Kyosho ST-RR Differentials - Just how tough are they?

[Gee]

Been having some diffuculties with my Savage XL differentials. With the price of cen diff upgrades going through the roof. I was rumaging through my boxes and came up with some STRR differentials. They might work in the savages. I have only stripped one of my STRR 10t bevel gears since I've owned the truggy. That was my fault aslo. Before I understood the why and how of shimming.

Anyone ever have problems with their STRR diffs? You think the spiral cut would hold up better on the heavy savage?