plan on battling your way through airports and wearing the boots on a plane, you might want to bear this in mind.
Taking your boots off and putting them in that little tray while being checked might be time-consuming.
Also, steel gets affected by temperature. It conducts heat. So the shanks could make your feet warmer on really hot days.
Likewise, they could conduct the cold. But it’s most likely not to be a problem because of the heat trapped in the boots from your feet.
If the steel shank gets exposed to water, there is a chance that it would rust over time. This isn’t very likely, because of the measures the manufacturers make these days to keep water out.
Even sweat could be a factor. But most decent work boots have enough breathability and moisture-wicking to deal with that moisture.
These drawbacks are a minor cost, considering the benefits steel shanks give.
Here are some pros and cons of the steel shanks
PROS
- Very strong
- Durable
- Good puncture resistance
CONS
- Conducts cold and heat easily
- Sets off metal detectors
- Might rust over time
Last words on this TPU vs steel shank comparison
You should now have a clear understanding of what work boot shanks are, and the differences between steel and TPU ones.
We hope you can use this information to decide which is best for you, depending on your occupation or activities you like to do.
To give you examples, firefighters or high voltage cable workers might not choose to use steel shanks, because of the conductivity of heat and electricity.
Saying that though, firefighting boots, under NFPA standards are built to be resistant to extreme heat. And likewise, most premium boots will have electrical hazard resistance meeting ASTM standards.
On the flip-side, a groundworker or mountaineer might prefer the steel shanks because of the optimum arch support and puncture resistance they offer.
As always, you should do your research when buying work boots.
Check what material the shanks are, and what size. Check if the outsoles are heat-resistant or electrical hazard-resistant. These factors should counteract the conductivity of steel shanks.
Also, check the heat resistance of boots with TPU shanks. You certainly don’t want them melting
We hope you’ve found this article useful. If you have any questions or would like to add any information or experiences you’ve found useful, feel free to contact us. We would love your input.
Team Members Working On This Page
Jimmy Webb – Writer And Researcher
Hey, Jimmy here. I’m one of the researchers and writers here at BestForMyFeet.com. I’ve been wearing work boots all my life working as a forklift driver, landscaper, groundworker, and now as a tower crane operator so I know a few things about footwear and footcare in general. I’m also working on my first novel. So writing IS my passion. When I’m not writing I love to spend time with my wife, two children, and furball.
Victor Adrian – Editor And Webmaster
Construction Professional, driver, crane operator, cleaner, head chef … these are just some of the jobs I did in the past. Working in all these different environments taught me that having good footwear to protect your feet from different dangers at work IS PARAMOUNT for any worker! On this website, I aim to share all my knowledge and personal experience in dealing with different footwear and foot care issues, and hopefully, you can get something out of it. Enjoy!
