Bosses (steering hubs) are necessary for steering wheel replacement.
This time, we actually compared three standard Japanese products – Daikei, Works Bell, and HKB SPORTS (Toei Sangyo).
Although we had already decided which manufacturer to use, it was interesting to see the differences between the three companies highlighted once again in this side-by-side comparison. This time we compared them for the NB Roadster, but the differences would be the same for other types of vehicles as well.
📦 Measured Comparison
| Product | Length | Weight (including cover + wiring) |
|---|---|---|
| Daikei S-606 | 80 mm | 441 g |
| Works Bell 910 | 75 mm | 534 g |
| HKB SPORTS OR-230 | 90 mm | 270 g |
respectively, with Daikei on the left and Works Bell on the right
🛠 Steel vs. die-cast aluminum with surprising consequences
It is generally believed that aluminum is lighter and iron (steel) is heavier, but this comparison overturned that conventional wisdom.
Daikei’s boss, although made of steel, was the lightest due to design and processing that took advantage of the strength of the material. On the other hand, the Works Bell boss is the heaviest, despite being made of die-cast aluminum, and its entire structure is thick and sturdy. Even more interesting is the boss of HKB SPORTS. It, too, is made of die-cast aluminum, but its elaborate structure and small amount of cutting make it surprisingly light, about half the weight of Works Bell’s. In other words, it is not so much the difference in materials as it is the difference in design philosophy.
In other words, the difference in design philosophy and machining policy, rather than the difference in materials, is directly related to the difference in weight. Steel makes them heavy, aluminum makes them light – it is not that simple.
✨ Differences in texture, design, and finish
◼ Daikei S-606
- Spline part is machined, and drawn molded part and welding
- Many processes such as pressing, cutting, welding, and plating are involved and time-consuming
- Airbag canceller has a sense of reliability
- Resistors are housed in a case and connected with connectors
- Horn harness with protective tube
- Crystal painted like cover is extendable
- The instruction manual is 6 pages in B4 size, large format, and very helpful with many illustrations
- Half of the manual explains how to remove the factory steering wheel
- Note that the center nut must be removed without leaving it in order to prevent injury.
→ Overall, the product is “solid and solid”. I have the impression that these products are made with a lot of time and effort.
◼ Works Bell 910
- Accuracy is high, complex shape. Appearance is also well-defined.
- Casting holes of about 0.5φ can be seen in the cutting area.
- The airbag harness is covered with heat-shrinkable tubing, and the wires are thin.
- The bellows-style cover is cut and adjusted.
- Mounting nut included
- The instruction manual is A4 size, printed on both sides, with two pages per sheet, one for the front cover and one for notes.
- It was not expected that users could read this and install it, but it said to ask a specialized store to do so
→ Looks highly precise and chunky and heavy.
◼ HKB SPORTS OR-230
- High accuracy, complex shapes
- Many casting surfaces and few machined areas
- Airbag harness is exposed cement resistance
- Elaborately constructed sliding boot-type cover can be extended or retracted
- Non-rotating horn ring
- Mounting nut included
- Instructions are three small sheets of paper, but there is a note about pulling out the center nut without removing it.
🔧 Difference in tightening torque
The tightening torque for the center nut that tightens the boss to the steering shaft is specified as such.
- Daikei：4.5-5.0 kg-m
- Works Bell：2.5-3kg-m
- HKB SPORTS：3.5kg-m
- (Roadster manufacturer’s specification: 4.0-5.0 kg-m)
This difference clearly shows the difference in product strength. Works Bell and HKB SPORTS, both made of die-cast aluminum, are specified with weak tightening torques.
Works Bells may break even with the specified torque if the shaft taper is not degreased, and the use of the supplied nuts and spring washers is also specified. About Tightening Torques | Works Bell
However, I feel that it must be difficult to use die-cast aluminum to fasten the mating parts. We think that structural improvements should be made, such as using a casting material with higher ductility and toughness, or combining it with a steel sleeve.
🏭 Machined vs. die-cast: the difference in philosophy behind the products
◼ Daikei
- Structure: Steel + machined + welded structure
- Features: Not suitable for mass production, but accuracy, rigidity, and reliability are a cut above.
- Accessories: High quality harnesses and airbag cancellers, clear and detailed instruction manuals
- Weight: Steel construction makes it moderate
◼ Works Bell
- Structure: Die-cast aluminum molding + finish cutting
- Characteristics: Structure suitable for mass production by die casting. Although it has a sense of precision, it is thick-walled and heavy for its rigidity.
- Accessories: Airbag canceller and horn wiring are thin, and the instruction manual is minimal
- Weight: Shortest but heaviest aluminum product
◼ HKB SPORTS
- Construction: Die-cast aluminum, minimal machining
- Features: Optimized design, lightweight, least expensive
- Accessories: Airbag canceller and wiring are simple, instruction manual is also simple
- Weight: Lightest weight (about half of Works Bell)
✅ Conclusion: Daikei for strength, HKB for lightness
To begin with, the factory steering wheel is basically made of steel for all car models. Automobile manufacturers deliberately choose heavy steel for reasons of “rigidity, durability, and collision safety. This probably means that there are requirements in terms of safety and reliability that cannot be met by aluminum die-casting.
The explanation sometimes given for retrofit bosses made of die-cast aluminum is that they protect occupants by intentionally breaking in the event of a collision, but this is a subtle point: does the boss really need to be broken in the event of a collision? Daikei’s bosses do not appear to break, but they seem to comply with the “Safety Standards for Road Vehicles, Article 11 (gnawing devices).
In modern automobiles, the crushable structure around the steering shaft (column crush and tilt relief) is designed so that axial loads are absorbed on the body side. In other words, there is little technical basis for the claim that the boss breaks to protect the driver. The factory steering wheel does not break that easily. The boss, which is integrated to the mating part with the steering shaft, is considered to be a component for which die-cast aluminum is not suitable.
According to the actual measurement results, the aluminum die-cast Works Bell was heavier than the steel Daikei, which is understandable since HKB SPORTS is inexpensive and lightweight.
🧠 Showa in appearance, genuine in content.
Steel is the “lifeline” of the steering wheel.
Daikei’s boss is plain and unpretentious. The website has also been frozen in time since 2001. However, the contents of our products are of high quality that are not only acceptable in the modern age, but are still the standard.
That is why we choose Daikei for the most important performance features of reliability, precision, and rigidity. We choose Daikei not for the safety of breakage, but for the peace of mind that it will not break.
🖥️ Aside: A message from 2001, as if from 2001, the official website of Daikei Sangyo
Incidentally, you may be surprised if you accessed the official website (http://www.daikei-s.co.jp/) while researching information on this Daikei steering boss.
Shift_JIS encoding, static structure of .htm files, frame structure + full of hand-typed HTML feel, “View from PC” display with no support for smartphones. ……
What a site made with IBM Home Page Builder, miraculously still active and updated! Miraculously, the site was created with IBM Home Page Builder and is still being updated.
The site was created with IBM Home Page Builder, but miraculously, it is still being updated today.
More substance than appearance, solid quality than superfluous gimmicks.
The appearance of the site also conveys the philosophy that “if something doesn’t need to be changed, it doesn’t need to be changed.
There is no flashy advertising or social network promotion. But those who know choose Daikei.
This may be the true meaning of the words “trust and achievement.