Kenda Tire factory tour shows how to make bicycle tires

Kenda is one of the largest bicycle tire manufacturers in the world, and they make car, ATV, scooter and various other tires, too. We took a tour of their bicycle tire factory in the Yuanlin Township, Changhua County, in Taiwan. Turns out they also make inner tubes here, which is in Part 2, and cooler than you think.

They’ve been at it since 1962 in this original location. Now, they have more than 1000 employees and 11 locations, two of them in Taiwan. The complex is sprawling, hidden by the normal office building facade. Inside the delivery portal lies a vast tunnel running past building after building. The bike tires use much of it, with rubber moving from section to section, floor to floor, as it goes from raw material to a finished, rideable product. Here’s how it happens…

Kenda Tire factory tour shows how to make bicycle tires

Kenda Tire factory tour shows how to make bicycle tires

Get through the gate and walk to the center and you’ll be staring down what seems like a mile of factory. They make more than just bike tires at this location, but each type of tire seems to mostly stick to its own sections.

kenda tire factory tour - raw rubber arrives and is mixed with silica and carbon to create the proper color and durometer

Rubber arrives in its natural state…

kenda tire factory tour - raw rubber arrives and is mixed with silica and carbon to create the proper color and durometer

…then is mixed with silica to create the proper durometer and carbon to turn it black. Other materials can be blended in to create different color tires.

kenda tire factory tour - raw rubber arrives and is mixed with silica and carbon to create the proper color and durometer

They sometimes use multiple blending steps, adding more silica on a second mixing, to end up with the right durometer.

kenda tire factory tour - raw rubber arrives and is mixed with silica and carbon to create the proper color and durometer

Everything is heated, melted and turned in monstrous machines with huge drums that twist and fold it into itself repeatedly.

UPDATE: Kenda has asked that we remove the videos for now, hoping we can get them back online in the future.

kenda tire factory tour - raw rubber arrives and is mixed with silica and carbon to create the proper color and durometer

kenda tire factory tour - raw rubber arrives and is mixed with silica and carbon to create the proper color and durometer

The end result are giant sheets of rubber, which are then sliced into appropriate widths and moved to the next stage.

kenda factory tour - spools of wire bead are turned into rubber coated wire beads for use in bicycle tires

kenda factory tour - spools of wire bead are turned into rubber coated wire beads for use in bicycle tires

Meanwhile, giant spools of wire are turned into wire beads for DH and less expensive bicycle tires. The wire is pulled and manipulated to get it to the correct diameter and roundness.

kenda factory tour - spools of wire bead are turned into rubber coated wire beads for use in bicycle tires

kenda factory tour - spools of wire bead are turned into rubber coated wire beads for use in bicycle tires

Then it runs thru a machine that melts rubber onto it. Note the bare wire coming in on the right, and exiting on left coated in rubber.

kenda factory tour - spools of wire bead are turned into rubber coated wire beads for use in bicycle tires

kenda factory tour - spools of wire bead are turned into rubber coated wire beads for use in bicycle tires

A wire is then bent into a circle, cut and taped to hold its shape. A worker pulls them from the machine, then they’re moved over to this testing station to check circumference. Once they pass inspection, they’re sent up to the tire layup station.

kenda factory tour - rubber is flattened and layered to create a thick tread section and casing

By this time, the rubber has moved on to the extrusion process to create the tread layer. It’s folded, layered as necessary to create a single or dual density rubber compound, then extruded into the basic profile needed for the intended tire. Above, you’re probably looking at the rubber for a tire like the Happy Medium, which has lower profile center knobs with taller side knobs – so, the rubber will be a little thicker at the outside edge of the tread.

After running through a cooling batch, the tread layer is rolled up with a coarse cloth between layers to prevent sticking.

Elsewhere in the building, they’re coating the base casing fabric with rubber. Depending on the ply (30tpi, 60tpi, 120tpi, etc.), different rubber compounds are used to ensure they saturate the fabric.

The roll is then cut into strips based on the tire size and model it’s going on. The angle of the cut is also customized to create the correct bias. The strips are then fed by a worker into a machine that connects them and rolls them up for transport to the next step.

Once the beads, casings and tread blocks are all created, they are fed into this machine for construction into a raw tire. Here’s how it works…

UPDATE: Video removed, per Kenda’s request.

kenda factory tour - how a bicycle tire is laid up to create the casing and tread layers before molding

The finished result is a layered, flat tire that’s ready to be molded.

These blanks are rolled to another building with rows of heat presses.

The layers are very visible prior to molding.

First it’s stretched and put onto a rubber tube…

…then placed in the oven and pressurized into a mold to create the tread pattern. The heat also cures it, altering the rubber’s characteristics to turn it into the final desired durometer and fuse all of the layers together.

Each and every tire is set up and placed into the molds by hand, removed by hand and checked over for any obvious flaws. Then they’re bundled up and sent to another section for quality control.

After curing, every tire is checked for size and weight balance. There are rooms and rooms of finished tires waiting to be QC’d, then stacks upon stacks of approved tires ready to go to packaging. All packaging and boxing happens onsite, too, then they’re shipped off around the world.

Kenda’s U.S. facility houses their North American sales and support, but also doubles as their advanced research lab. The new tires we’ve seen recently (and some cool ones coming this fall) were developed there. They will be made at this Taiwanese factory, adding to the roughly 15,000 bicycle tires they make per day!

Stay tuned for Part Two to see how their tubes are made.

KendaTire.com

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20 COMMENTS

    • Gustav, you didn’t miss the link, Tyler did. Hoping it gets fixed soon because that sounds interesting and part 2 seems even more so.

  1. I’m surprised that Kenda bothers to measure weights for QC. I bought some major name brand tires (Schwalbe) that were way way out of specified weight. It’s quite disappointing that Kenda can do this when Schwalbe doesn’t.

  2. Keep in mind that “QC” doesn’t mean “each one is perfect.” Moreover QC standards are dictated by the manufacturer so they could pick anything from “is the tire black” to “does this actually adhere to published weights” and call it QC.

  3. When I was a PD mgr many years ago, someone put a bunch of Kenda sample tires in my office and shut the door when I was in China for a week. The smell wouldn’t go away for over a month… terrible!

  4. Are you kidding me with the hand made tires. Our tires should cost $400 each given the time and skill it takes to make one tire. Without the size change calibration it took about 4 minutes to make one. That is crazy. But really cool.

  5. Great article! I used to work for Michelin and I’m amazed that Kenda was willing to share this much information and the videos!…I had a sign a 10 Year confidentiality Agreement when I left Michelin that I wouldn’t share any of their tire-making technology haha.

  6. Factory makes the tires for $5, sold to distributor for $15, sold to store for $40 and so on… Doubt those workers are well paid

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