Straight cut drop gears are the most durable arrangment that can be fitted to a transverse A-series powerunit. These 3 gears are responsible for transferring all the Hp from the motor to the gearbox, so their longevity should be a top priority for any serious engine builder. In addition to the durabilty of a straight cut arrangment you get the added benefit of less Hp loss due to reduced side loadings in this critical area, which in turn minimizes the wear on the idler thrust washers. The Evolution gear sets are all built around a 30 tooth idler, which means that to change ratios, only the input gear and/or primary need to be changed to accommidate a wide variety of ratios..
The best straight cut drop gears are those with roller bearings on the idler gear. You can now upgrade from the stock S/C drop gears by simply replacing the idler gear. This gear fits into the gearbox and flywheel housing without the standard bearing. This does NOT fit the latest A+ type with larger idler bearings. Evolution Straight cut 23 tooth 1275 primary gear.
Ongoing development and investment of bringing parts up to date from yesturyear with current technology Mini Spares have introduced new EVO straight cut drop gears. With new 2 ring identification marks and part numbers they are not interchangable with previous drop gears as they have different profiled teeth with a shot peened finish for extra strength giving much more durability and quitness. More efficient as there is less power loss transmitted via gearbox and drop gears.
Achievable drop gear ratios when using our Evolution gears:
22 tooth primary - 30 tooth idler - 25 tooth input = 1.136-1
24 tooth primary - 30 tooth idler - 24 tooth input = 1.0-1
23 tooth primary - 30 tooth idler - 23 tooth input = 1.0-1
24 tooth primary - 30 tooth idler - 25 tooth input = 1.0416-1
23 tooth primary - 30 tooth idler - 24 tooth input = 1.0434-1
22 tooth primary - 30 tooth idler - 23 tooth input = 1.045-1
23 tooth primary - 30 tooth idler - 25 tooth input = 1.0869-1
22 tooth primary - 30 tooth idler - 24 tooth input = 1.09-1
24 tooth primary - 30 tooth idler - 23 tooth input = 0.958-1