looking at pinions
 

the BL conversion is coming alogn just curious about what tooth count i need i'm going to be running a medusa 36-80 2200kv hobbywing 150a and 2 5000mah 2s 7.4 lipos want to go 40 to 45 mph nothing to fast aour track is small and technical anyway thanks in advance i thought i'd try a 12 or 13 tooth pinion running 46 tooth spur

What vehicle?

I would go about 14T to start if its a standard truggy or buggy. Put ya close to 40mph, perfect for small track.

TRUGGY

Differential Ratio: 4.3
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 14
Total Voltage: 14.8
Motor KV: 2200
Tire Diameter (inches): 5.65
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0.006
Spur/Pinion Ratio: 3.29 : 1
Total Ratio: 14.12857 : 1
Tire Circumference (inches): 17.75 inches (450.85 mm)
Total Motor Speed: 32560 RPM
Vehicle Speed: 38.74 mph (62.22 km/h)

BUGGY

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 14
Total Voltage: 14.8
Motor KV: 2200
Tire Diameter (inches): 4.33
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0.006
Spur/Pinion Ratio: 3.29 : 1
Total Ratio: 10.86813 : 1
Tire Circumference (inches): 13.6 inches (345.52 mm)
Total Motor Speed: 32560 RPM
Vehicle Speed: 38.59 mph (61.99 km/h)

I agree....14-15 is a great place to start!