Gearing a 17.5T BL

[joel45acp]

Hey gents, I know this is a loaded question, but what are you guys running on your 17.5T BL for gearing? I currently have an EZRun 17.5T 2400KV motor and a HB35A ESC running a Gens Ace 4K 30C battery. The track I run on is relatively large and mainly for 1/8 scale stuff. No one at the track runs a 17.5T and I'm not sure where to start etc. 25/80, 26/81??? This will be in a RC10 with Stealth 2.25 tranny and 2.2 tires. Thanks gents and hope you have a great weekend.

[Charlie don't surf]

17.5's and 13.5's are "gear by temp" motors, keep it under 140 for long life, under 160 for best performance. I would bet on a large track with a free drivetrain you would be in the 75/30 range

[joel45acp]

Thanks for the input Reggie. This gives me a good starting point.

[Norman]

75/28 according to the novagear app.

its worked for me great so far.

[Charlie don't surf]

75/28 according to the novagear app.

its worked for me great so far.

I wasn't off by much also the hotter motors like the D3 take more gear

[joel45acp]

I just realized the motor is not a 2400KV, but a 1900KV. Would the gearing you gents suggested still work? The motor is a EZRun 17.5T.

[Charlie don't surf]

Yup, still a temp thing-

[JK Racing]

I was normally gearing 32/69 or 33/72 with my stealth tranny. Motor always came off in the 120 range, little warmer during the summer months. Open flowing high bite track. Novak GTB speed, Losi Xcelrion 17.5 motor.

[joel45acp]

JK Racing, silly question for you, but how fast was your car with that setup in mph? I'm just curious. I have a EZRun 17.5T 1900KV with a Hobbywing 35A ESC and Gens Ace 2s 4000mah battery. I ran the car with a 80/26 and it tops off at 19mph. with the gearing you mentioned, how much faster do you think it would run? Mph is not important, again, just curious. Thanks for your insight.

[Charlie don't surf]

JK Racing, silly question for you, but how fast was your car with that setup in mph? I'm just curious. I have a EZRun 17.5T 1900KV with a Hobbywing 35A ESC and Gens Ace 2s 4000mah battery. I ran the car with a 80/26 and it tops off at 19mph. with the gearing you mentioned, how much faster do you think it would run? Mph is not important, again, just curious. Thanks for your insight.

That's pretty slow, you are way undergeared- ( unless the temps are reading high ) an average non boosted 17.5 should hit 25-30. Boosted can be 40+

[JK Racing]

I have no idea on the MPH, but I can tell you, I was as fast as any modern car on the track that day. I was also able to clear a decent sized triple that most non-boosted cars could not. It was so obvious that my cars were taken to tech after each heat and main, to ensure I wasn't cheating in my "antiques". To add insult to injury , I used my traxxas buggy (TRX3) in one of the heats to take 3rd on the grid for the A main (pretty large race, there were around 30 non-boost stock buggies that day). I ran the gold pan in the main, it felt better as the track changed throughout the day.

Like already mentioned, just run for a few minutes, check temps, and adjust gearing from there. Remember, if you are running a large track, gear for the obstacles, not the straight away. Its better to clear those doubles/triples than be a touch faster on the straight. In the end, the fastest lap time wins, not the fastest car.

[joel45acp]

Charlie, the motor and esc are barely getting warm to the touch after a few minutes. I'm stumped on this one too. I thought I'd be much faster than is. I'm running the motor/esc/batt/gears combo on both my RC10 and B2 and both are running about the same, 19-20mph with esc set at max. timing 26.25. I tried no timing and got about 14mph. I tried the gear combos you gents suggested (75/28, 75/30) and ended up with about 15mph. Batts. are good and fully charged. I check them with voltmeter. My Tacon 3500kv motor is a totally different story. It is a beast! Not sure where to go from here.

[joel45acp]

Charlie, if I'm undergeared, what gearing do you recommend? Any insight is welcome. My cars don't have enough push to clear doubles.

[Charlie don't surf]

Smaller spur and or larger pinions- keep going as close to 1/1 as you can until you get hot. What gear ratio are you at now?

[joel45acp]

not sure on gear ratio, but I'll check. thanks for the insight. I'm bound to make this work or I'll just shoot the darn thing...........motor that is.