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General principles race engine
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Is a lighter flywheel right for your classic?

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Is a lighter flywheel right for your classic?

To keep the engine running smoothly, spend to get all the moving parts balanced...flywheel, crank, pistons, rods, drive shaft and rear end gears.

By Tom Suddard
Nov 16, 2025

While completing an overdrive transmission conversion on our 1973 Triumph Spitfire–look for the full story in a future issue–we took the opportunity to make an upgrade, one you’ll never spot on the showfield.

While the transmission was out, we traded the stock steel flywheel for a lightweight aluminum piece from Fidanza Performance. The result? Eight pounds of weight shed. We cut the flywheel’s mass nearly in half.

Notice the clutch friction material in the center area...which is lighter than steel.



Lightweight flywheels are commonly found on race tracks, so why did we install one in our street car? Because this Spitfire is meant for spirited drives on back roads, not long slogs in rush-hour traffic. The stock, heavy flywheel was putting a serious damper on the little four-cylinder’s lively nature.

We paired Fidanza’s aluminum flywheel–figure about $430 for the one we installed–with a stock replacement clutch. It’s a remove-and-replace operation that doesn’t require any fabrication or fiddling. Leaving from a stop now requires a little extra throttle, but we haven’t noticed any major decrease in drivability.



But the payoff: a huge increase in the engine’s playfulness when running through the gears. Now, finally, the drivetrain feels worthy of a sports car.