Hello,
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?
TIA
Fred gurgled happily, sounding much like they were saying:
Both.
Entirely up to the design. At one time many cars had only three speeds. Didn't mean top gear was the equivalent of third on a modern 5 speed.
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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 !
70mph in 6th on my car is 3000rpm.
70mph in 5th on my car is 3000rpm.
Likewise in my Capri.
70MPH in 6th in my Mondeo TDCi is 2000RPM
But 6 is old hat. Now some cars have 7.
Pointless. Lorries have been going the other way moving from 16 for an artic typically down to 12 now.
Depends. :)
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.
Depends. I only need second and fifth in my manual five speed for forwards travel. I happen to benefit from first, third and fourth too...
My 1981 Fiat 132 proudly announced: "5 Speed" on the boot lid :-)
60mph in 6th on my car is about 3000rpm.
Elder gurgled happily, sounding much like they were saying:
70 in 5th is 2600 around these parts... Right about where the boost starts to come on strong. Lovely.
I tend to go 1,2,6 on clear roads. 1,2,4 if I family playing a bit.
Elder gurgled happily, sounding much like they were saying:
Doesn't that kinda defeat the point of having a six-speed box?
Might as well just have four well-chosen ratios in a lighter, simpler box...
70 in 4th is 2600 in mine, I've only got 4 gears.
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.
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