501x Diff Balls

[MotoRev]

Hi,

Anyone know what size they are? Are they the 3mm by any chance? to fit the big pulley Worlds edition..

Thanks..

[steveproracing]

yes, they are 3mm on the big pulleys(and small pulleys)
oh and remember they use 12 balls in each pulley
and new packs tend to come in packs of 10.
hope this helps
steve

[MotoRev]

It does! thanks

[chrispattinson]

Run 18 balls in the diffs. Use the spare holes. Less wear on the diff, and you can run it looser and still not slip!

[simoncook]

Originally Posted by chrispattinson

Run 18 balls in the diffs. Use the spare wholes. Less wear on the diff, and you can rnu it looser and still not slip!

Is that really worth doing? I am planning a DB01 diff rebuild soon with the 501x diff halves etc.

[chrispattinson]

Definately worth doing in my opinion. Less maintenance, better performance.

[mole2k]

I had planned on trying that but I didnt have enough diff balls the last time I was rebuilding the rear diff!

[sim]

On the 37T pulley, there's only 3 extra holes so 15 balls total. I tried it, but it felt funny so I chickened out and took out the extra 3 balls before putting it back in the buggy. This was on the DB-01.

You've had good luck with yours so far?

[chrispattinson]

Its been running trouble free for over 1 year.

If you think about it in principle, there is no reason it wouldnt work better, providing your not concerned with the additional angular inertia of a few extra diff balls for spool up.

[i4n]

sim, my DB-01 diff's felt funny when I tried adding the 3 extra balls too. I chickened out and went back to normal.............

[sosidge]

Since the three holes on the 37T pulleys are on not in line with the 12 original holes there is "something weird" (that is the technical term) going on if you put balls in them.

[chrispattinson]

All of the diff balls are running on flat plates, it shouldnt matter which track around the flat plate they are running on. I will continue to use the diffs as I have them, I find they handle the power better. Im sure anyone that saw my car on the track yesterday can vouch that the handling is very good, and that is with additional diff balls.

How would you describe the 'weird diff' feeling?

[MotoRev]

Wouldn't there be an un-even pressure spread across the plates under differing loads? i.e during acceleration/braking in sharp corners as opposed to the 12 ball's all being evenly spaced and centered...

If that makes any sense at all!

I know what I mean anyway

[AaronR]

So, in a nutshell , when it comes to balls, don't mess with the factory setup! Ugh, such a bad American joke!

[sim]

It felt smoother with the 12 balls. With the 15 balls, it was strangely gritty, like it was just running on the 3 balls and the other 12 were disengaged. It was just an experiment for me as I only had 24 balls (so I borrowed 3 from the other diff while I messed around building the first one). These were ceramic balls from JAAD.

The problem was very likely just the plates. I don't remember if I ran new ones or flipped them around or just chucked the new balls into the old grooves. I think they would work after breaking in, but with the 37 tooth pulley, I figured the extra 3 balls so near the centre wouldn't have made a huge difference so I didn't bother ordering more balls.

Some of my friends who run the TRF415 swear by the extra balls though. I think they go from 8 balls to 16 though (TA-05 original pulley, 501X ring), so that's a huge jump in ball count (that's an official term)

[davesrc]

I would recommend everybody to change the tamiya lightweight diff balls for ceramic!

I race indoor on polished floor and had to rebuild diffs after every meeting as they were very rough!

I upgraded the standard diff balls to ceramic and have raced 15 meetings without touching the diffs! Also change the m2 bolt and lock nut in the diffs, so once they are set they wont loosen!

(using the tamiya diff covers to keep dust out)