WORKS BELL RAPFIX Racing Weld-on type

Manufacturer: WORKS BELL
Product name: RAPFIX Racing, weld-on type

• Intended use: competition vehicles only
• Steering wheel fitment: competition type (PCD 50.8 mm, 3 holes, M5 × P0.8)
• Vehicle mounting: welded (pipe diameter φ19.0 outside or φ25.2 inside)
• Main materials: plug – chrome molybdenum steel SCM435; socket – aluminium alloy A7075T6; sleeve – aluminium alloy + stainless steel SUS420; balls – SUJ2 steel
• Dimensions: overall length approx. 90 mm
• Weight: 354 g

Background

Developed as the ideal competition quick-release hub. The RAPFIX range had already sold over 20,000 units as a removable hub for aftermarket sports steering wheels, and its distinctive Ball Lock System made RAPFIX synonymous with the quick release. Building on that technology, this version was made smaller and lighter specifically for competition cars.

Features

Pull the sleeve and the steel balls inside the socket are freed, letting the socket separate from the plug. The sleeve stays held in the pulled position, so you do not need to pull it again when refitting. It can be inserted at any angle and engages automatically once the steering wheel (socket) and steering shaft (plug) line up – a major advantage that does away with the old quick-release annoyance of having to find top dead centre exactly before the shaft would go in.

Thanks to a proprietary design, the steel balls maintain constant pressure against the plug, so there is no play and steering force is transmitted with certainty. This combination of zero play and smooth engagement holds up even after a degree of wear, which makes a real difference to precise steering inputs at the limit.

For absolute reliability in racing, RAPFIX Racing also adds a new “cam lock” mechanism that positively locks radial loads once the plug and socket are fully engaged. Together with the ball lock, it guarantees safety.

Design details

Developed on the assumption of competition use. The plug is chrome molybdenum steel SCM435 so it can easily be welded to the steering shaft; the sleeve uses a SUS420 liner internally for light weight combined with high strength. The socket is super duralumin with a special plating for durability. Anticipating hard use, the plug tip carries a Delrin resin protective cap – so even a careless insertion is unlikely to damage the socket, and the cap is easily replaced if it does get damaged. A bolt-on type that fixes to the steering shaft with bolts (PCD 50.8 mm, 3 holes) has also been added to the range.

Strength testing

Testing was carried out to the NAPAC standard (*1), the Japanese aftermarket product benchmark.

In those tests, both the bending and torsion tests produced slight permanent deformation at the specified load and an increase in play – but the unit could still be attached and detached afterwards, did not fracture, and was shown not to become unsteerable even under large loads. A further test measured the tensile load at which an engaged plug and socket would release: no failure occurred even at 3,754 kg (3.67 kN); the test ended when the screws fastening the steering wheel failed first, and the quick-release function was confirmed still operable afterwards. Since the Japanese Industrial Standards figure for a driver’s standard body weight is 55 kg, this equates to withstanding roughly 68 G of impact in the tensile direction.

For durability, an in-house test of 10,000 attach/detach cycles confirmed that although play increased, the unit remained steerable and operable and did not fracture.

(*1) For transmission of steering force and radial loads, the torsion test requires no failure under a static load of 29.7 kg·m (291 N·m). For bending loads such as the driver’s body weight acting on the top of the steering wheel, the bending test requires no failure under a static load of 19.8 kg·m (194 N·m).

Important – please read before purchasing

This is a competition-only product. Please note the following:

• It is NOT Japanese road-legal (not shaken compliant).
• MOMO and NARDI horn buttons cannot be fitted.
• It cannot be fitted directly to standard PCD patterns (MOMO 70 mm, NARDI 74 mm). A 3-to-6 hole conversion adapter, sold separately, is required.
• It cannot be fitted directly to standard or short bosses. Please contact us for details.
• For all other product characteristics, shapes and mounting hole details, please review the instruction manual and product outline drawing and confirm your installation method before purchasing.

Please note: the steering boss is sold separately. A separate steering boss is required for installation.

If your order is urgent, please contact us before purchasing.

Lead time: Usually ships in 1–3 business days. If the manufacturer is out of stock, please allow approximately 1 month.