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A Closer Look at the Forbidden DH Bike at Fort William World Champs

forbidden dh bike inverted four bar high pivot downhill carbon frame non drive side view
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The Forbidden team is racing an all-new dedicated DH bike in Fort William this weekend, where the 2023 UCI Downhill World Champions will be crowned. We got some detailed photographs of the new frame, and a little insight from Forbidden’s Pat Campbell-Jenner.

forbidden dh bike inverted four bar high pivot downhill mullet configuration

Forbidden Downhill Bike

The Forbidden downhill frame is a full carbon affair, with modular dropouts to allow for wheel size changes. This particular frame is piloted by a man whose job is normally team mechanic, but this week he is representing Canada as an Elite DH racer. Emmy Lan, a rider who is absolutely crushing EDR this season, is also racing the new DH bike at World Champs.

This weekend, Anthony Poulson (affectionately known as “Ant-Man”) is running a mullet configuration on this medium frame. Emmy Lan is running a mullet setup too, on the small frame. Aside from wheel size and chainstay length, no other adjustments are possible on the new DH frame.

forbidden dh bike shock tunnel

The Forbidden DH frame runs a familiar linkage layout, very similar to what we see implemented on the Forbidden Druid, with longer links delivering its 200mm of rear wheel travel. Of course, the kinematic is also tweaked to take on the high speeds and big compressions of World Cup DH racing.

forbidden dh bike inverted 4-bar linkage drive side view

It is an inverted four-bar linkage, wherein the lower link rotates clockwise as the rear wheel is displaced, driving the shock into compression. As it does so, the chainstay also arcs rearward, delivering a rearward rear axle path. As such, the effective rear-center length increases as the bike is pushed through its rear wheel travel, a feature we have come to expect from Forbidden.

forbidden dh bike inverted 4-bar linkage nds view

Such a layout would result in significant chain growth and the undesirable ride characteristics that come with it, like pedal kickback, if it weren’t for the idler pulley that routes the chain closer to that high main pivot location on the seat tube. The Forbidden DH bike runs an 18t idler pulley, the location of which cannot be adjusted.

forbidden dh bike 4-bar high pivot idler pulley 18t

Forbidden aren’t revealing too much about geometry or kinematic yet, but we are told it exhibits more anti-squat than the Druid, with more mid-stroke support.

The as-of-yet unnamed Forbidden DH bike shares much of its frame hardware with the Druid, including the rear axle. Indeed, this DH frame actually runs Boost rear end spacing (12mm x 148mm) as opposed to the 157mm spacing more commonly seen on DH bikes. That means the rear wheel of any modern trail or enduro bike is likely to fit this frame.

Cable routing is external, running underneath the 3D printed rubber headtube protection. The shock fender on this pre-production frame is also 3D printed.

Pat Campbell-Jenner from Forbidden tells us complete builds and frame only will be offered. No word on a release date just yet. Stay tuned!


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