Further to my previous post. I looked at the Coker tire website. It clearly indicates that there was a 175R13 original option to the listed 6.70x13 tire. The service manual states that a tubless was optional, so I guess the R in the 175R13 indicated that the optional tire then was a tubeless radial. Does this sound right? Thanks.

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Douglas
1959 M-B 220S cabriolet