I'm from Turkey and the cafe racer style is not so popular or known in my country. So I need your valuable suggestions for my cafe racer project. I just bought a 1977 BMW R60/7. Original tire sizes are 3,25 S19 Front, 4,00 S18 Rear. I wanna replace the rear tire with bigger size. They says that (service guy) I am not able to install bigger tires. But I saw a lot of bikes on the internet, without any modification. I would like to ask that is there anyone who has some information or suggestion to me about the biggest rear tire size that I can use ?
Thank you in advance.