Summary: Why the 75mm ?

In karting, the choice of the length of the hub (here 75 mm) directly influences the leverage exercised on the axle. A longer hub (75 mm versus 40 mm) changes the rear train rigidity and expands the path without necessarily using spacers. For the mini / cadet categories (25 mm axle), it is a centerpiece to find the good compromise between grip (adhesion) and curve passage speed.

- Technical specifications

- Mounting tutorial: precision and stability

The passage to 75 mm requires a little more care at the editing than the 40 mm, because the cantilever is more important.

1. Preparation: Clean the axle area perfectly where the hub will be positioned. Use very fine sandpaper (grain 600 or more) if you see traces of oxidation, then degrease.

2. Setting up: Slide the hub on the axle. If it strengthened, never type with a hammer. Check that there is no burr on the axle key.

3. Tightening (crucial): * Position the hub to the desired width.

   • Tighten the bolts alternately (up / down) to balance the tightening pressure.

   • Do not block dead: Aluminum is tender. Excessive tightening deforms the hub, and it will become impossible to adjust or remove the next time without forcing.

4. Verification: Once tight, rotate the wheel by hand. It must not present any "veil" (lateral oscillation).

💡 Michel's trick

"There is a difference in important behavior between a 40 mm hub and a 75 mm. The trick: With a 75 mm hub, you increase the lever arm on the axle. If your chassis 'jumps' or locks in the corner, iron on shorter (40 mm) hubs to soften the rear yard. Conversely, if your kart lacks output motricity, the 75 mm can help load the outside more. My Pro Council: Always keep a pair of 40 mm and a pair of 75 mm in your crate. The change is done in 5 minutes on the pre-grid, it is one of the most effective settings for adapting to the evolution of the track. "

❓ FAQ SEO (Frequently Asked Questions)

Q: Does a longer hub weaken the axle ?

A: Yes, the 75 mm hub exerts a lever arm more important than a 40 mm. It is a little more demanding for the axle. Check regularly that the hub clamping screws do not take a game.

Q: Can we mix a hub of 75 mm on the left and a 40 mm right ?

A: It's very advised against. This would create a dangerous mechanical dissymmetry in the behavior of the kart (the difference in flexibility on each side). Still symmetrical.

✅ Ready for your settings ?

Your chassis configuration is taking shape. To finalize your rear train:

• [Essieu 25mm CRG] (If you need to change the diameter or rigidity).

• [Écrous de jantes] (If your current nuts are blunt)