Rapid Raptor


customized Harley-Davidson Softail Breakout


It's still a little while until spring. The Monza GP will bring it to life in all its colors

It is like the overture to a great symphony. A spring symphony. Ignition on, and not only the conductor’s display lights up in the most glorious colors. Rebuffini’s fittings are also brightly colored from the flanks, as if they wanted to strike their own chords. Euphony is also possible in color.

We’ll soon be driving again on a summer night, when we don’t want to have to feel for the switch for the main beam. Can’t you always have these illuminated fittings? You can’t. We’re not just standing in front of a Harley, we’re standing in front of a Thunderbike, a model from the precious GP series, and this time it’s called “GP Monza”.

The exclusive GP series

We have been building “Grand Prix” bikes for some time, once within the model ranges of our exclusive small series. Since 2018, we have been offering the GP based on the original Milwaukee Eight chassis. And we already presented our latest projectile based on the Breakout at the Custombike Show in December. Now you can see it here in full detail. So stay seated and hold on tight!

You’ll notice it at first glance: This time, Kruse-Design has given it a glossy finish. This is rare for our GPs. But this is just the beginning.


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Naturally, the Monza rolls on our large GP wheels, 23 inches at the front and 21 inches at the rear. They are monoblock wheels, milled from the solid, designed in bicolor. The GPs also have to meet our high driving physics requirements. With a width of 260 millimeters, the rear tire is almost modest in size, but this ensures directional stability because the widths at the front and rear are not too far apart. Wider would certainly have been better for show, but the Monza delivers enough show as it is.

The elegant combination of matt black and bicolor design gives the GP wheel an impressive aesthetic and sets stylish accents.

The Monza is an absolute highlight for fans of modern and sporty custom bikes.

“Completely new front end: milled triple clamps, own stanchions, GP handlebar halves, dip tubes with mounts for the impressive 340-millimeter discs – all made in-house.”

The 21-inch rear wheel is mounted in a single-sided swingarm. This is actually a technical solution from racing to facilitate quick tire changes. But it also looks impressive, especially with the large-format perimeter brake on the left-hand side. We have also found a solution to match the extravagant tire format to a functioning ABS, as we were able to relocate the encoder sensors from the wheel bearing to the hub.

And, of course, we also gave our Monza an adjustable chassis. It can be raised and lowered on command. No, not with Airride this time, because that could stamp under the acceleration pressure. That’s why we installed a hydraulic solution. This was necessary because we also gave the 117 engine more pressure with a suitable tuning. Not so much in terms of power at the end of the flagpole, by the way, but in favor of more aggressive torque from below.

Even the tank has been given its own design, of course, including the one from our GP series. Because of the components for the injection system in the series tank, tank modifications of this size are no longer common today. But we can do that too.

The silencers come from us, naturally from the GP series

The front spoiler is not bolted but welded on

You can search for screws for a long time. The rear fender is welded to the frame

Complete front end from Thunderbike

The front end has been completely renovated, all by us: triple clamps milled from solid material, our own stanchions with attached GP handlebar halves, our own dip tubes with mounts for the brake callipers of the huge 340 millimeter discs. The fork can be retuned from traffic light to traffic light, because our GPs are always based on drag racing. Every start has to offer our customers the experience of a new sprint.

So much for the knock-out facts. We want to give you at least a brief look at the rear and front spoiler. You’ll be looking for screws there for nothing. Both are neatly welded in the service of a clean look. These two parts are not store items and are not listed in our parts list. Instead, we have linked the comparable bolt-on parts.

We told you: just waking up the ignition of our GP Monza makes a symphony resound. Our GP silencers will tell you what it sounds like in every movement. Their sound also has a color.

Parts & Details

  • Thunderbike EFI Cover black wrinkle
  • Thunderbike Exhaust System Grand Prix
  • Thunderbike Frontend Grand Prix
  • Thunderbike Clip-On Handlebars Grand Prix bicolor
  • Thunderbike Headlamp Cap black
  • Thunderbike Hydraulic clutch Conversion Kit black
  • Thunderbike Phantom E Grips
  • Thunderbike Toppers Base
  • Rebuffini RR90 Control & Switch Set hydraulic, black matt
  • Motogadget Mirror mo.view Race left
  • Thunderbike Forward Controls Grand Prix black
  • Thunderbike Turn Signals Stripe LED with housing
  • Thunderbike Custom Alu Fuel Tank GP-Style
  • Thunderbike Ignition Coil Relocation Kit black
  • Thunderbike Front Fender GP Style
  • Thunderbike License Plate Frame Inside Plate
  • Thunderbike License Plate Lighting
  • Thunderbike Airbox Cover Oval Grand Prix
  • Thunderbike Derby Cover Drilled contrast cut
  • Thunderbike Timer Cover Drilled
  • Thunderbike Brake Disc Streetmaster
  • Thunderbike Brembo Radial Monoblock M4 Caliper Set black
  • Thunderbike Single-Side Swingarm Kit 21'' Alu
  • Thunderbike Pulley Grand Prix
  • Thunderbike Grand Prix rear wheel 9.0x21
  • Thunderbike Grand Prix front wheel 4.0x23
  • Metzeler Cruisetec Rear Tire 260/35VR21 83V
  • Avon Tyres Avon Cobra Chrome , Front/Rear, 130/60VR23 (65V)
  • Thunderbike Rear Fender GP-Style 260 mm
  • Thunderbike Chin Fairing GP Short



Author / Editor

Michael Ahlsdorf

Your Contact


Nico Schnepel

Customparts, Dealer Support

0049 2852 - 6777-30
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Roman Reiners

Customparts, Dealer Support

0049 2852 - 6777-30
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Julian Segler

Sales, Financing, Rental, Custombikes

0049 2852 - 6777-41
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Thomas Emky

Custombikes Service Workshop

0049 2852 - 6777-56
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More Breakout Customs

You can find Thunderbike Parts and original Harley-Davidson Parts  in our online shop.


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