Requesting help figuring out my final drive / wheel speed problem.

[GTSLOW]

Good Afternoon RCC, I recently built a VS4-10 Phoenix and installed a Toyzuki FMM/2.5 case. The issue I am having is it's SLOW running a 16T Puller 400 on 4S. My concern is that I did not take into account for the portal reduction.

Currently I am running:

56T Spur + 10T pinion = 5.60
Toyzuki 2.5 case = 1.8 to the front tires
30/8 R&P = 3.75
20/28 portal gears = 1.4

5.60 x 1.8 = 10.8 transmission ratio
3.75x1.4 = 5.25 axle ratio
10.8x5.25 = 56.7:1

If I recall correctly my old SCX10ii had a 54.6:1 with a 56/10 setup and it had very nice wheel speed with the same motor and ESC. Am I missing something with my math? It was recommended that I run a 46T spur gear with a 10t pinion.

My goal is to get respectable wheel speed and not roast my motor or BR mini.

I ordered a batch of Kimbrough spur gears 42, 44, 46, and 48. I've also get everything from a 8-16t pinion. Any recommendations on where I should start?

 

[DRED805]

Math looks right to me. The only thing I can see that'd make it slow is if you're running tiny little tires.

According to HH, the 16t puller 400 is roughly a 2200kv motor. Put all that info into this calculator and it's easy to figure out theoretical speeds with different spur/pinion ratios. Off the top of me head, theoretically, that combo you're running shouldn't be slow... so who knows.

https://scriptasylum.com/rc_speed/top_speed.html

 

[HumboldtEF]

I may be alone in this but just recently I adjusted the travel for throttle on a rig for the first time. I guess I've always assumed the ESC calibration was all I needed to get 100% throttle. Anyway on this particular rig I needed the throttle travel set to around 130 to actually get top speed out of the motor. Before I did this I thought the motor was just slow, it seemed like I was only getting 60-70% throttle when I had the throttle fully pulled back. I've also had motors in the past that ran faster in reverse no matter what I did which puzzled me but after adjusting the travel it was back to normal (forward being faster than reverse).

This thread just reminded me I need to go through all of my rigs and check this, I just checked my Capra which needed the travel set to 126 or so for forward and reverse. I'm just holding it at full throttle and listening while I adjust it up and down, You'll hear it as it speeds up or slows down.

 

[GTSLOW]

I may be alone in this but just recently I adjusted the travel for throttle on a rig for the first time. I guess I've always assumed the ESC calibration was all I needed to get 100% throttle. Anyway on this particular rig I needed the throttle travel set to around 130 to actually get top speed out of the motor. Before I did this I thought the motor was just slow, it seemed like I was only getting 60-70% throttle when I had the throttle fully pulled back. I've also had motors in the past that ran faster in reverse no matter what I did which puzzled me but after adjusting the travel it was back to normal (forward being faster than reverse).

This thread just reminded me I need to go through all of my rigs and check this, I just checked my Capra which needed the travel set to 126 or so for forward and reverse. I'm just holding it at full throttle and listening while I adjust it up and down, You'll hear it as it speeds up or slows down.

You know I'm going to do just that! I never did re-calibrate the ESC to my new Futaba 4PLS.

 

[Joshs4x4toyz]

56/10*1.8*3.75*1.4=52.9 Fr
56/10*2.6*3.75*1.4=76.4 Rr

Looks to me like it is going to be little slower than the 10ii setup for sure, plus "dragging" the rear a bit. Hard to say, but you having first hand experience with them would be able to know better. That 16t on 4s should be decent in wheelspeed department. But portals and OD/UD combos can really eat wheel speed in my experience.