AS TIRE SIZE, WHICH YOU NEED TO INSTALL IT ON THE ORIGINAL RIMS ON HONDA GROM 125CC 4 STROKES IS 120/70-12, FOR FRONT (12 INCHES OF THE OEM RIM) AND FOR THE REAR IS GROM 130/70-12/14070-12 AND PLEASE NOTE THAT ANY FATTY KITS SIZE 12X8 - 12X4 AND 13X8 - 12X4 SIZE FATTY KITS ARE DESIGNED TO BE INSTALLED ON A HONDA GROM 125CC 4-STROKES WITHOUT A CUSTOM SWING ARM BEING MADE TO WORK AROUND THE WHEEL AND ALTHOUGH THEY ARE TOO WIDE RIMS, SO THE ONLY OPTION IS 12X6 - 12X4 OR SINGLE, UNFORTUNATELY!
ALSO, DON'T FORGET WHO NEEDS HIS OWN HUB THAT WE HAVE ON OUR WEBSITE TO A COMPLETE KIT INCLUDES HIS FRONT HUB 12X4 (4X12MM) AND ITS REAR HUB (4/110 OR 4X102), WHICH ALLOW YOU TO INSTALL A 12X6 OR A 13X6!