PBI Sprockets Aluminum Honda Grom Rear Sprocket PBI USA Rear Sprocket for the Honda Grom and many other Honda style engines is manufactured from aircraft quality 7075 T651 Plate Aluminum. Harder than steel and far lighter to save on unsprung weight. A division of Chris Products, Made in USA! PBI Sprockets Honda Grom Rear Sprockets are available in 31t, 32t, 33t, 34t, 35t, 36t and 37t options (see Related Items for our 60t Grom Wheelie Sprocket)! Please choose from Black, Blue, Orange, Red and Silver anodized color options! Select colors on sa le; All Blue Gear options. The stock rear sprocket size on the Honda Grom is 34 tooth. You can go up to 35t, 36t or 37t to increase your acceleration at the expense of top end speed. If you go down to the 31t, 32t or 33t you can get a higher top end speed at the expense of acceleration. A few rules of thumb with gear ratios for sprockets are as follows: Drop teeth on front/add teeth to rear = increased torque, increased acceleration, wheelies, racetracks with short straights Add tooth on front/r educe teeth on rear = increased top end speed, open road cruising, lowers RPMs, better gas mileage, tracks with long straights 1 down on the front is like adding 3 teeth on the rear The bigger the rear sprocket, the lower the gearing and the faster the acceleration Please click here to view our Gear Ratio Chart! Available in 31 Tooth - 37 Tooth Size Options (For 60 Tooth Wheelie Sprocket see Related Items)Available in Anodized Black, Blue, Orange, Red and Silver Color OptionsAircraft Quality 707 5 T651 Plate Aluminum Harder Than Steel & Far Lighter Extended Wear Resistance Fits #420 Chain Inner Diameter: 58mm Diagonal Bolt Hole Spacing: 89mm A Division of Chris Products Made in USA!