Originally Posted by
teknorc
This is spot on. ALWAYS ream your arms when building the kit or installing new arms. We ream them out until the hinge pin can fall through on its own (~4.2mm). This ensures the suspension can do what it needs to do all the time even if a little dirt gets in. Don't be concerned with 'slop' in this area because if the arms are binding for any reason, the car will not handle correctly.
just have checked the hingepin/ arm play on the truggy after a few runs and you are right, they needed to be reemed out...
On my old eb48 i have never reamed the arms and they had enough play, but the xt arms also needed to be reamed.
checked also 2 pairs of new "old" non xt arms and they are fine without reaming.