Feigao Mix Up....I Think?

I have a Hyper 7 with a 9xl geared 13/46 and according to the speed calc it should do this:

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 13
Total Voltage: 14.8
Motor KV: 1853
Tire Diameter (inches): 4.6
Tire Ballooning (inches): .15
Motor Current Draw: 0
Motor coil Ω: 0.0092
Spur/Pinion Ratio: 3.54 : 1
Total Ratio: 11.70414 : 1
Tire Circumference (inches): 15.39 inches (391 mm)
Total Motor Speed: 27424.4 RPM
Vehicle Speed: 34.16 mph (54.87 km/h)
Effective KV Value: 1853



Now the issue. I clocked this with a gps in the car at 55 MPH!!!!! I believe someone at the factory confused a 6xl with a 9xl. Has anyone had this happen before. Here is the calc with a 6xl:

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 13
Total Voltage: 14.8
Motor KV: 2779
Tire Diameter (inches): 4.6
Tire Ballooning (inches): .15
Motor Current Draw: 0
Motor coil Ω: 0.0041
Spur/Pinion Ratio: 3.54 : 1
Total Ratio: 11.70414 : 1
Tire Circumference (inches): 15.39 inches (391 mm)
Total Motor Speed: 41129.2 RPM
Vehicle Speed: 51.23 mph (82.29 km/h)
Effective KV Value: 2779
KT constant: 0.49 oz-in/A


Do you guys think a 6xl will last on 4s?

[brushlessboy16]

what are temps like?

[zeropointbug]

Yes, I am pretty sure I have a 7XL that is actually a 6XL, because it's way too fast for a 7XL. I did some calcs yes, and compared the proper gearing with my 1512 3D on 7s2p A123 and the "7XL" is much faster, when they SHOULD have the same top speed. I am sure it's ~7mph faster...

It ran BLOODY hot too, 220+F after some runs.

[BL_RV0]

I think it's probably that you don't have enough tire ballooning factoured in. Buggy tires can still balloon .5-1"

[zeropointbug]

Well he does have the wrong value for ballooning, but still, not enough ballooning to go from 35mph theoretical to 55mph real world... do you know what those tires would have to look like?

[scarletboa]

Originally Posted by zeropointbug

Well he does have the wrong value for ballooning, but still, not enough ballooning to go from 35mph theoretical to 55mph real world... do you know what those tires would have to look like?

like my savage tires at 50mph+. they go from stock 5.5in to about 8 or 9 in.

Originally Posted by BL_RV0

I think it's probably that you don't have enough tire ballooning factoured in. Buggy tires can still balloon .5-1"

I would have to have over 1.5" of ballooning to get to 55mph and I can physically see they aren't ballooning anywhere near that much. That would also almost double the size of the original tire. The calc uses the radius so you have to double that to get overall ballooning. Temps are pretty close to 200F.

[BL_RV0]

Yeah, they did send you the wrong motor then. I guess just sell it or try to return it, but I'd imagine feigao's CS sucks...