Losi Speed-T Ball Diff Conversion / Aluminum Diff Gears – A solution? We think so!
Posted on July 30, 2009, under Hobbies, Radio Controlled.
Hello again!
This is part 2 of finding a solution to the Losi Speed-T horribly made gear differential.
If you aren’t familiar with my previous post I outlined a common problem with the Losi Speed-T locker differential in the transmissions where the main diff gear strips or eats the center spokes of the gear due to high-end torque that the brushless motor produces.
None the less… for a solution… possibly?
Last night was the first night running the brand new Losi Speed-T for a full battery discharge and the thing is blazing now.
The Losi Speed-T is basically an XXX-T tranny except with a gear diff / locker pads. You have the option to purchase the Carbide Differential Balls and the Diff Grease to make it a ball differential.
After much research we realized that the ball differential would most likely still melt/destroy the diff gear just due to the nature of the vehicle and it’s brushless power. So we decided to purchase a Robison Racing Hardened Aluminum Diff Gear and Idler Gear to replace the existing plastic gears inside the gear box. Let me say, plastic gears DO NOT belong in a brushless motor powered gear box. PERIOD. With a combination of the ball differential conversion and the metal gears we think we finally have a pretty solid Speed-T transmission. Due to the vehicles suspension it’s definitely runs different than say the “Rustler VXL” which does uncontrollable wheelies constantly. The Speed-T still hugs the ground and is definitely street ready even with a ball diff.
The one thing that is still pending in our head is why doesn’t 1 wheel spin the opposite as the other wheel since it’s a ball diff? Possibly gearing differences? Maybe we’re doing something wrong? The car is running but we’re not sure if it’s running the way it should in a ball diff conversion.
Here are the aluminum tranny gears we upgraded to: (Tower Hobbies Pricing)
LXXGM3 Robinson Racing Hard Steel Idler Gear XXX/SPD T 1 $12.99 (Purchase)
LXXGM1 Robinson Racing Hard Aluminum Diff Gear XXXT 1 $16.29 (Purchase)
 Robinson Racing Idler Gear (RRP9402) |
 Robinson Racing Diff Gear (RRP9400) |
Here are the carbide balls and diff grease from Losi:
Losi Diff Lube TEAM LOSI – LOSA3065 – $3.31
Losi Carbide Balls 3/32 – LOSA6951 – $10.78
Reference / Pricing / Purchasing:
http://www.losipartshouse.com/servlet/the-21175/LOSA3065-Losi-Diff-Lube/Detail
 Losi Carbide Balls 3/32 (LOSA6951) |
 Losi Diff Lube (LOSA 3065) |
We’ll keep you posted on the progress of things to see if we find out more about certain tweaks we can make to improve the performance of the vehicle and it’s stamina! Any comments are always welcomed!
-jfr
8 Replies to "Losi Speed-T Ball Diff Conversion / Aluminum Diff Gears – A solution? We think so!"
Andrew on December 6, 2009
Just INSTALLED the DIFF
SPEED T works GREAT!
I also wrote LOSI a letter complaining agout their cheap design on diff parts
You can also purchase RRP9901 for a DIRECT REPLACEMENT spool design at Hobbytown for $17.99
They stock EVERYTHING at my Concord Ca store.
Joshua on December 6, 2009
Yep, this works great! You’re welcome for the post.
Hope this helps lots of people! We went through several replacement gears until we finally got it. Want to save people some time!
jesse on December 7, 2009
I just ran int the same problem too, I called up horrizon hobby (losi) hand they are sending me a new gear for free(a friken backup)
jesse on December 11, 2009
So hey guys what other problems have you guys ran into with the speed-t seems like every time I get one problem fixed I run into another one any advice?
Chip on December 26, 2009
I just had this same problem but after reading this, I’m not entirely clear on how you rebuilt the diff locking gear. Were you able to slip it right in with the ball bearings? i went to my local shop and they were looking at me like “you don’t know?” any they didn’t help me at all. I was ticked off and left. Nothing like smoking a $300 car with a $100 battery in less than ten minutes! Any help on specifics (which parts to keep/toss) would be greatly appreciated. My plastic diff locking gear completely stripped/melted off and spins around the outside of the diff. So engine is spinning but wheels are not. So i’m planning on buying the 2 above gears but not sure how to do ball bearings.
Thank you.
Joshua on December 27, 2009
Yep all you need to purchase are the 2 new metal gears and the diff balls and diff lube for the diff balls. You’re converting it from a lock diff to a full metal ball diff. Kind of like the Rustler VXL. The correct diff gears have holes for the diff balls to fit in.
Andrew on December 27, 2009
I would also recommend installing ALUMINUMSteering servo savers, Front ALUMINUM A-Arms and RPM wide front bumper from XXX-T parts.
Eventually,just a knick on the front at high speed will break those stock arms and steering pieces!
I switched out the Losi Excelorin 4800KV for Castle Creations Mamba Max PRO 5700KV.So far …so good! 70MPH easy!
Andrew on December 5, 2009
Thanks for the updated info!
I figured out the EXACT same conclusions when running my New Speed T for only FIVE MINUTES last night!
I have ordered the parts and am awaiting the day that Losi WAKES UP and realizes that thse parts need to be made of METAL!!!