Leading A-Series engine specialist since 1981
If you already have one of our high performance straight-cut drop gear sets and require a change of ratio, a change of engine type or just some spares, we can supply any gear from the kits separately.
We can supply;
Please note that spares are only compatible with the straight-cut MED gear sets.
All are interchangeable within the sets, so you can upgrade to a roller bearing idler from a standard pin type, or change idler and primary gear ratios.
The MED drop gear sets are available in three different ratios, which can be used to tweak the final drive ratio. Changing the effective final drive ratio will either improve acceleration or top speed potential, although one will always come at the expense of the other.
We can do this by changing the tooth count on either the idler gear or primary gear to 23 or 24 teeth. The idler gear in the middle remains at 30 teeth regardless.
The table below shows the various tooth counts and the effect on the drop gear ratio:
|Drop gear set configuration|
|Input gear||24 teeth||24 teeth||23 teeth|
|Idler gear||30 teeth||30 teeth||30 teeth|
|Primary gear||24 teeth||23 teeth||24 teeth|
To calculate your effective final drive ratio based on the above, simply multiply your existing final drive ratio by the number of the drop gear set. So for example, a 3.47:1 final drive ratio with a 1:1.043 drop gear set then becomes 3.62:1. Remember that the higher the number, the shorter the gearing will be, so this change will result in a higher engine RPM for a given speed.
Changing the primary gear is easier than removing the differential to change the final drive ratio, so racers use this to adjust their gearing to suit different circuits. Keeping an engine in its peak powerband for longer will result in a faster lap time.
See the following table for our final drive conversions using the various drop gear sets:
|Drop gear ratio adjustment|