75.5mm Seismic Alpha Defcon Chase Hiller Pro Longboard Skateboard Wheels

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(1 review)
  • Diameter: 75.5mm
  • Durometer: 74a
  • Width: 62.5mm
  • Contact Patch: 62.5mm
  • Lip Profile: Square
  • Core Placement: offset 6.5%
  • Wheel Surface: Smooth
$97.00 USD
1 Quantity = 4 Wheels, enough for a complete longboard.

The 75.5mm 74a Seismic Alpha Defcon Chase Hiller Pro longboard wheels were designed for maximum roll speed on smooth and rough surfaces with extra edge hold. Racers or riders that aim for speed will find what they are looking for in the new Alpha Defcon formula.

Defcon Formula and the Fushion Core explained in more detail by Seismic Team Riders:

The 75mm x 62.5mm Alpha Race Wheel
Stout S-shaped lip profile optimizes edge support, maximizes edge-hold under extreme G’s, and ensures predictable slide initiation & hookup
0.5mm concave running surface pre-loads lips, heightens rebound, and enhances in-slide feedback
6% offset for progressive lip engagement and more consistent wear

Debuting Seismic's proprietary Fusion Core!
Measures a whopping 46mm x 44mm – making it the largest & most supportive hub on the market for a wheel of this size!
Deep “saddle” profile minimizes lateral wheel flex and creates outstanding mechanical lock w/urethane
Unmatched edge support
Robust bearing lugs
Fiber-reinforced 85D – the strongest, toughest hub material in the industry

Guinness WR roll speed
Directional slide
Long-lasting grip
Slow, consistent wear

Seismic's Description

A perfect balance of optimal properties for modern competitive racing: size and momentum to carry you past the competition in straightaways; finely-tuned width and supremely supported edges for smooth, predictable handling through even the hardest corners; and the very fastest urethane that the skateboard industry has ever seen, bar none.

Defcon™: Guinness WR speed • directional slide • long-lasting grip • slow, consistent wear

A giant step forward in race wheel engineering. The Alpha’s stout S-shaped edge profile optimizes lip support, maximizes traction under extreme G’s, and ensures predictable slide initiation and hookup. The running surface features a 0.5mm concave that pre-loads the edges, heightens rebound, and enhances in-slide feedback. The bearing seat is offset 6% for progressive lip engagement and more consistent wear.

The Alpha™ also marks the debut of Seismic’s proprietary Fusion™ core – at 46mm tall x 44mm wide, the largest and most supportive hub ever seen in a wheel this size. Features include a deep “saddle” profile, 8 perpendicular support beams (hollowed-out for lightness and aesthetics), and robust bearing lugs. The Fusion minimizes lateral wheel flex, supercharges edge support, and assures absolute mechanical lock with the urethane. Formed from 85D fiber-reinforced thermoplastic – the toughest hub material in the industry.

75.5mm tall x 62.5mm wide ALPHA Wheels
62.5mm running surface • Bearing seat offset 6% • Square outside edge, straight-cut inside edge
8.125 oz. each • Sold in sets of FOUR wheels


Best race wheels I've ridden
on 2021-05-06 Verified Purchase
These are so dank. This 74a defcon, with the alpha core, is the best iteration of defcon urethane I've skated, and defcon is already my favorite thane. They are 98% as fast as the harder duros, but grip harder, have significantly more edge feel, slide smoother, AND slow you down more????. I don't know how they do it. Plus, they're quite soft, and roll really quiet and comfortable. I skated them fresh on a big tailwind day at Maryhill and they were perfect, and even after they scrubbed out, they kept a good enough edge to be confidence-inspiring. Since then I've skated some ~35-40mph open roads, some fun neighborhood runs, and some tight and technical bike paths. They really do it all, and they slide nice on almost all the pavement I've tried them on. Being a super soft, super high rebound urethane, they will chunk easily if you slide into gravel or hit a sharp edge the wrong way. But I've been careful with my set, and they've worn really nice and consistently and still have most of their original edge. Pretty impressive for a 74a wheel and definitely has a lot to do with the massive alpha core supporting the lips.