Harley-Davidson GP-Monza Is Probably the Most Expensive Custom Breakout in the World

The model has been around in Harley's lineup, with interruptions in some markets, ever since a decade ago. It is presently sold in the U.S. as a raked-out cruiser with a V-Twin muscle at its core, and as such it sells pretty well.

For some reason Americans were never the ones to take the lead in transforming stock Harleys into something much more extreme. And yet the world is filled with such rides, an overwhelming majority of them Breakouts, coming from foreign garages that make more than a decent living from this.

Over in Germany, for instance, there is a shop called Thunderbike whose people breathe Breakouts. We've seen many incredible projects based on this model coming out of their doors over the years, and the pace seems to have accelerated since the unveiling of the new version, the one powered by the 117 engine, not long ago.

The most recent Breakout-based transformation the Germans can brag about is the GP-Monza we have here, a radical interpretation of the iconic ride. And more than that, perhaps the most expensive Breakout interpretation of modern times.

The bike is so different from its former self that you could hardly recognize it. Long, low, and mean, it wears a completely overhauled body, including the fuel tank, something we're not used to seeing modified by Thunderbike, a paint job for the ages, and a very will-do attitude.

Starting from the ground up, we get wheels from the Thunderbike GP series, which are sized 23 inches at the front and 21 inches (260 mm wide) at the rear. They are not just any custom wheels but milled from solid aluminum, and that makes them incredibly expensive – just the rear wheel, for instance, is worth as much as many new motorcycles out there: 16,154 euros ($17,512 at today's exchange rates).

The wheel at the back is supported by an aftermarket single-sided swingarm, while a custom fork backs the one at the front. The entire ride rests on an adjustable suspension system that is hydraulic in nature instead of the usual air ride.

Thunderbike admits to having installed no less than 30 custom parts on the Breakout to make it what it is now. Of them, the most expensive are the exhaust system (made in-house by the Germans), the above-mentioned wheels, and the fully custom front end (comprising kit the forks, triple clamps, handlebars, and even brake caliper).

All of these parts combined, but not including the base motorcycle, the paint job, and man hours spent on transforming the Harley, amount to 53,375 euros ($57,870). For reference, that's almost three times the starting price of a brand-new but stock Breakout, and probably one of the most expensive custom bikes in the world.