Tuning Your RC Car with Wheel Hexes: A Guide to Track Width Adjustments

By Jacob Hardison | Adrenaline RC Racing

If you’ve spent time tuning your RC car, you’re probably familiar with adjusting track width using your A/B and C/D blocks. But what if you’re looking for a more subtle tweak? That’s where wheel hexes come in. In this post, we’ll break down how different hex widths can fine-tune your setup, giving you more control over front and rear grip without drastically altering your suspension geometry.

What Are Wheel Hexes?

Wheel hexes are the small aluminum or plastic parts that sit between your wheel and axle. They come in varying thicknesses (like +0, +1, +2, +4, etc.) and can slightly increase or decrease the overall width of your car. While not as dramatic as pivot block adjustments, swapping hexes is a quick way to gain or reduce traction—perfect when you're chasing that last bit of lap time or fine-tuning your car for specific track conditions.

Front Hex Tuning: Grip vs Stability

Let’s start with the front of the car:

🔹 Wider Front Hexes (e.g., +3 or +4)

• Effect: Decreases front grip

• Result: Slower steering response, more stability

• When to Use: On high-grip tracks, bumpy conditions, or large sweeping layouts to avoid traction rolling

🔹 Narrower Front Hexes (e.g., +0 or +1)

• Effect: Increases front grip

• Result: Faster steering response, more aggressive front end

• When to Use: On low-grip surfaces or tight, technical tracks where you want quicker turn-in

👉 Quick Tip: A narrower front makes the suspension feel "softer," increasing chassis movement and response. A wider front feels "stiffer," reducing sensitivity but adding control.

Rear Hex Tuning: Drive Out of the Corner

Now let’s talk about the rear:

🔹 Wider Rear Hexes

• Effect: Reduces rear grip, makes car more stable mid-corner

• Result: Can cause less rear traction on throttle

• When to Use: High-speed, high-grip tracks or extremely bumpy surfaces to help the rear “flow” rather than catch

Bonus: Removing rear grip can make the front feel more aggressive—so if your car feels too lazy up front, a wider rear hex might help.

🔹 Narrower Rear Hexes

• Effect: Increases rear grip, softer suspension response

• Result: More traction coming out of corners

• When to Use: Low-grip tracks where the surface isn’t helping you generate grip naturally

🚨 Caution: Running hexes that are too narrow on high-speed or high-grip tracks can make your car feel twitchy or unstable. Balance is key!

When Should You Swap Hexes?

Here’s a cheat sheet:

Final Thoughts

Swapping wheel hexes is a quick, effective way to dial in your RC car without overhauling your entire setup. Whether you're trying to fine-tune steering response or balance grip front to rear, changing hex widths can make a noticeable difference on the track.

Have questions about tuning or which hexes to try for your setup? Drop them in the comments on our YouTube video or stop by the shop—we’re always here to help.

Stay fast,
Jacob Hardison