[thzero]

As I said, a pinion with a higher tooth count will lower the gear ratio, which will increase the speed of the vehicle.

Savage Flux out of the box runs a 44/20 spur/pinion which is a 2.2 ratio as compared to your proposed 52/13 which is a 4.0 ratio. So yes, 25mph is probably correct. Rough equivalent of that is a 52/25. However, the Flux is running a 2200kv motor as compared to the 1580kV you are trying to use so you need to lower your gear ratio more, which will be hard to do with a 52t spur due to lack of bigger pinions, and/or use more than 4 cells. You can also toss in the high-speed idler for the tranny which will lower the gear ratio too.

You are going to need at least 6S, maybe more, to get that type of speed with the 1717. I would shoot for 40-45mph to start with.

You would need to give some specifics in order to help further, i.e.
Battery configuration
Tire type
Gear ratio of the KD direct drive
Savage nitro or bulletproof diffs (assuming nitro)