mbx5 gearing

[CerberusVI]

So i just finished converting a mbx5 to brushless and i had a couple of questions...I tried running 12/46 gearing and it was far too slow around 22mph, so the only other pinion i had laying around was a 21 which would gear it for around 38mpm. Speed on the 21 was where i would like it to be but my setup is a little goofy

I know with such low voltage the motor is turning some pretty low rpms and with such high gearing its working the poor mmp. How well can the mmp handle the abuse? Should i just buy a 4s and gear back down to be safe? or will i still be stressing my setup?

i drove it for about 15 minutes this morning and took temps 77 @ motor, 109 @ esc, 70 @ lipo. It was about 50 out this morning, but i plan on doing more temp checks when i get home from work, supposed to be 71 today


Setup;
Mugen mbx5 Buggy
NeuCastle 1512 1800kv
Mamba max pro