Go Back  R/C Tech Forums > General Forums > Electric On-Road
RC12L3O That likes to spin around to the left under full throttle >

RC12L3O That likes to spin around to the left under full throttle

Like Tree3Likes
  • 1 Post By fermanracer
  • 2 Post By rccartips

RC12L3O That likes to spin around to the left under full throttle

Reply

Old 01-19-2019, 09:15 AM
  #1  
Tech Rookie
Thread Starter
 
Join Date: Apr 2017
Posts: 10
Default RC12L3O That likes to spin around to the left under full throttle

Sorry if this is the wrong section but my problem is I have a RC12L3O Pan car that likes to spin around when I full throttle from any speed. I have foams on the front an rear, 30mm on the front and 50mm on the rear not sure on the shore the rear are bsr racing purple stripe and the front are yellow strip, hobby wing esc 2s or 3s Lipo, engine is a 17.5 t I believe not sure but itís a Novak racing engine canít find the exact engine anywhere. Think itís a 540. Gearing is 38 teeth pinion, 93 teeth spur. Alignment is good checked everything, likes to spin around to the left every time I full throttle at any speed. I can fill throttle from dead stop it takes a second to wind up then it punches it then it does donuts. Thanks for any input. Also driving on asphalt
Mr.Darkness is offline  
Reply With Quote
Old 01-19-2019, 09:43 AM
  #2  
Tech Elite
iTrader: (36)
 
Join Date: Jan 2010
Posts: 2,288
Trader Rating: 36 (100%+)
Default

rebuild your diff and make sure its smooth, check your bearings escpecially in the rear axle
hobbyten likes this.
fermanracer is offline  
Reply With Quote
Old 01-19-2019, 09:48 AM
  #3  
Tech Rookie
Thread Starter
 
Join Date: Apr 2017
Posts: 10
Default

Originally Posted by fermanracer View Post
rebuild your diff and make sure its smooth, check your bearings escpecially in the rear axle
bearings on right side look good an are their suppose to be balls in the holes in the spur gear wasnít sure so I jus made sure everything was like it was before I disassembled it, havenít checked beatings on left rear tire
Mr.Darkness is offline  
Reply With Quote
Old 01-19-2019, 10:16 AM
  #4  
Tech Elite
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 4,576
Default

Sounds like the car is squatting asymmetrically when it accelerates hard. If there were bad bearings I would expect it to pull to one side constantly.

Put the chassis on a table so you can look at it edge-on, then compress the suspension all the way and release. Then lift the front of the chassis with the tip of a pen (or a really small hex driver) positioned along the centerline. If the right-front wheel lifts up first, add preload to the left-rear shock, and vice-versa. Then flip the car around and do the same test on the rear. If the right-rear wheel lifts up first, add preload to the left-front shock, and vice-versa. Do this a couple times until both axles lift off the ground symmetrically. This may not entirely solve the problem, but it should help significantly.

Last edited by fyrstormer; 01-19-2019 at 12:49 PM.
fyrstormer is offline  
Reply With Quote
Old 01-19-2019, 12:58 PM
  #5  
Tech Rookie
Thread Starter
 
Join Date: Apr 2017
Posts: 10
Default

Tried that got everything even the right tire came up first when lifting and the left or right wheel did the same thing, had to add like 8 oz weights to get it even
Mr.Darkness is offline  
Reply With Quote
Old 01-19-2019, 07:18 PM
  #6  
Tech Elite
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 4,576
Default

Wow, is there really a half a pound of weight-imbalance on your chassis? That would certainly cause uneven traction by itself. Can you relocate the electronics from one side to the other to compensate, rather than adding dead weight?
fyrstormer is offline  
Reply With Quote
Old 01-19-2019, 07:50 PM
  #7  
Tech Regular
iTrader: (8)
 
ScottE1776's Avatar
 
Join Date: Jul 2013
Location: Mesa, AZ
Posts: 263
Trader Rating: 8 (100%+)
Default

I would recommend rebuilding the diff using the On Point video on youtube. It sounds as though you've not built one before since you asked about balls in the spur gear. I would also recommend the On Point video on chassis tweak.
ScottE1776 is offline  
Reply With Quote
Old 01-19-2019, 09:16 PM
  #8  
Tech Elite
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 4,576
Default

+1. I missed what he said about the ball diff. If it's not built right it will act really strange. And chassis tweak does sound plausible if he needs that much ballast to get his chassis balanced.
fyrstormer is offline  
Reply With Quote
Old 01-20-2019, 02:31 AM
  #9  
Tech Elite
iTrader: (3)
 
Join Date: Jun 2003
Posts: 4,292
Trader Rating: 3 (100%+)
Default

It is a chassis designed to make left turns around an oval track
RoyU and Sir 51D3WAYS like this.
rccartips is offline  
Reply With Quote
Old 01-20-2019, 03:49 PM
  #10  
Tech Adept
 
Join Date: Jan 2009
Location: colorado
Posts: 237
Default

Itís a lto, so it needs good traction to accelerate in a straight line. If traction is poor it wonít go straight due to the huge % of left side weight. Also if you lift in the center the right rear should be 1/16 in the air before the left rear leaves the ground. Itís called wedge and helps the car work on the left turns. It should not be equal left to right.

We now run, 70-73% left side weight. If you turn right hard it may just roll over.
slotracer577 is offline  
Reply With Quote
Old 01-20-2019, 07:57 PM
  #11  
Tech Elite
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 4,576
Default

Ah, I didn't realize the OP's car was specifically designed to turn left. Yeah, that does make a rather obvious difference in its configuration, not to mention it begs the question of why the OP bought it if he wasn't intending to drive it in the specific way it was designed for.
fyrstormer is offline  
Reply With Quote

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


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service