Steve do you have specifics as to what is commonly a challenge? Better yet - do you have a recommendation for another car as backup? I got this car almost for free so I figured I'd try it out. I considered using an HRS2 chassis but initial fit checks made it seem a lot less hassle to use the stock chassis. What I did to the 512BB so far:
-- Swapped out 32k@14.5v motor for broken-in Slot It Yellow-bell tach-measured as 24,800@11v, geared at 10/32 for an estimated 7,750 top rear wheel speed.
-- Shaved some metal off the motor can b/c the stock position for the rear bushings was slam up against the can and jammed the rear axle. Poor design of the chassis - they had plenty of room to have put the bushing mounts well away from the motor but I guess they were in a hurry!? Stock plastic bushings were very flimsy and I guess let the motor fit fine and not bind the axle. The chassis is the typical thin, brittle, flexy styrene, similar to Scalextrics.
-- Hollow rear axle and 15x8 rear wheels with P6s for shakedown runs and F30s for racing.
-- Kept stock front axle & hubs b/c the stock front tires have similar profile (and compound?) as NoGrips (and the hubs will explode if I try to pull them off - they are glued on extremely tight!) Front axles comes with stock 6mm grub screws and height adjustment slots.
-- Replaced guide with wood guide, plus new motor wire with eyelets.
-- Trimmed chassis edge slightly to remove contact with body. ....but you cant get much float on this body b/c of the 4 sided body posts. No weights at this time. Full RTR weight not yet verified.
-- Had to trim bottom of the cockpit insert to allow wires to be routed and to ease body mounting (it is very finicky out of the box).
