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smirk-racing

ball diffs for xv-01?

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I have reached a new place in my enjoyment of RC, in which I no longer wish to shove massively overpowered brushless motors and 6s lipos into tiny 1/10 scale chassis. Nowadays, I am looking for finesse.

So, for my on-road basher, a used XV-01, I've turned the power WAY down, and I'm limiting myself to 3s (and small packs at that). Still, it moves incredibly fast.

I am trying to get a feel for how the chassis responds to changes, and in particular to how diff action affects on-road performance, but tearing into the gearboxes and swapping diff oil is tedious to say the least. I need to be able to make changes more quickly to dial-in the performance for what I'm trying to achieve.

Are there ball diffs that fit into the XV-01? I assume the Tamiya on-road balls diffs would fit... I am willing to give up a bit of the durability and robustness of gear diffs in favor of a bit more easy street-side tuning.

Thanks!

 

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The XV01 uses the TA06 type gear diffs, so the ball diffs you wsnt are either the FF03 or TRF201 type. Both are basically the same and are narrower than the gear diffs so you need the spacers to fit over the outdrives. Pretty sure thry are on one of the 201 or ff03 parts trees. They don't exist as complete units so you have to buy parts. If you want to go cheap and cheerful rcmart are selling off the yeah raving outdrives which is usually the biggest expense

http://www.rcmart.com/yeah-racing-ff03069bu-aluminum-ball-differential-joint-tamiya-ff03-p-32530.html?cPath=595_744_1471

You'll need the thrust washer, diff spring and diff gear and diff balls to complete it. Tamiya items are 54242 for the gear and 49299 for the spring. Any 3/32" diff balls will fit, so buy the spec you want, and some top end ball diff grease. Can't fing the thrust washerpart numbers, but if you download the basic FF03 chassis manual and look at the parts list you will find one. That came with ball diff as standard. 

 

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There's TA06 ball diff kit, 54306, that should fit perfectly into XV's gearcase.

FF03/TRF201 diff is narrower, you'll need some 5+mm of shims for good fit.

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The TA06 rear ball diff is a direct fit into the XV-01, M-07, and M-08. It has aluminum outdrives that require you to use the plastic parts over the end of the axles. I bought two for my XV-01, but I installed one on my M-08. I'm a little worried about the diff being able to take punishing crashes in the rally XV-01. The FF03/TRF201 diff uses hardened steel, so I might try that. Thanks for the tip. The parts number for these is 19804410. The plastic gears used for the TA-06 and FF03 are the same part though.

Edited by Quailane
add part number
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3S is a lot of power for an on-road chassis, even with a fairly mild motor, and an overpowered chassis can be very difficult to tune. You are sort of covering up the chassis tune with God awful amounts of horsepower and tire spin. 

I've found my XV01 to be very responsive to adjustment with a 13.5 and 2S, while my friend's cars that have much more horsepower, especially those with four pole or sensorless, are much harder to set up right, to the point that my lap times are substantially better. Currently, I'm using 60k front, 900 rear diff oils, and I have good brakes, turn in, and exit on rally-type surfaces.

The huge increase in torque with a 3S is probably making the car very hard to drive smoothly, so maybe going with a higher kV two-pole sensored motor on 2S would allow you to tune the chassis more easily, without switching to an inherently weaker and more maintenance intensive differential type. Of course, if you prefer the brutality of a 3S, I'd think that the ball diffs, combined with a properly adjusted slipper, would allow you to dial the chassis in a bit quicker. 

 

 

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This is a good point. I might need to step down the motor and the battery. Right now I have the torque control (which limits current) turned down to 1.4 out of 10, and that just about eliminates wheelspin. 

 

Big Jon when you say “900” in the rear diff, is that the Tamiya labeling system for weight? The 60k up front makes sense to me (I have lots of different diff oil weights from 5k to 500k). 

 

Thanks!

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"900" refers to 900cst, which is about 80wt shock oil. For whatever reason, Associated rates shock oil in SAE weight, with the cst in smaller print in the label, and every manufacturer rates diff oil in centistokes (cst). All of my oils are Associated, so at least I'm comparing apples to apples when I'm trying to tune my junk.

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