Stronger and longer lasting. Any time you can run a larger bearing for something, it's better in general. Even with the same spec bearing, the larger one will more than likely last longer since each ball inside makes less revolutions causing less wear and heat.
For RC's on axles, larger bearings last longer too because of more contact area for the bearings to support the constant side load pushing on them.
Traxxas later model carriers actually run a larger bearing now. At least on the revo/slayer/t-maxx. I noticed it when I was buying new bearings for my used slayer. They are larger than the earlier revo/revo spec t-maxx/slayor's had.
I run the true track on the rear of my slayer converted to revo now with RPM arms up front and older carriers up front. I'll upgrade the front carriers at some point... but I have the two spares from the rears to use yet. I really like having the true-tracks. Gets rid of a pivot ball and tie-rod which removes failure points for a basher like me. They have held up really well over the past couple of months so far.
