Mountain Bike Tires Threads Per Inch (TPI)

You might consider your mountain bike tires good until they go flat. There are some important features associated with their overall construction.

These features allow the tire to be stronger and protect the inner tube more effectively. Right under the rubber tread of the tires, there is a structure which is known as casing. It is made of nylon threads and they are call it TPI or threads per inch.

The most common features are nylon fabric coated with rubber for the required fabric thickness. These fibers are aligned at an angle of 45 degrees to your tire bead.

Multiple layers are aligned with alternating directions. These additional materials are to increase the stiffness and durability of your tire. These layers also provide them more rolling efficiency and make them lighter.

Importance and Function of TPI

Most people think the rubber of a mountain bike tire is its most important part, but the reality is quite contrary. Its bead, the woven casing between the tire edges, and the tire edges are essentially the nuts and bolts of your mountain bike tire.

A structure can’t hold its ground without these essentials. This was mentioned by Jayme Otto, a racer and a Bicycling editor in the 1960s, the time when these casings were made of cotton canvas.

Nylon has better tensile strength than cotton. High-quality mountain bikes tires also feature Kevlar which is a lightweight yet strong fiber. These perpendicular casings have thread layers and are measured in TPI (Threads Per Square Inch).

According to Ian Dille, an ex-pro cyclist, a larger thread will have stiffer casing with lower TPI. A casing for a standard downhill mountain bike might have 60 TPI casing. On the other hand, a road or cross country performance bike like Schwinn Volare or Schwinn Fastback 2 might feature a 120 TPI casing.

Smaller thread size has higher TPI due to the lesser rubber in between the threads that makes the tire more flexible and lighter. There is a single sheet of casing in these road bike tires right at the center.

Each layer of nylon is known as ply and a casing with higher TPI will have a greater number of plies to increase puncture or cut resistance. We’ll talk about it in detail in the following text.

Types of TPI and Who should Choose What

Vittoria, a tire manufacturing company has the highest thread per inch. It makes 320 TPI tires while the lowest one by the company is 26 TPI. On average, the company provides its users with 120 TPI in the tires.
Michelin offers 33 TPI for its entry-level tires designed for free-riding or downhill racing. The intermediate tires come with 60 TPI while the high-end tires feature 127 TPI. Maxxis tires come with 60 TPI excluding the racing tires that come with 120 TPI.

A novice racer should go for a tire that provides the best value in terms of smoothness, lightness, and TPI count. And the price difference between the highest thread per inch and the lowest TPI is around $50.

According to the author of Bicycling magazine, Natascha Grief, a high TPI tire will be more noticeable when the rider is cornering. Such a tire will conform well to the surface.

Thinner TPI mountain bike tires are extremely resistant to cuts and punctures. Hence, if you are looking for a high mileage tire, choose one with the lower TPI. If a high-performance tire is your requirement, an advanced thread count will be the best pick.

There are different names of these casing as they have different features. It’s the matter of durability vs weight where ride quality and surface gripping are the secondary factors. In general terms, a heavier tire is always more durable than a lighter one.

TPI and Ride Quality

A single layer or ply offers the least amount of rolling resistance but it is the least durable as well. With more layers or plies, your tire becomes more cut and puncture-proof. But at the same time, you are compromising with rolling efficiency.

Additionally, with more plies, the carcass becomes stiffer and complicated. Some tires feature additional laminated layers to further improve durability. These layers are not part of the casing materials.

With these plies and laminate layers, your tire becomes more resilient. With a high quality 120 TPI casing and thick rubbered lamination, the advantages offered by the fabric will minimize. You can produce a better ride quality with a 60 TPI tire as compared to the double thread count. For more protection, you will need additional layers of rubber that will negate the advantages of high thread count.

This is the trait that differentiates one tire manufacturer from the other. Some of them use single-ply with additional protective layers. While others use dual plies with protective layers. Some of them do both and have different tire types on offer. They also provide you a variety of tires according to your preferences.

Layers and Reinforcements

With lower TPI fabric, the tire will be more durable and heavier. Higher TPI tires are flexible and light but they are not very durable either. Their smaller threads are very supple which allows the tires to comfortably conform with the surface. But the tire overall is more prone to damage.

The matter of choosing a casing for rear and front tire doesn’t have anything to do with traction and cornering. Rear tires are more exposed to beating as compared to front tires. Due to this reason, some people prefer to go with a heavier tire on the rear end.

Most of the lineups of tires begin with a single ply and the casing along with the sidewall does not come with a reinforcement. Therefore, they are lighter and prone to damage. Each tire manufacturer has different additions to make their tires more durable and puncture-resistant. They also create designs that are more accommodating towards tubeless applications.

Here are some of the casing options offered by the major tire manufacturers of the industry according to their threads per inch chart.

