I actually like the Schumacher spurs. I've been able to carry a ton of them over since the mi3 leading up to my current cars since I've only had 2 fail over the years and to be honest I'd say it was probably my fault on both. As far as a ratio range, I can go from a 59 tooth spur to a 118 spur.....never had an issue whether it's a 4.5 or 25.5 motor. I actually think they hit the ball out of the park with these. Can't think of too many chassis companies who've made their own spurs that weren't going to be changed out for a panaracer or another aftermarket spur...kimbrough etc.