Thunderbike Radical Viper • Harley-Davidson FXBB Street Bob Umbau

What's radical about the Radical Viper?

Before we start playing with words, let's quickly clarify what is radical about the Radical Viper, which is everything!

Admittedly, at first glance, the green shade that our Radical Viper is sporting appears less radical. However, it is rather exclusive and reminiscent of a colour you would otherwise only see on an AMG Mercedes. This actually proves the point: Exclusivity can be radical, too.

Radical components

What was once a 2023 114 Street Bob is now the carrier of a number of components from our parts series of the same name. The highlight is the Fork Radical 2.0, an improved version of our well-known Radical Springer fork. With its clean outlines, it stands out from the classic, dust-collecting appearance of a conventional Springer fork. The Radical 2.0 is simply more radical and comes with a range of other components.

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The brake caliper and anchor are also called Radical; the anchor is even called Radical 2.0. As such, they are matched not only to the fork, but also to our 340-millimetre spoke brake disc. The exalted Blade Runner handlebar is also part of the Radical programme, in which the handlebars are custom flange-mounted on the upper triple tree clamp instead of being placed on risers.

To avoid spoiling the look of the front end with cables and Bowden cables, the Radical Viper has a hydraulic clutch and our Turnsignals Stripe are hidden under its fittings. The satin-finish grips provide an enjoyable tactile experience. The forward controls and shift pegs that come pre-installed with our kit are also satin-finished. Boots won’t slip on them either.

The Radical 2.0 concept is matched with brake anchors and a radially bolted brake calliper.

The Blade Runner handlebars are not mounted on risers; instead, they are flanged to the Radical fork.

We switched to a hydraulic clutch and concealed the indicator stripes effectively.

Air Ride at the front and rear

Have we mentioned the Air Ride on the Radical 2.0 yet? It’s part of the package. At the rear, however, we have also fitted the Radical Viper with our own air suspension as part of our swingarm conversion to a pulley brake. This removes the disc from the right-hand side of the field of vision. The disk and pulley here also come from our Spoke series. They fit perfectly with our New Digger bicolour wheels thanks to their design. Both have, of course, been given a new look — we are Thunderbike, after all. The Radical Viper rolls on 21-inch wheels at the front and 18-inch wheels at the rear instead of the standard 19-inch and 16-inch respectively.

The New Digger wheels are bicolor. They have a new format. The front is 21 inches. The rear is 18 inches.

At the rear, we took the opportunity to increase the tyre width from 150 to 200 millimetres. The adapted steel fender with integrated micro taillights sits next to the tyre. In front of this is a leather-covered seat on the matching steel seat shell.

Our side licence plate holder with an Inside licence plate ensures that nothing disturbs the rear composition. Our aluminium custom tank creates a consistent look between the front and rear.

Thanks to Air Ride, the steel rear fender hugs the tyre and the rear lights are well hidden.

Another important feature for facial recognition is our unbreakable headlight. Torque covers for the ignition and clutch, as well as the oval torque airbox cover, complete the flowing lines of the Radical Viper. The Kess-Tech silencers serve as a reminder that this Harley can be made to roar at the push of a button — and completely legally.

The brake disc has disappeared between the wheel and the pulley on the left.

This is what a clean rear end looks like.

Our in-house custom aluminium tank has a capacity of 15 litres.

Radical and exclusive

That is radical. And it’s exclusive. If I may say so, it is also aesthetically pleasing, with clean, flowing lines. One glance is not enough to take it all in. We all agree that a second glance will not be enough either. This is how Thunderbike customisation works.