Built Around the Right Weight — Not the Heaviest.
Factory engineers tune shift feel carefully. OEM knobs aren't heavy because heavy is good — they're a specific mass chosen for the transmission, the lever geometry, and how a hand wants to work them. Heavier isn't always better.
ShiftMass was built on a different idea: the right weight is personal, and it's tunable.
The Weight System
The Apex Head sits at 120g — the lightest of the three launch heads. An extended profile wrapped in hand-sewn Charcoal Alcantara, framed top and bottom with anodized aluminum caps. Choose your cap color to accent the wrap.
Three brass rings (18g / 30g / 52g) thread onto the base and lock together with brass-on-brass friction — no set screws, no loose hardware. Position them anywhere along the shaft.
Eight weight settings from 148g unloaded to 248g fully loaded:
- 148 g — unloaded
- 166 g — + 18g
- 178 g — + 30g
- 196 g — + 18g + 30g
- 200 g — + 52g
- 218 g — + 18g + 52g
- 230 g — + 30g + 52g
- 248 g — all three rings
Install once: thread the base onto your factory M12x1.25 shifter, align the head, and lock with the stainless set screws. From there, heads and weights swap by hand.
Fits the Standard Reverse Lockout
Machined to clear the factory reverse lockout collar on Subaru WRX, STI, BRZ (Gen 1), Scion FR-S, Toyota 86/GT86, and related 6MT platforms. No adapters, no shimming.
If you have a 2022+ Subaru BRZ or Toyota GR86, you want our Large Lockout version instead — same product, tuned for the larger factory lockout collar on Gen 2 cars.
Three Heads at Launch
- Orbit — 128g, round profile, anodized aluminum
- Apex — 120g, extended profile, Alcantara wrap (this product)
- Arc — 146g, contoured profile, Alcantara wrap
Coming Soon
- Track Edition — 90g hollow, OEM-close feel
- More head profiles in development — sign up on the email form to hear first
One base. One ring set. Any head. Your feel, your car, your range.
What's Included
- ShiftMass™ Apex Head (finish of your choice)
- Weight-adjustable Base with Standard Lockout cavity (finish of your choice)
- Brass weight ring set — 18g / 30g / 52g
- Stainless set screws & Allen key
- Printed setup instructions
Built entirely in a small USA machine shop in Texas
- 6061-T6 aluminum with a solid brass tunable weight system
- M12x1.25 direct-fit threading — no adapters
- Standard ~22mm internal cavity for factory reverse lockout fitment
- Head finish: Charcoal Alcantara wrap with anodized aluminum caps in Polished Black, Brushed Gold, or Brushed Grey
- Base finishes: Gloss Black / Brushed Gold / Brushed Grey / Natural
- Designed, machined, and assembled in-house
- Compatible with all current and future ShiftMass™ heads
Not sure which fits your car? Check the fitment guide below, or message us with your vehicle — we'll verify before shipping.
Street Machine Works
