Can You Fit A New Steering Wheel And Quick Release Without A Boss Kit?
Steering wheel fitting guide
Short answer: on a road car, no. An aftermarket steering wheel or quick release will not bolt straight onto a car's steering column. You need a boss kit made for the car in between, and the wheel and quick release fit onto that.
The good news is that the boss kit does not tie you to one brand. A MOMO boss kit will take an OMP or Sparco wheel, because they share the same bolt pattern. Here is how the pieces fit together, and the one exception to the rule.
- A steering wheel or quick release needs a boss kit made for the car
- The boss kit matches the column on one side and the wheel pattern on the other
- MOMO, Sparco and OMP wheels use a 6 bolt, 70mm pattern
- Nardi and Personal wheels use a 6 bolt, 74mm pattern
- A quick release fits between the boss kit and the wheel
- Weld-on quick release hubs are for dedicated competition cars
What is on this page
Why a boss kit is needed
Every car’s steering column ends in a splined shaft, and the spline count, taper and fixing are different from one car to the next. The standard wheel is made for that shaft. An aftermarket wheel is not: it has a flat centre drilled for six bolts.
The boss kit, also called a hub adapter, bridges the two. One end is cut to match your car’s column, and the other end is drilled for the wheel. It also sets how far the wheel sits from the dash, which affects your reach to the stalks and the clearance to your knees.
A boss kit comes with the screws to fit the wheel to the hub, and it carries the horn contact through so a wheel with a horn push still works. You reuse the column nut from the standard wheel.
If the car has a driver airbag, that is lost when the standard wheel comes off. Disconnect the battery before you start, have the airbag dealt with properly, and tell your insurer the car has been modified.
Mixing brands: MOMO, OMP and Sparco
The part people ask us about most is whether a MOMO boss kit will take an OMP or Sparco wheel. It will. MOMO, Sparco and OMP wheels all use a six bolt pattern on a 70mm pitch circle, and a MOMO boss kit is drilled to match.
Nardi and Personal wheels use a 74mm pattern. The B-G boss kits we list are drilled for both 70mm and 74mm, so they take either. Garreth’s advice is to check the back of your wheel before you order the hub, especially if it is an older wheel.
| Wheel brand | Bolt pattern |
|---|---|
| MOMO, Sparco, OMP, Sabelt | 6 x 70mm |
| Nardi, Personal | 6 x 74mm |
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Where the quick release goes
A bolt-on quick release does not replace the boss kit. It bolts onto the face of the boss kit, and the wheel bolts onto the quick release. Pull the release and the wheel comes away, which makes getting in and out easier in a car with a bucket seat and a cage, and means the wheel can come with you.
A quick release adds depth, so the wheel sits closer to you than on the hub alone. Take that into account when you choose the wheel’s dish. Our guide to steering wheel dish explains how dish changes your driving position.
The exception: weld-on hubs
The only way round a boss kit is a weld-on quick release hub, such as the Sabelt RFMO0002. The male half is welded permanently to the steering column in place of the spline, and the wheel side locks onto it.
It is a permanent change to the column, and it is used in dedicated competition cars such as rally and touring cars. For anything that still sees road use, a bolt-on boss kit is the way to go. Our hub guides list the boss kits by make, for example the B-G and MOMO Ford hub guide.
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Can I fit an aftermarket steering wheel without a boss kit?
Not on a normal bolt-on install. The wheel needs a boss kit made for your car to fit the column.
Will a MOMO boss kit fit an OMP or Sparco wheel?
Yes. MOMO, OMP and Sparco all use a 6 bolt, 70mm pattern.
Does a quick release replace the boss kit?
No. A bolt-on quick release fits onto the boss kit, and the wheel fits onto the quick release.
What is a weld-on quick release?
A hub welded permanently to the column, used in dedicated competition cars in place of a boss kit.
Will I lose my airbag?
Yes. Taking off the standard wheel removes the driver airbag on any car that has one.
Get the boss kit right for the car, and you can choose from any 70mm pattern wheel.
Give us the make, model and year and we will tell you which boss kit fits and which wheels go with it.
