September 24, 2026

JConcepts BK Design 13mm Shock Pistons

A project from Brian Kimwald himself, BK Design Shock Pistons are now available as an option for 13mm shocks through JConcepts.  The BK piston, machined in low friction Delrin material has opened a can of goodness racers have only heard about, until now. The prototype slotted piston, machined by BK using equipment purchased exclusively for the master of all RC trades, was for sure a late-night project. During 2016, finding grip with newly released mid-motor vehicles was a vicious hunt for low-traction dirt conditions. As track conditions advanced, finding grip wasn’t necessarily as high a priority, hence the delay in the BK piston introduction. However, as the hands of time move forward, vehicles are once again looking for an edge in grip handling due to their advanced corning abilities. The all-precision machined item has the makings of the latest winner from the JConcepts Speed Laboratory and can be tuned by the user. The latest BK pistons arrive with plenty of pre-drilled combinations.  Test drivers have reported increased vehicle grip while utilising the exclusive design. The BK channel in the piston increases the volume of oil in the shock body acting as another chamber in the shock body to add consistency to the mechanism. During compression and rebound, a lot of disturbance is created inside the working area of the shock.  The action of a traditional piston is very top to bottom with pass-through only allowed through dedicated holes and around the perimeter due to blow-by.  With this design, the piston is passing fluid through 2 separate channeled sections while the entire disturbance area rests in oil which helps compartmentalise all activity.

Size options available
5327     JConcepts – 13mm shock pistons, BK design 2 x 1.5mm
5328     JConcepts – 13mm shock pistons, BK design 2 x 1.6mm
5329     JConcepts – 13mm shock pistons, BK design 2 x 1.7mm
5330     JConcepts – 13mm shock pistons, BK design 2 x 1.8mm
5331     JConcepts – 13mm shock pistons, BK design 2 x 1.9mm
5332     JConcepts – 13mm shock pistons, BK design 2 x 2.0mm
5333     JConcepts – 13mm shock pistons, BK design 3 x 1.5mm
5334     JConcepts – 13mm shock pistons, BK design 3 x 1.6mm
5335     JConcepts – 13mm shock pistons, BK design 3 x 1.7mm

Source: JConcepts [jconcepts.net]



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