Sinter Model 037 Tektro

Tektro's four-piston cargo-bike caliper is the heavy-duty version of the same cargo-bike brake platform that the Model 036 two-piston covers. Four pistons, more pad area, designed for the heaviest cargo bikes; long-tail family cargo, two-wheeled delivery bikes hauling commercial loads, and the new generation of long-john cargo bikes carrying multiple passengers. The Sinter Model 037 is the organic-compound pad for that four-piston cargo caliper.

What's in the kit

One caliper's worth of pads (2 pads, left and right) for the Tektro four-piston cargo pocket. The kit ships with bedding-in instructions. Order two kits if you're replacing front and rear pads on the same service.

Fits

Tektro 4-piston cargo-bike caliper:

• Tektro four-piston cargo-spec hydraulic calipers; the high-load platform behind heavy cargo bike OE channels

The four-piston caliper increases the pad surface area against the rotor and reduces the per-piston load, which keeps pad temperatures lower under the sustained heavy-cargo braking pattern. Cargo-bike OE builders specify this caliper for the heaviest gross-weight applications.

Compound and feel

Sinter's organic ceramic-loaded compound on a four-piston cargo caliper is the right compound choice for the same reason it's the right choice on the two-piston cargo caliper: cargo-bike riding is dominated by sustained moderate-pressure braking, not single hard stops, and organic-matrix modulation outperforms sintered pad raw heat capacity in that pattern. The Model 037's organic compound stays inside its working envelope on a fully-loaded long-tail cargo descent, where the larger pad surface area and four-piston caliper layout do the bulk of the thermal management work.

Specs

• Compound: organic (ceramic-loaded, resin-bound)
• Backing plate: steel
• Pad shape: Tektro 4-piston cargo
• Pads per package: 2 (one caliper)
• Built specifically for cargo-bike applications

Includes: 2 pads (left and right), bedding-in instructions.

Sinter Ljubljana, since 1969

The same Slovenian plant that supplies Sinter pads to motorcycle OEMs at scale designs the bicycle compound for the use cases the bicycle world is actually asking for; including the long-tail cargo bike segment that conventional bicycle-pad makers have under-served. Sinter has been making friction materials in Ljubljana since 1969, and developed the first disc brake pads in the former Yugoslavia in 1972. Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. Euro Toolworks distributes both brands in North America. The Model 037 is the four-piston cargo pad in this catalog, sized for the long-tail family cargo and commercial-delivery builds the bicycle market is growing into.

Pro tip from our mechanics

Four-piston cargo calipers reward a careful piston-spread step more than two-piston calipers do, because the four pistons can retract unevenly over a season of cargo use. Before installing the fresh Sinter pads, work each piston individually back to a uniform retracted position with a piston-spreader; uneven retraction on a fully-loaded cargo bike produces the characteristic “rear brake drags on flats” complaint within a few weeks of pad-life.

Compound choice, fitment, and where the Elite line fits in the catalog are covered in How to choose Sinter brake pads →.

FAQ

Which brakes does the Sinter Model 037 fit? This pad is made for Tektro four-piston hydraulic calipers, the heavier-duty units used on cargo and e-bikes, so it suits the four-piston version rather than a two-piston caliper. Because Tektro uses more than one pad shape, the reliable check is to remove a worn pad and match the backing plate, mounting tab, and retaining-pin hole to this one, or read the model number stamped on the old pad. The physical shape is what matters. If you are unsure, send us a photo of the worn pad and we'll verify the fit.

Are these sintered or organic pads? They are organic. Despite the name, Sinter only make organic pads, not sintered-metal. The Black s550 compound is an organic ceramic-loaded material. Compared with sintered pads, organic compounds run cooler at the caliper, give more lever feedback and modulation, stay quieter, and cause less rotor wear and vibration.

How do I bed in the new pads? Bedding transfers an even layer of pad material onto the rotor so the pads reach full power. After fitting, ride up to a moderate speed on flat ground and brake firmly to nearly walking pace without locking the wheel, then release. Repeat that ten to twenty times, letting the brake cool between efforts and avoiding a full stop with the lever held. Expect bite to build over the first few rides; with a loaded cargo bike, give it extra passes.

Why do I have to push the pistons back before fitting new pads? As the old pads wore, the caliper pistons advanced to keep contact with the rotor. New pads are thicker, so the pistons sit too far out and the new pads will not clear the rotor. Before installing, push or spread the pistons back to a uniform retracted position with a piston spreader or a plastic tire lever. On this four-piston caliper, work each piston back individually, since they can retract unevenly over a season of cargo use.