Thread Tools
Old Mar 09, 2013, 11:52 AM
pfindeis is offline
Find More Posts by pfindeis
Registered User
Question

sf501 nitro to brushless gear ratio ?


Going to convert a sf501 nitro to brushless.
Have a thunder power 13.5 sensored motor and a lrp sphere tc esc.
Probably go with 48 pitch gears.
What would be a starting gear ratio / size 48p pinion and spur?

Thanks
Last edited by pfindeis; Mar 09, 2013 at 05:46 PM.
Sign up now
to remove ads between posts
Old Mar 09, 2013, 02:58 PM
z_dad is offline
Find More Posts by z_dad
Kungsangen, Stockholm, Sweden
z_dad's Avatar
The original primary gearing (motor gear to first) for the SB5 is 21/87, it makes 4,1429 motor revolutions per layshaft revolution.
As long as you have secondary gearing (front chain pulley to rear) fixed to 2,5 (20/50, original sb5) you will end up whith a final ratio at 10,537. This seems to a be very good start for motors 4500-6000kv.
In clear terms: 87/21x50/20 = 4,1429 x 2,5= 10,357
Put in the relevant nubers for your bike to reach the final gearing.
I wouldn't go under 9 total, unless you know your electrics well. Higher than 10,5 makes for less top speed unless you have a very high kv rating.
Hope this helps for starters.
Old Mar 09, 2013, 03:23 PM
pfindeis is offline
Find More Posts by pfindeis
Registered User
Quote:
Originally Posted by z_dad View Post
The original primary gearing (motor gear to first) for the SB5 is 21/87, it makes 4,1429 motor revolutions per layshaft revolution.
As long as you have secondary gearing (front chain pulley to rear) fixed to 2,5 (20/50, original sb5) you will end up whith a final ratio at 10,537. This seems to a be very good start for motors 4500-6000kv.
In clear terms: 87/21x50/20 = 4,1429 x 2,5= 10,357
Put in the relevant nubers for your bike to reach the final gearing.
I wouldn't go under 9 total, unless you know your electrics well. Higher than 10,5 makes for less top speed unless you have a very high kv rating.
Hope this helps for starters.
Yeah i don't understand that math. Sure is a lot easier with online car gearing charts.
Maybe i should reword my post to what size 48p pinion and spur
Thanks though
Old Mar 09, 2013, 06:44 PM
dragbikebam is offline
Find More Posts by dragbikebam
Registered User
dragbikebam's Avatar
you can run the HPI or X-ray 48p spur from 84 to 96. I prefer 90 to 93 with a 22 to 26 pinion. With a 13.5 I would go with a 90/26 to start then go to a 28 pinion if you want more top end..
Old Mar 09, 2013, 06:53 PM
pfindeis is offline
Find More Posts by pfindeis
Registered User
Hey thanks alot


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Gear ratio recomendations needed erikdravn Off-road Cars 1 Feb 28, 2013 09:20 PM
Sold F5D - NEU Motor 1512-1.5D/6.7/1 Gear Ratio Jaguar22 Aircraft - Electric - Power Systems (FS/W) 2 Jan 18, 2013 08:20 PM
Discussion Anyone know the gear ratio on Parkzone P-51 UM? JT2 Electric Plane Talk 1 Jan 10, 2013 12:59 AM
Discussion Anyone here with a brushless converted Nitro NF SF501 ? saucisse Motorcycles 2 Feb 11, 2009 11:03 PM
Discussion Gear ratio calculation on sf501? Junglemaxx Motorcycles 4 Mar 04, 2007 11:27 AM