Seismic: Defcon Standard-Barrel Bushings

Seismic® Defcon™ Barrel Bushings
Deeper Lean with Truer, More Fluid Steering • Finer Control and Highly-Energetic Response • Precision Fit
Available in eight (8) color-coded durometers and three (3) precision-fit heights.
Price is for a single pair of two (2) barrel bushings. Discounted pricing for Bundles of five (5) pairs in 81A through 93A (all in a single height).

Seismic’s Defcon ultra-high-rebound urethane has a remarkable set of unique and highly-advanced properties – and now we’ve applied it to bushings! Defcon is the fastest wheel formula in the history of skateboard racing – credited with virtually every significant world distance and speed record, including the official Guinness Standup mark. (Pete Connolly, 91.17 mph / 146.73 kph – Sept. 16, 2017, at The Top Speed Challenge in Quebec, Canada.)

A major step forward in bushing performance…
• Deeper lean and truer, more fluid steering with less lateral hanger slop!
• Smoother, more linear resistance profile – Consistent feel • Advanced control
• Very calm and predictable at speed compared to other bushing formulas – Not bouncy, nervous, or twitchy
• Highly-energetic yet smooth and controlled return-to-center
• Larger compression range compared to other bushing formulas in the same duro – No premature packing • Fuller wheel contact (less “outside wheel lift”)

Fine-tuned dimensions for high-performance fit!
• Full 1.0-inch outer diameter optimizes seating in bushing pockets of finer modern hangers.
• Inner diameter carefully calibrated for snug fit on standard kingpin shafts.
• Mold-top ends machined for exact height and superior flatness. – No “dished” end surfaces.

Three (3) precision-fit heights…
• Standard 0.60-inch (15mm): Optimal height both Board-Side (BS) and Road-Side (RS) for many modern longboard trucks, especially those assembled with BS washers. (e.g., Bear, Caliber, Paris, Dont Trip Poppy / Slalocybin)
• Medium 0.65-inch (16.5mm): Optimal height both BS and RS for brands including Aera, Carver, and Sabre. Also fits well both BS and RS in many modern trucks where BS washers are optional or omitted. (e.g., Dont Trip Poppy / Slalocybin) If paired with a shorter bushing, fits well in many trucks assembled with BS washers. (e.g., Bear, Caliber, Paris) Fits same trucks both BS and RS if BS washer is removed.
• Tall 0.75-inch (19mm): Optimized fit both BS and RS in many modern race trucks. (e.g., Exile, Rogue, Ronin, Skoa, Valkyrie, Zealous, Dont Trip Boomer / DH-Cybin / Haki / Molly) Also fits BS in Caliber trucks if shim is removed.

Finer points on bushing fit
• Every truck design has unique bushing fit patterns. From one brand to another, and even among different models from a single brand, the variations are dizzying in number and daunting to track.
• Many trucks assembled with BS washers (e.g., Bear, Caliber, Paris) perform well with one Medium bushing (either BS or RS), as long as it’s paired with a second bushing that’s shorter. Some truck models (e.g., Bennett, Dont Trip Bhanger / Delirium) are designed to take Tall BS bushings and shorter RS bushings. Still other truck models can accommodate either Standard or Medium bushings both BS and RS.
• Optimal bushing height depends partly on whether the truck assembly includes a BS washer, which takes up 1.5mm – 2.0mm of the linear space available for bushings on the kingpin shaft. (The RS washer, normally placed between the kingpin nut and the RS bushing, takes up an equal amount of linear space.)
• Trucks whose baseplates have a narrow bushing platform usually perform best with BS washers, which improve bushing support at the BS interface. Trucks whose baseplates have a wider bushing platform often perform equally well (or better) without BS washers.
• Kingpin length also plays a role. Trucks with longer kingpins can accommodate a wider range of bushing heights; trucks with shorter kingpins are only compatible with a narrow band of bushing heights. For this reason, older Paris-brand trucks (with longer kingpins) accommodate taller bushings than newer Paris-brand trucks (with shorter kingpins).

Bushing fit hacks
• If your bushings seem too tall for your trucks, try sanding on grip-tape to reduce their height.
• Certain older truck designs (e.g., GOG, Randal, Bear prior to Gen 6) have hanger bushing pockets that are tight on Defcon bushings’ true 1.0-inch outer diameter. To ease fit in these cases, try sanding bushing edges on grip-tape to add radius.

Note: Defcon bushings may feel slightly softer than comparable duros from other brands using more basic urethane formulas. For optimal bushing performance, do not under-tighten or over-tighten kingpin nuts. Replace bushings that show signs of excessive wear, weathering, or aging.