customized Harley-Davidson Sportster S 1250

Finally online! The Thundertalk between Lance David Arnold and Andreas Bergerforth.

Lance is a well-known German racing driver. He has proven his skills as a driver for Porsche. In addition to his successful racing career, he also works as a presenter for Automobil Vox. Thanks to their racing experience, the Thundertalk is particularly informative about the sporty Harley.


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This hot appliance is the latest addition to the SPS series

The Sportster S with its modern chassis and extremely agile Rev-Max 1250T engine, which not only delivers a wide rev range thanks to variable timing, but also a whopping 122 hp peak power on the road, provides the perfect basis for supersport custom projects made by Thunderbike.

In this case, our project not only received the sporty GT wheels in 6.00 x 18 inch at the rear and 3.50 x 21 inch at the front, but for the first time we also designed the front wheel of a Sportster S to accommodate two brake discs. In order to be able to fit two brake callipers, the upside-down fork was given new milled brake calliper mounts and an additional radial brake calliper by brembo. To improve the response behaviour, the stanchions were also coated in gold DLC at the same time.


Seating position

To support this sporty concept, the bike was fitted with our relocated footrest system and triple clamps with flat handlebar mounts specially developed for the Sportster S. This means that the riding position now matches the new riding dynamics of our Sportster S 100 per cent.

Driving dynamics

This new front end with 21″ front wheel and 340 mm brake discs not only looks sporty. The conversion also makes the bike more dynamic, as the narrower front tyre significantly improves handling. The conversion of the brake system also makes a sporty contribution, with the 2-disc brakes doing their job with incredible ease and leaving nothing to be desired.

This project is further enhanced by many finely milled parts from our range: radiator cowling, engine cover, pulley cover, shock absorber cover, headlight cowling, grips, indicators etc. are all from our SPS series.


The paint concept comes from Kruse Design and consistently emphasises the sporting ambitions.

The slim exhaust system comes from J&H and fits in perfectly with the overall concept.

The seat was made by Spirit Leather and not only looks good, it also has an optimised shape that provides better support.

Parts & Details

  • Thunderbike Front Fender SP-S
  • Thunderbike Windshield Kit black
  • Thunderbike Triple Tree SP-S contrast cut
  • Thunderbike Turn Signal Set Quick-Stripe 54mm Dark black
  • Thunderbike Taillight & Turn Signal Kit black
  • Thunderbike Mirror Bracket Set black
  • Thunderbike Side Mount Licence Plate Bracket Medium Pro black matt
  • Thunderbike License Plate Frame Inside Plate
  • Thunderbike License Plate Lighting
  • Thunderbike Shock Adjusting Knob satin black
  • Thunderbike Foot Controls SP-S recessed contrast cut
  • Thunderbike Rider Footpeg Set SP-S black
  • Thunderbike Shift-Peg satin cut
  • Thunderbike Grips SP-S satin black cut
  • Thunderbike Pulley Cover front contrast cut
  • Thunderbike Frame Cover black
  • Thunderbike Radiator shroud set bicolor
  • Thunderbike Clutch Cover SP-S
  • Thunderbike Timer Cover
  • Thunderbike Heat exchanger Cover black
  • Thunderbike Alternator Cover SP-S
  • Thunderbike Belt Guard black
  • Thunderbike Swing Axle Cover black
  • Thunderbike Handlebar SP-S1 Alu 80.5cm black matt
  • Thunderbike GT Wheel
  • Thunderbike Brake Disc Vegas Floated 340mm
  • Rizoma Mirror Dynamic black
  • Thunderbike Fork modification Radial Calipers Pro Performance black
  • Thunderbike Modification Kit to Dual Brake Caliper Brembo Radial
  • Thunderbike Pulley Cover front SP-S contrast cut
  • Thunderbike Raising Deflection lever +35mm
  • Thunderbike Modification extended Kickstand + 20mm


On the Road


Author / Editor

Kim Lara Bergerforth

Your Contact


Thomas Emky

Custombikes Service Workshop

0049 2852 - 6777-56
Send an email


Julian Segler

Sales, Financing, Rental, Custombikes

0049 2852 - 6777-41
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Roman Reiners

Customparts, Dealer Support

0049 2852 - 6777-30
Send an email


Nico Schnepel

Customparts, Dealer Support

0049 2852 - 6777-30
Send an email

More Sportster S Customs

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


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