Tire size help

[althezenman]

I need some help determining if I can use Coker Fiirestones on my hardtailed bobber (formerly a 1982 CB750 Nighthawk). The Nighthawk has the solid "star" mags instead of the usual Comstar mags, along with different stock tire sizes than most DOHC CB750 bikes. I think using them with tubes will be fine but I can't figure out the correct size for the Cokers. This is what I want to do:

Stock Front is  120/90/18 and I want to use a 4.00/18 OR 4.50/18 Coker
Stock Rear is 140/70/16 and I want to use a 500/16 Coker

Does anyone know if there are issues with this swap?

Thanks

[TOOLS1]

Front Tire Size Conversions Rear Tire Size Conversions
Metric Alpha Inch                Metric Alpha Inch
80/90 MH90 2.50/2.75        110/90 MP85 4.00/4.75
90/90 MJ90 2.75/3.00        120/90 MR90 4.50/4.75
100/90 MM90 3.25/3.50        130/80        5.00/5.10
120/80        4.25/4.50        140/80        5.50/6.00
120/90 MR90 4.25/4.50        140/90 MU90 5.50/6.00
130/90 MT90 5.00/5.10        150/80 MV85 6.00/6.25
                                                        150/90 MV85 6.00/6.25

This should answer your questions about tire size. Since you have mag wheels, you will not need to use a tube.
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