i ember haveing simalar problems with a kart project, those litel drive sprokets off bikes are hard as hell if the shaft is softer they soon wear the splines off the shaft.
i have various ideas sutablity of massivly depends on the power being handeld. on the kart it ended with the shaft over length and the bearings on the outside so they were easyer to change, the finl way we attched the gears to the shaft will e frowned apon but after trying to do it corectly twice and failing the spokets just got welded on as wanted to test the rest and got inpatient it worked to well to the point it got left
i have various ideas sutablity of massivly depends on the power being handeld. on the kart it ended with the shaft over length and the bearings on the outside so they were easyer to change, the finl way we attched the gears to the shaft will e frowned apon but after trying to do it corectly twice and failing the spokets just got welded on as wanted to test the rest and got inpatient it worked to well to the point it got left