R/C Tech Forums

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

Thread Tools Search this Thread
Old 06-26-2004, 07:12 PM   #1
Tech Elite
macnkitty2002's Avatar
Join Date: Jun 2004
Location: Montgomery, AL
Posts: 4,920
Trader Rating: 7 (100%+)
Unhappy hpi sprint gearing help

I've got an HPI Sprint, which is not the best electric to race with in the first place. I stuck a 17 turn motor in it and put a 64 pitch 122 tooth spur and a 31 tooth pinion. I got plenty of run time and a killer take-off, but no top speed! How should I gear it to reduce the take-off and increase the top speed? How can I keep up with the big guys without getting another motor?

Thanks for the help
Mac Scott
macnkitty2002 is offline   Reply With Quote
Old 06-27-2004, 02:41 AM   #2
R/C Tech Founder
R/C Tech Charter Subscriber
Join Date: Aug 2001
Location: Del Mar, CA, USA
Posts: 7,063

If the faster people are running lower wind motors (10, 11, 12 turn) it will honestly be tough for you to keep up with them using a 17.

Otherwise, you can always try gearing up a couple of teeth on the pinion, but don't overgear it. Try not to go below an 8.0-8.5 final drive ratio. You can calculate the ratio like this:

(teeth in spur / teeth in pinion) x internal drive ratio

Not sure what the internal ratio is on an HPI Sprint, you may have to check www.hpiracing.com for that information.

If you need a cheap, lower-wind motor to keep up, you might try one of Trinity's machine-wound Speed Gems motors. They are in the $35-or-so range and should get you a bit closer on top speed.
Visit my store: www.ampdraw.com
futureal is offline   Reply With Quote

Similar Threads
Thread Thread Starter Forum Replies Last Post
1/10 sprint car radsnappy R/C Items: Wanted to Buy 1 06-14-2008 10:55 AM
Hpi Sprint 1 BayArea101 Electric On-Road 2 08-01-2007 10:00 AM
Need Help!! Hpi Sprint SArehart Electric On-Road 3 03-07-2007 12:02 PM
HPI sprint merc-blue Electric On-Road 0 01-09-2005 04:00 PM
HPI sprint merc-blue Electric On-Road 2 01-07-2005 04:40 PM

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 11:58 PM.

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