I've got a 1972 CT70H K1 and want to replace the original 4.00/10 tires with a street tire. I've read all of the threads and it seems that most of the recommended replacement sizes are closer matches to the 3.5 x 10 OEM tire found on some models.
By my calculations, the stock 4.00 x 10 tire equates to:
Diameter = 18"
Width = 4"
Height = 4"
The closest metric conversion to this would be either:
110/90/10 (a size which virtually doesn't exist) or
100/100/10 (again, not available)
Here are size combinations that were suggested from the various threads. I've limited them to only those that will fit the CT70 without rubbing and that do not require modifications whatsoever.
Size Diameter Width Height Front/Rear
120/70/10 16.6" 4.72" 3.3" Front
130/70/10 17.2" 5.1" 3.6" Rear
100/80/10 16.3" 3.93" 3.1" Front
120/70/10 16.6" 4.72" 3.3" Rear
110/80/10 16.9" 4.33" 3.4" Front & Rear
100/90/10 17.1" 3.93" 3.5" Front & Rear
120/90/10 18.5" 4.72" 4.2" Front & Rear
Based on the above, the 120/90/10 is the closest tire to the 4.00x10. It should fit without a problem and because the diameter is closer to OEM than any other tire, the speedometer should be relatively accurate.
Just my 2 cents. What are your thoughts?
By my calculations, the stock 4.00 x 10 tire equates to:
Diameter = 18"
Width = 4"
Height = 4"
The closest metric conversion to this would be either:
110/90/10 (a size which virtually doesn't exist) or
100/100/10 (again, not available)
Here are size combinations that were suggested from the various threads. I've limited them to only those that will fit the CT70 without rubbing and that do not require modifications whatsoever.
Size Diameter Width Height Front/Rear
120/70/10 16.6" 4.72" 3.3" Front
130/70/10 17.2" 5.1" 3.6" Rear
100/80/10 16.3" 3.93" 3.1" Front
120/70/10 16.6" 4.72" 3.3" Rear
110/80/10 16.9" 4.33" 3.4" Front & Rear
100/90/10 17.1" 3.93" 3.5" Front & Rear
120/90/10 18.5" 4.72" 4.2" Front & Rear
Based on the above, the 120/90/10 is the closest tire to the 4.00x10. It should fit without a problem and because the diameter is closer to OEM than any other tire, the speedometer should be relatively accurate.
Just my 2 cents. What are your thoughts?