This small tool allows you to easily experiment with the effect of different transmissions, final drive ratios and tyre sizes to the speed of your car in different gears. The graphs drawn by the tool visualize the relation between the engine rpms and car speed. A separate form also shows you the maximum speed attainable for each gear and the engine rpm where the each gear starts after a shift up.

First, fill the tyre size you’re using to the topmost form - the default is the very common 195/50R15. After this, choose the transmission you’re using, set the final drive ratio (unless you’re using the transaxle default) and enter the engine rpm from where you’ll typically shift up. If your transmission is not listed but you know the ratios, you can type them directly to the form below the graphs. All the calculated values and graphs update automatically every time you modify the information on the forms.

Note: If you’re using staggered tyre sizes, enter the size used on the driven axle.

Tyre

Width (mm):		Profile (%):		Rim diameter (inches):

Ratios and shifting

Transmission:		Final drive:		Shift point (rpm):

	1.	2.	3.	4.	5.
Gear ratio
Top speed (km/h)
After shift up (rpm)

If you have ideas which you’d like to see on this tool or you’d like to have more pre-set transmissions on the list, please drop us an email and share your ideas and/or ratios of your transmission.