Lots has to do with the track, and the surface.

Most people will use a spool front and a normal diff at the back. This is a good setup if you have lots of traction, and a tighter track.

On a looong sweeping track, with not as much traction a tighter rear diff, and front one way is great on a stock car. In this format though, you will have difficulty braking. This setup is perfect for the Al-Ain track.

The best starting point will always be wht the manual says, and then make adjustments from there.

Bear in mind, the tighter you make your diffs, the more difficult it is for the car to turn, you will experience understeer, and tightening up the diffs puts a LOT of strain on all the drive components. It is only good on the front diff, in tight tracks.

My advice for unknown surfaces is neutral setup (Automodx).

Take care when building ball diffs, the thrust bearing needs AW grease, the balls need diff grease. The balls must rotate smoothly over the diff plates, any rough movement (sandy) or out of alignment (tighter in some places) and you will need a rebuild.
The diff action should be that when both diff halves are held still, you should be able to move the gear, but not easily. It should require some force. (Have it a little looser will result in a Limited Slip Diff scenario..a different kettle of fish altogether)

I used to be a FOW user.
But once I got to understand how the COW works, I don't think I'll be switching back to FOW anymore.

...Josh, how does it work?

...I've already bought a FOW

HOW TO LOCK A PLANETARY GEAR DIFFERENTIAL

Before attempting this yourself, you need to know that if ANYTHING goes wrong, or if anything breaks, you CANNOT blame me for it. You are actions are not something I can be held responsible for.
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The job of the differential, in simple words, is to allow the wheel it is connected to, to rotate at different speeds. And that increases traction which in turn prevents the tail from kicking out during turns.

This is what a TT01 differential looks like:


There are a few ways to lock such differentials.

1) To permanently lock it using a DIY method (very reliable! Impossible to unlock it during a run!)
2) To temporarily lock it using a DIY method (less reliable)
3) To temporarily tighten it using a DIY method.
4) To buy a direct drive, spool, diff locker (lots of terms) to lock it. (very reliable, it MIGHT break if you use 3rd party ones).

Now on with the tutorial.

Method one: Temporarily lock it:

To temporarily lock the differential using this method, you need the following things:

1) Nitro fuel tubing.

I'll be using the TT01's differential as an example.

Step one: Remove parts MA13 and MA11.

Step two: Place the two pieces of fuel tube before the MA13 and MA11. the only goal here is to stop the planetary gears from turning, essentially creating a spool diff that would normally cost a pretty penny.


Step 3:
Just pop everthing back in it's place, leaving the nitro fuel tubing in between. If it's too tight you can always trim the fuel tube a little to get the perfect fit. Reassemble the chassis and your all done. Now when you turn one wheel the other should turn at the same time.

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Method 2: Permanently lock it:

To permanently lock it using this method, you need the following items:

1) Strong glue. (JB Weld, hot glue gun, etc.)
2) Adult supervision is strongly advised. Hot glue guns, etc. Should be handled with care.

Step one: Remove GB4 and MA12 from the differential. Everything seen on the left side of the picture should stay in.

Step two: Add lots of hot glue into the left side, making sure that MA13 and MA12 are completely covered. Do not add too much, otherwise it might become really hard to re-assemble the differential.


Step three: Re-assemble the differential.

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Method three: temporarily tightening it.

To temporarily tighten the differential, you need the following:

1) Nitro fuel tubing.
2) Scissors.

Step one: Cut some nitro fuel tubing (has to be the right size) and place the little pieces in FRONT of the MA13 gears. So the fuel tubing is in between the MA13 and the center of MA11.

Step three: It should be a VERY tight fit or it will not work. Re assemble the differential as you would normally. Make sure the nitro tubing is in BETWEEN all the MA13 and the center of MA11.

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*Planetary gear differentials are mostly found in entry level kits. Such as the TT01, HSP flying fish, etc.
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For now, that is all. Will post a tutorial about locking ball differentials tomorrow.

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For one, it leaves you with NO brakes whatsoever, not good if you are on a tight track, but useful on an open track tht speeds allow you to get by with no brakes.

Al-Ain would maybe qualify, but only in a class where the top speed is not RIDICULOUS-speed.

Ahh..I see. Thanks.

Never mind, I think I need breaks, helps you when you screw up that transition on the S-curve.

Oh yeahhh...Sorry, forgot.

Well, I haven't tried the FOW on road, ever..So guess I'll find out when I get it...I just hope I don't hate it.

Cheers.

Spool: Less turn in when entering a corner, good when exiting corners.
Benefit: You can brake very late, used on tight (indoor) track.
Disadvantage: lots of strain on the drive train and understeer.

One-Way diff: More turn in on corner entry and exit, more steering overal.
Benefit: higher corner speed, used on big flowing track.
Disadvantage: can't brake late and not in corners.