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Old 11-25-2014, 10:41 AM   #1
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So I am finally making the change from a mostly scale builder to attempted racer. After reading some threads on this site, I decided to try USVTA.
Outfitted a Tamiya 418 with a spec VTA set-up (wheels/tires/J71 body/5000mah lipo) and put 2 mill in the rear diff and 40 in the front and rear shocks. The carpet track I plan to race on is medium grip.

Practice #1 - Car ran very well after the tires scrubbed in a little and was neutral in the corners. Using a 25.5 motor I actually could drive the car just fine and got a fair amount of laps in before I finally tried to go too fast and broke a C-hub. I spoke with a couple regulars at this track and they thought my car was riding too high and that I should try some traction compound next time.

Practice #2 - Adjusted the car's ride height to 5mm per USVTA rules and bought the tracks one legal tire sauce. The track owner said to put sauce on the whole rear tire and just the inside of the fronts. I did this. These were the only two changes I made. The car pushed something horrible, I really struggled in the infield section and it made driving it very difficult for me.

Question - Is this just the rear tires getting so much traction that they are overpowering the fronts? Should add traction sauce to the fronts and only coat a small amount to the rears? Should I add weight to the front of the car? I played with a couple things but nothing really helped. Looking for a few things to try and solve this.
Any help is appreciated.
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Old 11-25-2014, 10:46 AM   #2
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2 million in the rear diff? I think that may be the issue. Drop down to 2K in the rear and try it out.

The 2 million is hurting your turn in and thru tight transitions. Replace the rear oil and give it another shot and report back to us.
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Old 11-25-2014, 10:48 AM   #3
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Quote:
Originally Posted by Mitamiya View Post
So I am finally making the change from a mostly scale builder to attempted racer. After reading some threads on this site, I decided to try USVTA.
Outfitted a Tamiya 418 with a spec VTA set-up (wheels/tires/J71 body/5000mah lipo) and put 2 mill in the rear diff and 40 in the front and rear shocks. The carpet track I plan to race on is medium grip.

Practice #1 - Car ran very well after the tires scrubbed in a little and was neutral in the corners. Using a 25.5 motor I actually could drive the car just fine and got a fair amount of laps in before I finally tried to go too fast and broke a C-hub. I spoke with a couple regulars at this track and they thought my car was riding too high and that I should try some traction compound next time.

Practice #2 - Adjusted the car's ride height to 5mm per USVTA rules and bought the tracks one legal tire sauce. The track owner said to put sauce on the whole rear tire and just the inside of the fronts. I did this. These were the only two changes I made. The car pushed something horrible, I really struggled in the infield section and it made driving it very difficult for me.

Question - Is this just the rear tires getting so much traction that they are overpowering the fronts? Should add traction sauce to the fronts and only coat a small amount to the rears? Should I add weight to the front of the car? I played with a couple things but nothing really helped. Looking for a few things to try and solve this.
Any help is appreciated.
i think the 2 mill i the rear diff isnt helping, that is what i would use in a front diff. 30-40 wt would work better in the rear with a spool or slipper in the front.
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Old 11-25-2014, 10:49 AM   #4
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Dan's got it. Change out that rear diff fluid before trying anything else.
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Old 11-25-2014, 02:51 PM   #5
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With Diffs you want light light in the rear and Thick in the front in My sakura I run 1 mil in the front and 100wt in the rear
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Old 11-26-2014, 12:35 AM   #6
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In my 418 with a 13.5T in blinky, I run anything in between 1000 - 3000 in diff oil.

Guess the kit dif oil is 900.
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Old 11-26-2014, 03:02 AM   #7
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Along with changing your diff fluid, clean your tires between runs with compound or lighter fluid. These tires will pick up debris and make it impossible to get traction. I would also agree that you should sauce more of the front tires, but continue to sauce the entire rear.
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