10 Casing Options by Major Tire Manufactures

Here are some of the casing options offered by the major tire manufacturers of the industry according to their threads per inch chart.

1. Kenda

• A dual-ply casing with an extra butyl rubber inserts right at the bead for reducing pinches.
• Dual-ply casing, bead-to-bead to reduce punctures.
• Dual-ply casing on the sidewalls for limiting cuts or punctures.
• A 120 TPI casing with added three panels to resist punctures along with a butyl insert close to the bead for resisting flats.

2. Schwalbe

• A heavy dual-ply tire with sidewalls reinforced for puncture protection.
• Heavy dual-ply casing without any additional puncture resistance.
• Four lightweight plies close to the bead and two lightweight plies right under the tread.
• Snakeskin casing with additional dual layers of sidewall reinforcement.
• Snakeskin layer featuring extra Raceguard safety.
• Just a layer of extra rubber for preventing punctures (Raceguard).
• Snakeskin setup that helps for tubeless installation.

3. Bontrager

• Dual-Ply for downhill racing.
• A 3-piece reinforcement on sidewalls and under the tread with in between gaps.
• A cut resisting layer for the sidewalls.

4. Specialized

• Dual-ply 60 TPI casing featuring butyl inserts right at the bead for protection against tears and pinches.
• A layer of puncture protection from bead-to-bead.
• A reinforced layer on the sidewalls for cuts resistivity.
• A butyl rubber wrapped bead to make your tire tubeless easily. 

5. Continental

• Additional rubber in the sidewall for tear resistivity.
• A cut-resistant layering that wraps around the tire.
• A light casing with some extra puncture resistivity.

6. WTB

• A full dual-ply casing that features a folding bead.
• Basic single ply that is tubeless compatible.

7. Hutchinson

• 2 layers of edge-to-edge puncture-proof fabric.
• 1 edge-to-edge puncture-proof layer.
• 1 lightweight puncture-proof layer.

8. Maxxis

• Dual-ply layer for sidewall safety (66 TPI each).
• 1 double-ply tire with 2 120 TPI layers.
• Additional butyl rubber layer right next to the bead within the sidewall.
• A cut-resistive layer on sidewalls
• Thin puncture-proof layer under the tire tread.

9. Michelin

• Edge-to-edge layer for venture-proof performance.
• Triple-ply (66 TPI each) for protection.
• Triple-ply (110 TPI each) casing that is heavy for cut resistivity.
• Lightweight triple-ply (150 TPI each) casing which is usually there on Michelin XC tires.

10. Vittoria

• Dual-ply casing that goes near the beads.
• Additional insert at the bottom for cut-resistivity.
• A tubeless-ready 120 TPI casing.
• A lighter weight tubeless-ready casing.
• Single-ply casing for folding bead.

Tubeless Designations

Several tire manufacturers are making their tires with tubeless compatibility. There are four different categories associated with tubed and tubeless tires.

1. Tires are designated as non-tubeless compatible.
2. Tubeless compatible tires with sealant.
3. Tubeless compatible tires with sealant and are UST (Universal Standard Tubeless) specified.
4. Tires that come with UST tubeless compatibility.

Non-tubeless compatible tires are only usable with tubes. If you use a sealant with these tires, it will damage the inside. Mostly, the tire bead is not tight enough to keep the tire secure to the rim if you don’t use a tube.

Tubeless compatible tires with sealant require rim tape for sealing the tire with the rim. A UST tire with sealant is just like the tubeless compatible tires with sealant. The only difference is that these tires are UST specified. They have a specific tire bead that meshes well with the UST compatible rims. Therefore, you will get tighter and a better seal that will prevent burping. But, you will need a sealant as well because the tire is not fully UST specified.

UST specified tires come with full compatibility. They don’t need any sealant to be fully airtight. You will need a UST rim and a UST tire to work with this category. And as there is no need for any sealant, UST tires are becoming more popular.

Final Word

Threads per inch or TPI has a significant role to play when it comes to weight and durability of a mountain bike tire. Different manufacturers are offering different types of TPIs. With time, the riding styles of the riders have changed and it has pushed the tire manufacturers to new limits.

Advanced suspension and wheel designs have changed. New riding styles are creating a demand for new types of tires. Sidewalls and tread surface are now equally prone to damage. Some tires can support an aggressive style of riding while maintaining a lower pressure.

Some people recommend the use of a durable tire, others choose to go for a 60 TPI tire for better traction. Depending upon the riding style, your front wheel might also take a lot of tolls. You have to honestly examine your riding style and demands. Choose the best tire with the appropriate threads per inch that can offer you durability and traction.

Rubber compounds, weights, and tread patterns have their importance as well. But you cannot ignore how casing along with any additional layers can influence your ride comfort. We are not dismissing the hidden elements of a tire. We are just saying that the hidden aspects associated with a tire are equally critical.

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