close
close

Innovative dual-chainset bike improves reliability on tough, critical rides

Theo

Chicago-based nonprofit World Bicycle Relief (WBR) doesn’t distribute just any bike: It distributes bikes designed to navigate the unpaved roads and rugged terrain of developing countries, giving people access to health care, education and economic opportunities that would otherwise be out of reach.

The original Buffalo Bicycle is the most rugged available for rural terrain, and he didn’t take the task of rethinking it lightly. With the Buffalo S2 Utility, he’s reworked the simple concept of a chain, gears, and pedals into a rarely seen unicorn: a two-chain drivetrain.

The first thing that comes to mind when looking at a dual chainring setup is… Why?! It seems like this layout adds extra weight and complications, plus an unnecessary and fragile chain, just to go against the conventional shifter and rear sprocket layout.

But that’s an industrialized-world first impression of a developing-world solution, and while that’s probably a legitimate question for an urban commuter bike aimed at North Americans or Europeans, it misses the mark on a bike built specifically to be an extra-durable daily workhorse… like a Land Cruiser 70 Series for those who can’t afford a Land Cruiser 70 Series, or have no way of accessing one.

World Bicycle Relief provides bicycles in places where mobility is difficult and solutions are hard to find
World Bicycle Relief provides bicycles in places where mobility is difficult and solutions are hard to find

Global Cyclist Aid

World Bicycle Relief says its Buffalo bikes are designed to be “extremely durable to meet the needs of people who travel long distances over rough terrain with a heavy load in some of the world’s harshest environments.” With this in mind, simplicity and robustness are absolutely key, and the redundant chain system is designed to provide a high-speed/low-speed solution that involves as few breakable and externally mounted parts as possible. These bikes are delivered to places that don’t have access to bike shops or overnight spare parts, so making something as strong and easy to repair as possible is a vital part of WBR’s work.

The original Buffalo bike was a single-speed for these reasons, but WBR identified the need for a low gear designed to make climbing and hauling cargo easier. Instead of outfitting the bike with a bunch of extra cogs, cables, and components, it split the drivetrain into two separate drives: a high chainring connected to a rear cog via a dedicated chain, and a low chainring chained to a second rear cog on the same hub. All the hardware is located on the right side of the bike, and the rider simply turns the bike back halfway to engage the freewheel, which can switch from high to low and vice versa.

The Buffalo S2 Utility's two-speed drivetrain features a switchable freewheel with two sprockets that are each paired to a corresponding chainring via their own single-speed chain.
The Buffalo S2 Utility’s two-speed drivetrain features a switchable freewheel with two sprockets that are each paired to a corresponding chainring via their own single-speed chain.

Global Cyclist Aid

A bike designed with two chains isn’t unprecedented, but it’s certainly not the norm at every bike shop we visited. We’ve seen a pair of asymmetrical chains used to make the ride less unstable, and we’ve seen an e-bike with a dedicated high-power motor and pedal chains, but nothing quite like the Buffalo S2. WBR calls its design an industry first, and it received its first U.S. patent for what it calls the AK2 freewheel.

Although chains are prone to breakage like any other component, they can usually be easily repaired in the field with a chain tool and spare links. And because the Buffalo S2 Utility has two separate chains, it can still be used even if one chain is damaged beyond field repair.

With its two-speed dual chain drivetrain, the Buffalo Bicycle Utility S2 can climb hills and carry loads more easily.
With its two-speed dual chain drivetrain, the Buffalo Bicycle Utility S2 can climb hills and carry loads more easily.

Global Cyclist Aid

The rest of the S2 Utility is designed to be equally simple and robust, centred around a TIG-welded carbon steel frame. Tough ‘deep section’ aluminium rims and puncture-resistant Kenda Buffalo tyres keep it moving. WBR says the dual-pivot caliper brakes are designed for easy use and adjustment, with the tubular rear rack rated to carry up to 100kg of cargo.

Before unveiling it at Eurobike 2024 this month, WBR developed the Buffalo S2 with the help of global bike and component manufacturers and spent two years testing it in sub-Saharan Africa and South America, ensuring it met the needs of its end users. It won a Eurobike Award for its design. Since its inception in 2005, the organization has delivered more than 800,000 bikes to communities around the world, well on its way to reaching its next goal of one million.

Source: World Bicycle Relief

Related Posts