Open quad rental Please opinions?

Hello to the round, I play with the idea to open a quad rental. For the start would be 10x Kymco Maxxer 300 with 20 hp. New 3500 Euro / piece So 35,000 Euro, few helmets and other, makes about 40,000 Euro money is available place right next to the S-Bahn is abundant, city center Munich there are 6 kilometers uncle in retirement has a lot of time, would handle the rental. He is happy if he comes among people and was merchant. Next competitor/ rental company is 3 0 kilometers away and charges 110 euros per day. Demand in summer is plentiful. (Munich) A hobby – retired mechanic from time to time would be necessary. (maintenance etc.) I would charge approx. 60 euros/day ??, with longer rent a little less. Helmet unique 5 euros rent, small cattle also makes crap. Insurance is just my turn, is not so easy to find a good price. Per quad 60 euros x 150 (realistic) rental days makes 9000 euros per quad/year. Ollerleih, if the demand exists. Was just in Greece, there works the magnificent. Must also in Munich work well. Holidaymakers.. and who just likes Quad. In winter is probably dead pants. Do I have thinking mistakes in it? The number of pieces can also be expanded.