Tyres for 13" Midget Rostyles

[AndyPap]

I'm sure I've seen is somewhere but for the life of me can't find it, so...

What size tyres would I need to put on 13" Midget Rostyles to match the rolling diameter of a standard Minor wheel (so that I don't mess up the gearing or need to recalibrate the speedo? I think the Rostyles are 4.5" wide

Thanks

Andy

[bmcecosse]

I think 165 X 70

[mike.perry]

145/80/14 Circ = 72.7" Rev/Mile = 872
155/80/14 Circ = 84.9" Rev/mile = 849
165/70/13 Circ = 69.4" Rev/mile = 913
165/80/13 Circ = 73.5" Rev/mile = 862
175/70/13 Circ = 71.1" Rev/mile = 891
175/80/13 Circ = 75.5" Rev/mile = 840

Therefore if you are running 145/80/14, the closest 13" tyre is 165/80/13.
155/80/14 = 175/80/13

[bmcecosse]

175 is far too wide on a 4.5J wheel....... even 165 is 'pushing' it............

[mike.perry]

I like a bit of wobble in the sidewalls