Spitfire Formula Four 101A Lock-Ins Wheels 55mm are Formula Four 101A wheels in the Lock-Ins shape, built for locking into grinds. Formula Four 101A is Spitfire's hardest duro, built on proven Formula Four performance for a harder, faster ride and extra speed.

At 55mm x 35.9mm, with a 23.5mm riding surface, this size adds a little speed and roll for park and transition. Sold as a set of 4.

Who These Wheels Are For

• Skaters who want locking into grinds
• Park and transition skaters
• Skaters on smooth spots who want max speed
• Spitfire fans

Features

• Formula Four 101A urethane
• Formula Four urethane: unmatched flatspot resistance and smooth anti-stick slide, per Spitfire
• Lock-Ins shape
• 55mm diameter, 35.9mm wide, 23.5mm riding surface
• Set of 4

Benefits

• Maximum speed on smooth surfaces
• Locking into grinds
• This size adds a little speed and roll for park and transition

Specs

Compare Formula Four 101A Lock-Ins Sizes

Every size in this line uses the same formula and shape.

Lock-Ins in Other Durometers

The same Lock-Ins shape in a different formula or durometer, in this size or the closest one available.

Complete Your Setup

New wheels deserve fresh bearings. Spitfire makes three tiers:

• Spitfire Cheapshots Bearings (Good): Spitfire's base-level bearing, tested by the pro team, with removable black shields to keep the crud out.
• Spitfire Classics Bearings (Better): Superfast and durable, with heat-resistant chromium steel rings, removable nylon cages, and blue removable shields.
• Spitfire Burners Bearings (Best): Spitfire's high-performance pick, with polished honed races and high carbon chromium steel, packed in a reusable tin.

FAQ

Is 101A hard or soft?

Hard. 101A is Spitfire's hardest duro, for extra speed on smooth surfaces.

What is the Lock-Ins shape good for?

Locking into grinds. Spitfire describes it as an asymmetrical shape with a conical cut profile on one side and a straight-edge lock-in cut on the other.

What size wheels should I get?

Smaller wheels (50 to 52mm) are light and technical, 53 to 54mm is the street and park go-to, and 55mm and up adds speed for transition and rough ground. See our skateboard wheels guide for more.