I am in need a big diff for 1/8th scale. It would be a bonus if it had an optional aluminum case from the after-market. Another bonus if it has a smaller tooth count like 41-45t. Neither of these are needed. It has a big space to fill between the bearings. It will take the place of a general silicone diff.
The ofna ultra diffs are the biggest I know of. They do have optional aluminum cups, but unfortunately are 51 tooth spurs. I used one as a direct replacement for an LST tranny. The ends of the output shafts were actually 2-3mm wider than the tranny.
I don't have any on hand to measure for you, sorry.
It's "Dr. _paralyzed_" actually. Not like with a PhD, but Doctor like in Dr. Pepper.
Mod 1.5 pinions are okay as long as they will fit a 5mm shaft. It doesn't need to be very extremely strong, it just has to fill a large space between the bearings. If it is alittle short I can shim it.
Also I wish I knew what spur gears from different manufactures would fit what cases. In other words mismatching spur gears and cases.
I have discovered that with alot of shimming both the HPI/HOTBODIES and OFNA 7.5 diffs will fit. I need to order some shims. I am the hotbodies diff has an optional 40t spur like I want but it can never be as awesome as the OFNA 7.5 diff with its 8 gears and nice 2 part case. What I want to know is if the OFNA hyper 9 8 gear spurs will fit the 7.5 diffs? The hyper 9 has a 40t spur. They have the same 6 bolt pattern.