Called Michelin and talked to someone in Europe who told me the 4mm tubes where good for on and off road. After hanging up the phone, I realized I hadn’t asked about shelf life, so I called back and this time I talked to someone in North America. He told me the 4mm tubes where rated for off road and would get warmer than a regular tube if I used them on road. He suggested, I go with on road Michelin 19MF 1466 inner tubes but couldn’t answer my question on shelf life. So, don’t know who to believe and therefore exchanged the 4mm for a set of 19MF 1466. Thanks to everyone for your input. Cheers.