GT 300 mm vs GT 300 mm Wheel Rim: Which Size Suits Your Rig?

Quick answer

The GT 300 mm Wheel Rim is the better pick if you want a round, 300 mm GT-style rim that works with the GSI Interlock system or any 70 mm PCD button box, and you plan to add paddles, clutches, or an LED matrix over time. The GT-MAX32 suits drivers who want a molded carbon fiber wheel with over-molded silicone grips and are ready to commit to GSI's ecosystem. Both are 300 mm, so the real decision is modular flexibility versus an integrated, lightweight build.

What the 300 mm diameter actually changes

A 300 mm rim sits between a smaller formula-style wheel and a larger 320 mm round wheel. The smaller the diameter, the less your hands travel to reach lock, which can make quick corrections feel more immediate. A larger 320 mm rim gives you more leverage and a slightly calmer feel at the limit, which some GT and rally drivers prefer for long stints.

Neither size is universally better. The right choice depends on your seating position, the torque of your direct drive base, and whether you drive mostly formula, GT, or rally cars. If your rig has a tight cockpit and your wheel base sits close to your chest, a 300 mm rim is usually the safer fit. If you have a more upright GT seating position with room to spare, a 320 mm rim can feel more natural.

GT 300 mm Wheel Rim: modular and broadly compatible

The GT 300 mm Wheel Rim is built on a rigid alloy core, which GSI says provides a stable platform for precise control and accurate force feedback response. The motorsport-inspired shape supports natural ergonomics for long sessions, and the 70 mm PCD bolt pattern makes it compatible with the GSI Interlock system as well as sim racing button boxes that use the same pattern.

That 70 mm PCD compatibility is the practical advantage. You can mount this rim to a wide range of button boxes and GSI's Interlock base module, then add paddle shifters, clutches, or the LED Matrix as your needs change. If you are still deciding on electronics, this rim lets you start simple and upgrade later.

GT-MAX32: integrated carbon build with silicone grips

The GT-MAX32 takes a different approach. GSI describes it as a first for sim racing steering wheels: a continuous molded carbon footprint where the face and outer circular rim are a single carbon fiber unit. The handles are over-molded in silicone for maximum grip and strength while reducing weight.

That construction reduces the number of seams and joints you would find on a bolted-together wheel, which can translate to a stiffer, lighter feel in your hands. The trade-off is that the GT-MAX32 is a more committed purchase. It is available in color and configuration options, but it does not offer the same swap-and-upgrade modularity as the GT 300 mm rim. If you like to change rims or button boxes frequently, the GT 300 mm rim is the more flexible path.

How to choose between them

Start with your rig's geometry. Measure the distance from your wheel base to your chest in your normal driving position. If that distance is short, a 300 mm rim is easier to live with than a 320 mm wheel. If you have a longer reach and a GT-style seating angle, either 300 mm option here will work, and you can choose based on build and upgrade path rather than size.

Next, decide whether you want a system or a single wheel. The GT 300 mm Wheel Rim is part of the Interlock ecosystem, so it pairs with the Interlock Base Module + Rim bundle and accepts paddle shifters, clutches, and the LED Matrix. The GT-MAX32 is a self-contained molded carbon wheel. Neither is wrong; they simply serve different upgrade philosophies.

Finally, consider your base. A rigid alloy core and a molded carbon unit both handle direct drive torque well, but the lighter GT-MAX32 may feel slightly more responsive if you run high torque settings. The GT 300 mm rim's alloy core gives you a stable, familiar platform that many drivers find easier to trust when switching between cars.

Trade-offs at a glance

• GT 300 mm Wheel Rim: Rigid alloy core, 70 mm PCD, works with Interlock and third-party button boxes. You can add paddle shifters, clutches, or the LED Matrix later. Choose this if you want modular upgrades and broad compatibility.
• GT-MAX32: Continuous molded carbon fiber face and rim with over-molded silicone grips. Lighter and stiffer, but a more integrated, less modular purchase. Choose this if you want a lightweight, self-contained wheel and do not plan to swap components.
• Diameter: Both are 300 mm. If you want a larger 320 mm wheel for more leverage, neither of these is that size. Confirm your seating position and reach before buying; 300 mm is not the same as 320 mm.

Product facts

• GT 300 mm Wheel Rim: Engineered on a rigid alloy core, every GSI wheel rim provides a stable platform for precise control and accurate force feedback response. The motorsport-inspired shapes support natural ergonomics, making it well-suited for long sessions and consistent performance. Compatible with the GSI Interlock system as well as sim racing button boxes that use a 70mm PCD bolt pattern. The 70 mm PCD pattern means you can mount this rim to a wide range of button boxes and GSI's Interlock base, so you are not locked into one electronics platform.
• GT-MAX32 + Simucube 2 Pro Bundle: The GT-MAX32 takes everything we've learned and elevates to a new level of technology including features, construction and assembly. A first for sim racing steering wheels, the GT-MAX32 is made from a continuous molded carbon footprint. The face and the outer circular rim are a single carbon fiber unit with handles over-molded in silicone for maximum grip and strength all while reducing weight. The single-piece carbon construction and silicone grips reduce weight and eliminate seams, which can feel stiffer and more direct in your hands than a bolted-together wheel.
• Interlock Base Module + Rim / Blackout + Simucube 2 Pro Bundle: The Interlock Base Module + Rim is the most straightforward way to start with Interlock. You'll get the modular core paired with a GSI rim, with the option to add paddle shifters, clutches, or the LED Matrix. Every piece is designed to work together, so your setup can grow over time. If you choose the GT 300 mm rim, this bundle is the simplest way to get the modular core and a rim together, with a clear upgrade path for paddles, clutches, and the LED Matrix.

Which one fits you?

Best for

• Drivers who want a 300 mm GT-style rim they can mount to a GSI Interlock base or a 70 mm PCD button box
• Sim racers who plan to add paddle shifters, clutches, or an LED matrix over time
• Anyone who wants a rigid alloy core and a familiar round-rim feel for long sessions

Not for

• Drivers who specifically want a 320 mm wheel for more leverage and a calmer feel
• Sim racers who want a single-piece molded carbon wheel with silicone grips and do not need modular upgrades