When I decided to replace my stock Miata steering wheel with a smaller sport aftermarket wheel, I opted to use a Momo steering wheel hub for Miata for the installation. Since Momo is the only company that I’m aware of that makes a crushable hub I was adamant about it.
The steering wheel hub, otherwise know as the boss hub or steering wheel boss, is a necessary part for installation of an aftermarket steering wheel in a car previously equipped with a stock airbag type steering wheel. A crushable or collapsible steering wheel hub will crush under impact to absorb a bit of the force if you happen to smack it with your body during an accident. Since I’m removing the stock airbag, I figured I would add this little bit of security. Mind you, I don’t know how much it would really help, but on paper, the concept of a collapsible hub makes sense.
However, upon searching the internet for information on the MOMO hub adapter I realized I couldn’t find a decent picture or set of dimensions for the MOMO steering wheel hub specifically for Miata. I decided then to snap a bunch of good photos and include dimensions for those of you that might be interested in using one for your Miata. The photos are beautiful, aren’t they?
One thing I discovered is that at 2.25 inches / 57mm, the MOMO Miata steering wheel hub is actually very slim compared to other popular hubs for Miata such as Works Bell and Daikei hubs. This makes it so that it’s super important to be aware of the height of the hub. Barring really deep dish steering wheels, with most aftermarket steering wheels from MOMO, Nardi, Personal and NRG, if your intention is to use the MOMO hub alone you will end up with the steering wheel too far from you – further than stock. This might be OK for the giants that want to drive Miatas (Miatae, for the really geeky), but for most of us it will actually hinder driving performance.
To set a baseline remember this:
The stock steering wheel in a Miata NA (1990-1997) is exactly 5” / 127mm from the plastic base of the steering column to the outer edge of the stock steering wheel (the top edge, closest to you).
So basically, your goal with the aftermarket wheel is that after stacking the parts together, you would likely want to be near stock position, or a bit closer to you for a more sport-oriented driving position.
Of course, this is just a rule of thumb. The really tall guys with huge long arms might want to push the steering wheel slightly away. Those that are very worried about having removed the airbag might also want the steering wheel even further away.
With the 2.25” / 57mm MOMO hub, to clear the 5” / 127mm mark you would need roughly 3” / 76mm of steering wheel on top. Give or take. That’s a lot considering a Nardi Classic steering wheel is only 1” / 25.4mm deep. Same thing goes for most of the MOMO shallow steering wheels. Then you have the Nardi Deep Corn 350mm which is 3.15” / 80mm, which sounds like it would be spot on with stock position. However, the Nardi steering wheel bolt pattern will not fit the MOMO steering wheel hub pattern, so you would need a spacer / adapter anyway.
For shallow steering wheels, most adapters are still too slim to make up the difference. If you’re expecting to skip a spacer altogether, get a MOMO deep steering wheel then. Something like a MOMO Mod 07 at 2.75” / 70mm or a MOMO Mod 08 at 3.5” / 90mm would do the trick.
See what I’m getting at? Anything shallower than a deep dish steering wheel and you would need a spacer or a quick-release to make up the difference. Plus, not all deep dish steering wheels will be deep enough. My choice of wheel was the Nardi Deep Corn 330mm. That one, at 2” / 53mm still leaves me .75” / 19mm shy of stock height. And my actually goal is 6” / 152mm total – 1” full inch over stock. Meaning my MOMO to Nardi adapter would have to be at least an inch tall to even be within range.
Here’s a photo of how my the MOMO Miata hub looks like with a Nardi Deep Corn 330mm steering wheel stacked on top. Note, the Nardi wheel won’t fit the MOMO hub without an adapter.
The point of all this is to measure. Then measure again. Don’t just buy the MOMO steering wheel boss hub and any steering wheel blindly. Make sure you have a plan as to how tall of a setup you’re going to end up with and whether or not the hole patterns are compatible. Otherwise you’re going to be spending a lot of time and money swapping out parts.
One thing to note about the MOMO Hub for Miata:
You will need to do a lot more modifications of the hub, steering clock spring connection and airbag connection than you would with a Daikei or Works Bell hub. The latter two are basically plug and play. Many Miata guys have done the install successfully though. However, when I did my installation I wasn’t particularly happy with their method of modifying the clock spring connection to to work with the MOMO hub so the installation was rather a pain in the butt and took much longer than I would’ve liked. Additionally, and I haven’t heard anybody mention this yet in any installation write-up I’ve read… You have to grind down the round edge of the plastic steering column cover about 1mm otherwise it will rub against the hub when you steer. This is on our 1995 Miata by the way.
That’s it. The MOMO steering wheel hub for Miata is a great choice for those who would prefer a collapsible boss hub for their aftermarket steering wheel installation. So long as you’re willing to deal with the more complex install and modification process. By the way, we ordered our MOMO hub from our friends at Guerilla Racing. If you don’t see the part available on their website, hit them up by email or phone. They can order up pretty much whatever you need.