1518 4s?

[simplechamp]

I just installed a 1518 in my F8T and have it geared 16/52 on 4S for about 40mph (I should note the F8T has 43/13 ratio in the front and rear, not very common in truggies).

The max RPM achieved with the 1518 on 4S is a bit low of the 30-35k sweet spot, but I think it is still OK. The extra torque provided by the 1518 over the 1515 should allow you to go up a few teeth on the pinion and gear for the same speed as with the 1515.