The tire size has nothing to do with the rim originality

Look on the inside of the spokes for markings
And ur tire should b 275/40/20 for the front and 315/35/20 at the rear 9.5 inch front width 10.5 inch rear rim width

__________________
04 black on sapphire 4.8is personally put 90,000kms
fully loaded minus the fold out trunk floor
-20' DUB X10 3 piece rims staggered setup
-LED angel eyes + interior lights + e70 style shifter
-AFE stage 2 intake system
-x-pipe/resonator delete
-UV coat windshield
-rebuilt Pano roof
-dynavin N6
-all front and rear end suspension parts and both front cv shafts replaced
-OEM hitch

And 2007 GSXR750