GFB lightweight pulley kits are made from aircraft-grade 6061-T6 aluminium and offer faster acceleration through significant weight reduction on the crankshaft. The effect is similar to a lighter flywheel, and the car feels more lively and willing to rev.
Most of our kits are underdriven, which means the accessories are driven slightly slower to reduce parasitic losses. It should be noted that our underdrive pulley kits do NOT adversely affect the operation of the accessories. If they did, we would not sell them!