I was replacing my sprockets and all of the rear sprocket nuts went on fine except for the last one. It just keeps spinning. Is the nut, bolt head, or hub stripped?

The bolt head is round and has a flat spot where it should rest on the hub, but it just keeps spinning around when I try to tighten the nut with a torque wrench. This leads me to believe that maybe the area on the hub where the bolt head is supposed to rest is stripped or something.

Any ideas?

My bike is a 2004 cbr600f4i

 

It's supposed to lock in the carrier and not spin. As the flat spot comes around, jam a flat head screwdriver between the carrier and the bolt to stop it from spinning. If all else fails, you ay need to cut off the nut and replace the bolt and nut. Hopefully the carrier isn't too damaged to hold the nee one from spinning.

 

Could I also use vice-grips to prevent it from spinning, and then torque it down?

 

You can try. There is not much there for the vice grips to grab on to, but try it.

 

If your sprocket is steel you can tack weld bolt head to sprocket. Remove nut, grind off tack weld and remove bolt. Inspect sprocket for damage and replace necessary parts.