Quick opening and closing rates require premium-quality springs to “keep up,” warding off valve float for maximum power.
Despite this, many racers consider the increased cost of roller valvetrains a small price to pay for the increased performance they provide.
Although the roller tappets are intended to reduce friction, the rollers themselves place higher loads on the lobes since the actual contact patch between the two is smaller than that of a flat tappet setup.
This load is then intensified by the fast opening rates, higher valvespring pressures, and extra tappet weight.
Later, hydraulic versions of the roller became available, first from the OE manufacturers and then from the aftermarket.
Roller cams must be ground on specific blanks, usually made from hardened or billet steel rather than the cast iron typically used with flat-tappet cams.