These spacers are essential for anyone wanting a tight fit with a bbshd. I have a very wide chainstay on my plus size bike, but it only has a 73mm bb. The 68-73 bbshd wouldn’t fit so I had to go with the 100 mm version. When I received it I was shocked by how wide it was and thought you I’d never be able to get it tight enough without so it wouldn’t slip. But thanks to five 3mm spacers and a little ingenuity, my motor is solid and will not slip. I couldn’t have done it without these spacers. Luna rocks!