I have the UE 6 spider diff's and I have a hard time to
understand the ratios on these for my MMM 2200KV comb.


How do I gear to get optimal balance for the heat and speed factor.

If I compare the stock diff's with the UE 6 spider diff's in a let's say 68T spure setup, how many tooth would you thnik distinguishes on the UE diff compare to the E-Maxx 3905 original diff's?

I will run both 4S 20C and 6S 25C

UE describes it this way

These do lower your overall gear ratio, you will need to gear your truck up.
Maxx R&P ratio is 2.85:1
7.5 R&P ratio is 3.31:1

For this reason you must upgrade both ends of the truck at the same time.
Do not try to mix ratios.

If running 22/72 with the Maxx ring and pinion, 23/65 would be the identical
ratio with the 7.5s
I’m running 22/66 at the moment. It has tons of bottom end, but feels like
it could use some more top. Though there is no question the truck is fast even
on a large track. (I had a 23 but it had a problem and I’ve not gotten it replaced yet.)