The Empire AP-1: Ahead of its time, the AP-1 remains at the pinnacle of downhill bicycle technology. From the beautiful, one piece main frame to the hollow, section sand-cast aluminium swing arm, the adjustable dropouts to the incorporated cable routing, the custom graphics to the motocross-style brake carrier, the AP-1 is an engineering masterpiece, and all made in the UK. The AP-1 is also simple in construction, easily assembled and adjusted, provides a whisper-quiet ride with phenomenal grip and manoeuvrability. This downhill cycle also boasts exceptional acceleration combined with truly progressive suspension damping. This unique product is now available to buy direct from Empire Cycles Limited. There is also an increasing network of agents who are Empire enthusiasts who can offer a more local sales route for you.
FEATURES OF THE EMPIRE AP-1
Construction of the Empire Cycles AP-1
The Empire Cycles AP-1 frame is a world-first three-piece precision sand-cast structure. It is manufactured in the UK from L169 military grade casting alloy, heat-treated to a TF condition. The three components (main frame, swing arm, seat tower) then receive non-destructive testing (NDT) which is real-time x-ray. Each part is methodically x-rayed to check critical areas and ensure consistent performance. The surface finish consists of a two-stage process. First, a stainless steel bead blast homogenises the surface. This is expertly performed by hand as after exhaustive testing, we have found no other way. Second is the hard anodising giving the trade-mark military gray colour. This type of anodising is the toughest available, and is only available in gray. The result is a frame that remains highly resistant to damage. Essentially, it is armour-plated. Finally, the three components are machined using high-precision CNC vertical machining centres. Machining the components as the final operation ensures absolute precision in the finished product.
Empire AP-1 Bearings
The Empire Cycles AP-1 utilises full-compliment needle-roller bearings, manufactured by INA. These bearings are the best available for the pivot because they are designed to take high loads in a reciprocating motion. The AP-1 swing arm rotates through 25 degrees in its action. The force from this movement is spread across all of the needles within the bearings resulting in precise, reliable service throughout their considerable life.
High Single Pivot
A high single pivot was selected for several reasons. It will yield a rearward wheel action for the first half of the suspension channel resulting in excellent high speed compression damping. Secondly, the position of the pivot results in a linear rising rate of the geometry (so it does not clash with the shock absorber tuning). Thirdly, the widest possible positioning of the bearings is obtained for a super stiff pivot arrangement. Finally, the rearward axel path of the rear wheel matches the rearward axel path of the front wheel thus maintaining the wheelbase dimensions. This results in increased stability.
Chain Torque Idler
The chain torque idler corrects the chain line for the high single pivot. The short distance between the centre of the idler and the pivot eliminates wasted energy when sprinting. The secondary benefit of this idler is to allow the rider to set the AP-1 up using multiple chain ring sizes without affecting the chain line. This results in consistent suspension performance.
Wheelbase Adjustment
The rear wheel can easily be set up in three different positions. This allows the rider the option to adjust the wheelbase depending on track conditions. Increasing the length of the swing arm also results in increased rear wheel travel.
1:2.8 Ratio Rising Rate
The geometry of the swing arm was specifically designed around a 1:2.8 ratio so that the rear shock absorbers can be optimally tuned.
Sprung to Un-sprung Mass
The sprung mass comprises all of the components that are sitting on the suspension plus some of the suspension components themselves. The un-sprung mass comprises all of the components that are below the suspension plus some of the suspension components themselves. When looking at suspension performance it is highly beneficial to have a high sprung to un-sprung mass ratio. This will give superior grip and road-holding. To this end, lighter machines will be at a significant disadvantage as it is difficult to reduce the un-sprung mass by the same proportion as the sprung mass. The basic principles of the sprung to un-sprung mass ratio are very simple: for a high ratio, very light wheels, swing arm, break callipers and suspension components need to be coupled with a relatively heavy main frame. The Empire AP-1 has an approximate mass ratio of 70/30 which is very high for this type of bike, giving excellent grip and suspension characteristics. This has been documented time and time again in independent product reviews.
ISCG 05 Mounts / Custom Chain Guide
The Empire Cycles AP-1 is equipped with international standard chain guide 05 mounts onto which are fitted, as standard, Empire’s own lower chain guide. This eliminates the need for after-market chain guide purchase. The guide is fully integrated and works seamlessly with the upper idler forming a complete chain guide arrangement.
