AE B4.2 / Kyosho RB6 / Misc / News / TLR 22

AE Machined 12mm Tapered Pistons!

Oh snap! I was hoping AE would release better pistons and here ya go! It  is always nice to see new tuning options besides the kit standard 2 hole variants. If it wasn’t already confusing to figure out a setup for your new BB’s shocks with 2 holes…here’s adding more to the fire! It’s going to be interesting to see which piston is going to be the “ONE” piston for the 4.2. Here is the post straight from AE’s website.

 ae pistons

New Factory Team machined pistons for the 12mm big bore shocks take performance to the next level.
Precision CNC machined pistons allow for the best fitment and concentricity with the shock body to improve handling and consistency. The new pistons are also tapered for independent tuning of compression and rebound.


  • Compression movement: Shock piston traveling upward toward the top of the shock
    Rebound movement: Shock piston traveling downward toward the bottom of the shock
  • Tapered piston: One side of the piston face is flat; the other is tapered / angled
    Flat piston: Top and bottom of the piston face are flat

Difference between tapered and flat pistons

  • A flat piston will travel at the same speed in compression as it does in rebound (given equal force is provided in both directions)
  • A tapered piston will travel faster in the direction of the taper/angle.

For example, a tapered piston with the taper facing down will travel faster in rebound than it will in compression, allowing the user to tune the rebound and compression movement independently.

tapered piston illustration

Piston Hole Size

  • Larger holes allow more fluid to pass through the shock piston, which allows the shock to move faster.
  • Smaller holes will have the opposite effect, causing the shock to move slower.

Piston Hole Count

By changing the number of holes in the piston, a similar damping level can be achieved with different amounts of “pack.” Pack is the feeling of hydraulic lock in a shock when the fluid flowing through the holes reaches a certain speed. It can be used to keep a car from bottoming out during harsh landings.

Part No. # Holes Hole Dia. Qty Included Piston Shape Piston Marking
#91346 2 1.5mm 4 tapered 1 Dot
#91347 2 1.6mm 4 tapered 2 Dot
#91348 2 1.7mm 4 tapered 3 Dot
#91349 3 1.4mm 4 tapered 2 Dot
#91350 4 1.3mm 4 tapered 2 Dot

#91346 FT Tapered Piston, 2 x 1.5mm holes
UPC: 7 84695 91346 2

#91347  FT Tapered Piston, 2 x 1.6mm holes
UPC: 7 84695 91347 9

#91348 FT Tapered Piston, 2 x 1.7mm holes
UPC: 7 84695 91348 6

#91349 FT Tapered Piston, 3 x 1.4mm holes
UPC: 7 84695 91349 3

#91350 FT Tapered Piston, 4 x 1.3mm holes
UPC: 7 84695 91350 9

#91308 Standard Flat pistons, two-hole (1.5mm, 1.6mm, 1.7mm)
UPC: 7 84695 91308 0

Original source courtesy of Team Associated.

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