It is unfortunate but most slot car racing wheels and gears are supplied with frankly sub-standard  setscrews. Electric Dreams has traced and obtained much higher quality setscrews, like no others, so that you may now replace the often defective parts. No more stripped wheel or gear hubs with these, they will fit tighter in the threads and are self lubricating. Sold by packet of 10 re-usable setscrews.