Tuesday, December 01, 2009

That's not a wheel. THAT'S a wheel.

When I bought Emma, my 1995 Miata, she came with numerous performance parts. Since my plan was---and is---to make her my dedicated track/autocross/time-trial* car, this collection of parts was the primary reason I bought this particular '94-'95 Mx-5**.

One of these parts was a very nice Momo Team steering wheel. Unfortunately, at 300 mm in diameter, this wheel is laughably small. When Alison drove the car, she said she felt like she was driving a Cozy Coupe, but with enormously higher steering effort.*** the previous owner was a taller guy, and I think he needed the extra clearance for his knees and thighs, especially when sliding into the race buckets. Aside from the required steering force and the sheer silliness, there was another drawback to this size wheel. I was unable to see my oil-pressure gauge (sic) or the tops of my tachometer and speedometer. Observe:

I needed a new wheel, clearly. But what size? After poking around on SpecMiata.com, Miata.net, and the Chesapeake Area Roadsters forum, I settled on 350 mm and ordered a Momo Mod 78 in that size from an online retailer for a price well below MSRP. As you can see, gauge visibility was dramatically improved:

Steering effort was reduced, as well. It's now a little heavy at anything under about 5 mph, but at any faster speed, it's just about perfect. As a result, the car feels much lighter and more nimble, even though the vehicle itself is unchanged. This wheel comes with a suede cover, which I thought would give me extra grip. I was correct about that, but suede has another benefit: it just feels very nice.

The Mod 78 has an "anatomic" grip, which appears to mean that the rim is deeper than it is wide. It's fine when my hands are at 9 and 3 o'clock, which is where they spend 90% of their time, but at other positions, it's simply uncomfortable. If I had to make the purchase over again, I might go with the Mod 69, which is the non-anatomic version of the wheel.

Here's one more photo for you. It's a pic of the stock wheel (about 370 mm), the new Momo Mod 78, and the old Momo Team. The difference in diameter is readily apparent, but what you can't see is the weight difference. The two aftermarket parts have similar mass (about 7.5 pounds), but the stock wheel is probably around 15 pounds, due mostly to the airbag.

* Someday.
** I was looking specifically for a 1994 or 1995 Miata, for reasons I'll explain later.
*** Emma was built with power steering, but the steering rack has been depowered. This modification results in much more precise steering feel, but at the cost of higher required force, especially since the power rack has a quicker ratio than the manual rack that was available on the NA Miatas.


  1. Question: Is the car still street-legal with one of its significant safety features removed?

  2. Yes. It passed the Maryland safety inspection with the smaller Momo in place. Apparently, since not all cars came with airbags, a car isn't required to have one to pass.