Not sure what solder exactly, i just bought it from the electronics place. Its 99.3% tin and .7% copper if that helps
. Good to know about the mgm, i'll make sure to do that. With the gearing, i had no idea where to start because AFAIK there are no others trucks with the same ratios as this, so i just picked 16t, i didnt think id be THAT far off the mark
I think i might try fit a 50t spur on, to get this gearing thing sorted, i might have to notch the frame rails though. I'm still not sure... I could mod my motor mount to accept a 14t pinion, but i dunno if that will be a big enough drop.