Pushing the Testing Envelope

While the eyes of the BMX world were focussed on the last turn at Tulsa and that controversial move, Gate8 were quietly putting two new variants of their KW01 frame to work on the track.

On a freezing cold day in Birmingham England, reigning National Champion Miguel Gaboleiro set to work on testing. The new iterations of the KW01 race frame featured a revised tube set for the rear triangle, a longer rear end (based on team rider requests), a modified dropout system, new cable routing and a refined brake system.

Universal compatibility

The design brief of the Gate 8 KW01 has used the principle of ‘universal compatibility’ as its mantra. With so many differing 'standards' in BMX it’s tough to make a fame that will work with every component. A tough challenge but one we’ve accepted. By using a modular plate system the KW01 is able to accommodate 10mm, 15mm and 20mm rear hubs. Integrating the optional disc adapter to that system allows purists to run v-brakes whilst still supporting the more powerful hydraulic brake option which has gathered momentum in recent years.

The aim of today’s test was to see if refinements to the original design (still going strong after 2 months of testing) could achieve both reduced weight and improved function.

The new rear triangle was an instant hit with Miguel, as the enhanced tube set delivered a noticeable increase in stiffness out of the gate. The modified chain stay bend placement added more length from the bottom bracket to accommodate a longer chain stay bridge for additional stiffness and increased the crank clearance whilst maintaining the trademark tight curves around the rear tyre. The new under seat stay cable routing further improved the line of the hydraulic cable and ensured an unrestricted run to the XT calliper.

The KW01 rear dropout is going to offer the widest range of rider adjustment of any production frame with a whopping 20mm of adjustment at the rear end. Like more stability, push it back. Like an easier pick up, slam it forward. That level of adjustment comes with a compromise though, the closed loop dropout (with integrated tensioner) is heavier than limited adjustment open systems. Happy with the reliability of the first dropout system, this prototype aimed to shave 30% from the dropout weight. This would be achieved largely by reducing the size of the plate system and refining the disk adapter.

With a number of after market BMX disc adapters snapping during the 2019 season, there is a fine line between lightweight and reliability. On the first KW01 frame we erred on the side of caution with a slightly over engineered adapter that was bulletproof but a little heavy. The latest test frame removed excess material from the calliper mount and increased the dropout contact area. At a stroke reducing weight and improving strength in the area of greatest force.

Pushing past the limit

The more radical step was to reduce the material on the lower surface of the dropout, not only to save weight but also to allow easier adjustment of the chain tensioner. This is where we pushed the envelope too far. Under heavy breaking the rotational force was too great and the lower side of the dropout bent under the pressure. This is why we test. To find the ultimate balance between performance and reliability.

A wise man once said 'I never lose, I either win or I learn' well today was one of those days for Gate8's testing of the KW01. Far from being back to the drawing board we are able to move forward with confidence in a number of positive changes that further refine what was already a solid race frame.

Armed with this new data we’ll reinstate the lower dropout material on the production KW01 race frame. Also staying will be the shorter back end. Shortening the chain stay 5mm to the original 380mm allows us to move the seat stay the weld to the top of the dropout, further strengthening the dropout at the point of flexion yet allowing the rider to adjust their personal set-up from a not insignificant 370mm to 390mm.

The net result of today's test was an 18% dropout weight saving against the target of 30%, not as much as we'd hoped, but still a significant gain.

Staying In: Lighter disc brake adapter, refined dropout plates, revised seat stay tube set, enhanced cable routing, larger chain stay bridge, new chain stay bends
Going Out: Longer rear end, lighter dropout system.
Coming Back: Original dropout system

Next up - Full Race Test

The KW01 is scheduled for a full race test when Miguel will be giving the frame it's inaugural competitive run at the indoor race in Saint-Étienne next week. Assuming the race test goes as planned, we’ll be producing a pre-production range for the 2020 team frames during December for wider field testing early in the New Year.

Check back for Miguel's race test report later this month.