Bike Check: AirDrop's Prototype Filter 4X Bike

But like all good ideas this one didn't die. It was there hiding in the shadows waiting for the opportunity to present itself when it could come to the fore. Now this wasn't in the form of a 4X race, instead it was apt, as Airdrop are a Sheffield brand through and through, that it was built for Peaty's Steel City race. It's clear that this bike was too good to end up just on the wall so it's ended up with Dan to not only race National Championships on it (in which he came 5th) but also finish out the UK season alongside the 4X Pro Tour round in Val di Sole. It will be amazing to see this bike get the chance to do what it was built for: battling it at the highest levels of 4X racing.




The main change from the Filter trail bike (that's available right now) and this prototype 4X version is sizing; this sits right between the currently available small and medium. It's still running a 150mm travel fork out front with 135mm of rear travel with a few extra tweaks made to them.


The frame design is beautiful, simple and clean. It has standard bearings used in all its pivots and has external cable routing with a threaded bottom bracket to make working on the bike as simple as physically possible.




In its trail bike configuration, the Filter runs 135mm travel out back. That's with a 185x55mm shock. You can get 50mm stroke shocks in the same size which would deliver 122mm travel, and given that for 4X large amounts of rear travel aren't needed, Airdrop thought about going down that route. Coupling that with Rockshox MegNeg air can with higher pressure would be the dream setup. However, in the end due to budget constraints, it was decided to opt for the 185x55mm standard Rockshox Super Deluxe with all of the tokens in it. There is 215psi of air in it and the rebound is set from 8 clicks from its slowest setting.



Fitted up front is a RockShox Pike Ultimate at 150mm. This is to preserve the head-angle and front-end height, but once again with all the tokens fitted in the air chamber to get a bit more progression. There is 97psi in the pikes and the rebound is set to 5 clicks from its slowest position.


For wheels, there is a workhorse set of Hope Fortus 35's running Hope's Pro 4 hubs. Wrapped around the Hope rims are a set of Michelin Wild Enduro 2.4 tyres which are running tubeless. Dan was running 27psi in the front tyre and 30psi in the rear.



It's a full SRAM groupset on Dan's Filter 4x. With SRAM's GX DH groupset installed including the 7-speed cassette and a super nice KMC gold chain.


There's more from SRAM's GX range with a set of its aluminium cranks installed with a DMR Blade 34t chainring mounted. The chain is kept in place by the E*thirteen TRS chain guide with a top guide and lower bash guard. Like all 4X racers it's clip pedals for Dan with a set of HT's X2's fitted here.



Nice little race touches with grip tape added to the SRAM GX shifter for the extra grip when you need it.


Some old brakes are fitted but if they work they work. It's more SRAM here with their Avid X0 Trail brakes being used with a set of SRAM 160mm discs front and rear.



Burgtec provides the bar and stem combo on Dan's bike. For bars there is Burgtec's Ride High Josh Bryceland Signature alloy handlebar cut to 780mm wide with 50mm rise mounted to a Burgtec Enduro MK3 stem and finished off with a set of DMR Deathgrips. The Burgtec parts don't stop there, with the UK brand also providing its Cloud Boost saddle.


A massive thanks to Dan and to Airdrop for their help putting this together.

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Reviews and Tech Bike Checks Enduro Bikes Airdrop Airdrop Filter