Rob’s bike is done, rushed through the final stages to get off to the World Hardcourt Bike Polo Championship in Switzerland.
Altogether I’m pretty pleased with how this one turned out. The computer modelling to get the seat-tube curve concentric with the wheel worked out superbly. For the gear that Rob was running, the chainstay length could be calculated and the centre of the curve placed at the centre of the axle. It wasn’t until the whole bike was built up and the chain tensioned that we were able to check how it looked.
The reason for the curved seat tube is to eliminate toe overlap. This bike shares very similar geometry to Vive’s bike, and all Whiskeys to date, with super quick and nimble handling balanced with a measure of stability. In this latest evolution, the curved seat tube simply moves the cranks back away from the front wheel. This is a no compromise bike. There is no space wasted and no curve that doesn’t need to be there. The downtube is straight gauge tubing to improve crash toughness. You could basically ride this thing straight into a wall and it will just bounce off. No amount of gussetting or reinforcing of the headtube joint will give that same toughness. After seeing forum photos of polo bikes that had folded at the end of the butted section it became clear that the small weight penalty was worthwhile.
With such short chainstays, and fat tyres (will fit 26 x 2″), fitting chainstays / tyre / chainrings / cranks became an issue. That’s why the whole thing needed to be modelled in the computer first.
Here’s a photoshop mock up during work on the frame:
To recap:
Sand filled tube bent

BB scalloped and brazed

Built (click for ani-gif)

Painted

Collected

Thanks for the lovely bottle of Whiskey Rob and good luck in Switzerland and London!















