Originally Posted by
FauxMako
I haven't see anyone break any hubs or arms. Spares are never bad, but unless you are breaking them on other cars in your class you may be able to skip them.
Haven't verified it personally but a chart was posted here:
http://www.rctech.net/forum/9694373-post651.html
of all the possible gearing combinations that would mount up.
As far as slotting screw holes to loosen up the front belt that only ones I can think of slotting would be the spur gear shaft screws. I'd be worried slotting the holes for the spur gear shaft that it would end up running at an angle and cause gear mesh issues. The force of the belts pulling one side to the front and one side to the rear would be trying to rotate it all the time. Could cause some binding as well.
Some have posted that the belt that comes with the Zero S kit and the belt you get when you order the option part aren't the same belt. Haven't confirmed that either.
I solved it with the alum spur gear holder and 19T pullies. Side effect is that it makes your IDR 2.0 and all that math becomes so much easier
19T pulleys works, and I can say the replacement belt is different then the kit belt. Same number of teeth, but with the 19t pulley and the replacement belt, and I have a ton of adjustment. I am set right about in the middle of the diff adjustments right now with a very loose belt.
The 19t center pulley seems a better option then the 37t diff gears, as replacing the spur gear mounts is another good upgrade, and you are right there for the center pulley set. It also gives you an IDR of 2.0, which makes FDR calcs easy.