R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Thread Tools Search this Thread
Old 06-05-2013, 10:48 AM   #1
Tech Apprentice
Join Date: Apr 2013
Posts: 51
Trader Rating: 3 (100%+)
Default HPI sprint 2 with 9T motor

Hey guys I am new to the hobby and I recently installed a 9T brushless motor in the car.

Gearing is the stock 23Pinion and 90Spur.

Issue I have is the car is not making the motor work to its potential. It's slow to take off and takes long to get up there.

Wondering what gearing I should run. I am new and still somewhat confused about the pinion and spur ratios but would like to learn.

Also what's the difference between 48 pitch and 64pitch gears??

thank you
Vroomin is offline   Reply With Quote
Old 06-07-2013, 08:17 AM   #2
Tech Apprentice
Join Date: Apr 2013
Posts: 51
Trader Rating: 3 (100%+)

Vroomin is offline   Reply With Quote
Old 06-07-2013, 08:49 AM   #3
Tech Master
locked's Avatar
Join Date: Mar 2010
Location: Toronto
Posts: 1,758
Trader Rating: 1 (100%+)

With that gear ratio, 90/23 x 2.13= 8.33 FDR (2.13 is a sprint2's internal ratio), it shouldn't really be slow accelerating. Maybe there is some resistance in the drivetrain. Bad bearing, belts rubbing on the motor or the battery, etc. If you disconnect the motor(loosen the screws and drop the motor down so the pinion isn't touching the spur), does everything spin nice and freely? Does the motor get really hot, quickly.

You can try a smaller pinion. It should help improve acceleration, but I suspect there is some other issue going on here.

48p gears have larger teeth than 64p. 48p won't strip as easy as 64p, but doesn't allow for as fine adjustments to the gear ratio.
locked is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

All times are GMT -7. It is currently 01:58 AM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net