I see that some cars are advertised as having six speed gearboxes. I think this would be useful because in my five speed car, the engine revs at 70mph A-road or motorway speeds and I think it would be good for fuel economy if I could change into an extra gear. Is that what the sixth gear is for, or are the gears closer together in a six speed gearbox? Would it still be high revs at 70mph?
agreed, my MX5 sport has a higher top gear than the 5 gear one which does help a bit on the motorway.. I almost over revved the engine once by changing from 5 to 3, more used to a diesel !
The '04 9-3 SS has a five speed on the 1.8t and a six speed on the 2.0t. Both have the same top gear ratio (30 mph / 1,000 rpm). The six speed's other ratios are shorter and closer together.
Is there a good reason for squashing them closer together? Surely if you had too many gears, too close together, you would spend all your time shifting gears? That would appear to be why other posters have said they miss out gears and jump from 2nd to 4th?
Well, maybe. Comparing the Saab 9-3 1.8t and 2.0t, the 1.8t has the five speed 'box and the 2.0t has the six speed. Both have a top of 30 mph /
1,000 rpm. At first it feels a bit strange changing through to sixth gear rather than through to fifth, but after a few miles it becomes second nature. The 1.8t doesn't like fourth at 30, the 2.0t is happier; sometimes the 1.8t feels a little out of ratios if you're hypermiling it about. 45 is a little too slow for top if you're on any sort of gradient, but fourth feels a little too low a gear. Part of this is because I bought a 1.8t rather than a 2.0t of course, so I feel I'd want the extra ratio. ;-)
If people are block changing then this sounds like it's awkward to go 1, 2,
3, 4, 5, 6. In the 2.0t I found 1, 2, 3, 4 then 6 worked quite well, dropping to 5 for 40 limits and suchlike.
Just two. One for under 62. The other for over? :-)
To a point, six speed transmissions are more a marketing and carbon dioxide scam than a genuine need. Oh, wait, reducing the carbon footprint is a genuine need. My mistake. :-)
As these days I am invariably short-shifting the 1.8t at ~2,000 rpm every change, having more ratios would help over one of my commuter routes as it's hilly and curvy. Instead there's a hole between ~45 and 50, fourth and fifth gear... but that's just because I'm broke and trying to save fuel.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.