I just purchased a NOS freewheel style Mavic 550RD rear hub sight unseen which the seller claimed had English threads. It turns out that they are actually Italian thread 35mmX24 tpi. Will I be able to fit a normal English thread Shimano freewheel onto the hub? I haven't tried because I want to be able to give it back without scratches for a refund if it doesn't fit.
English thread freewheel to fit Italian thread hub?
- Thread starter daddyduca
- Start date
Thanks for the reassurance. Since posting my question, I found the following info on Sheldon Brown's glossary on the Net:
Italian threading is a curious mixture of metric and British. Diameters are specified in millimeters, but threads are in threads-per-inch! In addition, the thread angle is 55 degrees, like the obsolete British Whitworth system, rather than 60 degrees as with U.S. and metric threads.
Italian freewheel and headset threads are the same as British/ISO, except for the thread angle difference. They may be interchanged, but you should not go back-and-forth bewteen Italian and British components. Italian freewheels are basically extinct, so the issue is moot there.
This is why it works!
Italian threading is a curious mixture of metric and British. Diameters are specified in millimeters, but threads are in threads-per-inch! In addition, the thread angle is 55 degrees, like the obsolete British Whitworth system, rather than 60 degrees as with U.S. and metric threads.
Italian freewheel and headset threads are the same as British/ISO, except for the thread angle difference. They may be interchanged, but you should not go back-and-forth bewteen Italian and British components. Italian freewheels are basically extinct, so the issue is moot there.
This is why it works!
