Alto gearbox ratios

Tue May 19, 2015 11:15 pm

I found a bit of paper laying around where I'd scribbled down the ratio comparisons for various Alto gearboxes. Before I lose that bit of paper I thought it would be a good idea to add it to the site/forum!

From memory I calculated the theoretical top speed using the redline of an F8B, roughly 6500RPM. At the time I was interested to see if an import box would make any difference to cruising RPM. As you can see, despite an extra gear the F6A box has an almost identical final drive ratio, and therefore roughly the same cruising RPM as the F8B 4 speed. The obvious difference is the spread of gears.

F5A (5 speed)
1st 3.384
2nd 2.055
3rd 1.375
4th 0.962
5th 0.833
Rev 2.916
FD 5.937 / 5.538 (DOHC / SOHC)
Top speed - 135/145kph

F6A (5 speed)
1st 3.818
2nd 2.227
3rd 1.521
4th 1.030
5th 0.837
Rev 3.385
FD 4.705
Top speed - 170kph

F8B (4 speed)
1st 3.583
2nd 2.166
3rd 1.333
4th 0.900
Rev 3.363
FD 4.350
Top speed - 171kph