Losi rear diff - 10t in truggy and 13t in buggy. why?
 

so i was going to try my Fioroni tractive IV diff in the rear of my Losi 8t and it wouldnt sinc up with the gear in the diff case. but i have a tractive IV diff in the rear already in my buggy and it fits fine. so i opened it up and i noticed it was larger than the one in my truggy. my truggy rear diff pinion is 10t and the buggy is 13t. why is this? also, will this have the same effect as the center spur/pinion that if i put the 13t in my truggy instead of the 10t will it be faster? or will this only result in too much heat, etc. to run the Fioroni diff i have to use the 13t but will it be worth it. any help on this is appreciated.

I believe the different pinion size is to change the gear ratio to compensate for the larger tires

+1. You could run a Buggy pinion in your diff (IDK if you need to change the diff case or not, never tried it) and it would give you a taller gear ratio but you would have change out the pinion gear to get the ratio right.

Gear boxes are the same in the buggy and truggy. The pinion and main gear are different sizes for the buggy and truggy. If you want to put that diff in the truggy you would need to see if the main gear from the truggy will fit the diff you are trying to install.