Unless you have prior experience of long-distance bike rides, it is not recommended to go for bike trips around Manali on your own. Additionally, it is safer to go with an operator you’ll have a back-up vehicle tailing you with a professional mechanic and all the spare parts. The back-up vehicle will also carry your gear.
Also, the operator knows the route better than anyone so they will help you navigate it without any hassle and in case of an emergency, you’ll always have them around to help you.