Clutch Inertia

ChipsWithDips

Yep the effects of rotational inertia (clutch and flywheel and pulleys and all that really) are more significant in lower gears. I've posted about this before in relation to dyno readings in different gears: Dyno pull in 4th any equation to tell how much it would've made in the correct gear?

Keep in mind that rotational inertia isn't just about the mass of the object, but also how far along the radius that mass is distributed. Twin and multi-plate clutches are typically able to be made in a smaller diameter than a single plate for the same or more clamping force.

Take a look at the thin solid disk example here: List of moments of inertia - Wikipedia, the free encyclopedia

The equation given for its moment of inertia is this:


So the inertia is directly proportional to the mass, but also directly proportional to the square of the radius. This means that reducing the radius will have more effect than reducing the mass by the same factor.

Less inertia in your clutch is equivalent to a slightly lighter flywheel for the parts of the clutch that rotate with the flywheel(pressure plate and diaphragm spring).

And for the friction disks that are connected to your transmission input shaft, less inertia on them will mean less load on your synchros during fast shifts.

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