Cranktank4 Holds Four Liters in the Frame Triangle

Water is no doubt the heaviest thing thing you’ll carry on your bike. And when considering where the heaviest items in your bikepacking gear kit should go, there’s no arguing that the lower frame triangle is the ideal location to maintain an optimal center of gravity. One popular method is to use a half-frame bag with two bottles placed in the lower triangle. This works well for centering the load, but you lose valuable packing volume with the unused space in the triangle. I typically use a full-size frame bag and always place heavy tools, spares, a spare water bladder, and food in that location, with a bottle under the down tube. But I’ve always wondered when someone would design a water tank for that placement, something that could come in especially handy on water-starved desert routes like the Camino Diablo or in the Moroccan Sahara. Enter the CrankTank4, a new product developed by Australia-based Adventure Hydration. The CrankTank4 secures to the base of a bike’s frame triangle and carries four liters of water.

The Cranktank4 is a triangular-shaped, food grade polyethylene container designed to sit low in the space between the down tube and seat tube of conventional bike frames. The “V” profile in the CrankTank4’s spine indents in the front and rear and allows it to adapt to fit a broad range of tube profiles and frame angle variations. It secures with two hook and loop “D” buckle straps.

The $75 CrankTank4 kit includes an insulated drinking tube with a bite valve and a quick disconnect fitting to allow rapid release from the tank cap so the tube can stay on the bike while you refill. The tube that comes with the kit is 120cm (47″) in length and can be shortened if need be. The CrankTank4 kit also includes a tube keeper that can be connected to the handlebars or other locations on the bike using included zip ties.

CrankTank4 Benefits

• Enough water for a full day. Four liters is about what most riders would need on an average day of riding, depending on the rider and the climate.
• Optimal weight distribution. The low center weight makes it the perfect position where it has minimal impact on handling when full.
• Space savings. Four liters of water fit in the same space as two standard bottles.
• Quick and easy to remove. CrankTank claims the CrankTank4 mounts securely but still is easy to remove.
• Designed to fit most conventional frame triangles. Cranktank4 was designed to as many standard triangle frames as possible—touring bikes, gravel bikes, road bikes, and mountain bikes. Find photos on their Instagram page to give you an idea. Rounded profile down tubes up to around 50mm are fine, and even some squared-off profiles work well.
• Weight Savings. The CrankTank4 weighs the same as three standard 750 ml bottles and cages, but holds the same amount as five standard bottles.

There were a few disadvantages that came to mind when I first saw the CrankTank4. One is that it might be difficult to clean. You can’t exactly fit your hand or a typical dish cleaning scrub brush inside it. Also, based on the photos, the polyethylene appears to be opaque, so it seems like it might be difficult to estimate how much water is left inside the tank. Lastly, it might be challenging to fit an additional bag with the CrankTank4 when using a small mountain bike frame.

Otherwise, the CrankTank4 appears to be an interesting solution, as mentioned, for desert routes or trips where you need to stow extra water. We hope to check one out for a review. In the meantime, find more info over at AdventureHydration.com.

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