GDS Racing 8mm Shaft MOD 1.5 M1.5 Pinion Gear for FG/HPI/Losi & More (17T): Toys & Games. GDS Racing 8mm Shaft MOD 1.5 M1.5 Pinion Gear for FG/HPI/Losi & More (17T): Toys & Games. 17 Tooth 。 MOD 1.5 (M1.5) 。 Bore size: 8 mm 。 Total height: 16 mm 。 Size:17T 。 The gear was made of cased hardened CR Steel then carbonizing the surface.。 It's has very tough core inside and high hardness on the surface for wear-proof. 。 。 。