Gear change

davyjose

I presume this is the right place to post this thread. Just wondering, what's the optimum time to change up a gear, in reference to speed. Is it as high revs as possible maybe?

peasant

In most petrol cars peak torque is somewhere just above mid-range and peak hp near the top of the rev band.

When accelerating hard, you want to rev it so high that the revs don't fall below peak torque in the next higher gear ...but not too high, because then you'll go past peak hp (and hit the rev limiter:D )

If it's economy you're after, you want to stay between about 1500-2000 revs and wherever peak torque is.

What speed you're doing at those revs depends very much on your engine/gearbox/wheel size combination and varies between cars ...so there is no general rule that says "change into 5th at 43.75 km/h"

Andrewf20

Diesels can be a bit more tricky, as the punch usually kicks in at lower RPM then dies a death higher up the rev band. But at 70mph, to be in the sweet spot (about 2200rpm) in the diesel I drive, I would stick it in 5th, but then the gearbox divides up my engines torque even more.

maidhc

I normally change up (diesel focus) around 1700rpm. I'm in 5th from about 50mph. 5th does about 33mph/1000rpm.