Well using a 40t Spur, 30/40 the gap is only 37mm vs the 36.5mm I have on my truggy. I think 30/40 should work just fine. I mean .5mm is easily shaved off the mount if need be...
My concern is also that single screw, is it enough to hold like a 1717? or another big type motor. The old one just felt more secure for the motor in my opinion. and more gearing also..Hope mike gives me an answer..