gearing for 8xl in maxx ?

[Patrick]

It doesn't matter if it's 32p or mod1, either way it's the same ratio.
What numbers are you using in the calculator? Because I got an estimate of about 44mph with that gearing (11.7:1 fdr) on a feigao 8XL, which I think could be a bit high for normal use.
19/54 should be ok if it fits, but 22/54 would be around what you need to do 40.