How many gears are too many?

[1991_Vn2nV]

With BMW, Mercedes, Lexus etc. now using 7 speed auto's, the 2009 BMW 7 Series will now be fitted with an 8 speed gearbox. Apparently Lexus also have 8 speed gearboxes in some models but im unsure which ones.

So with BMW using an 8 speed and Lexus too, I can see Merc joining the party pretty soon.

Realistically, what difference is an 8th speed going to have? Is it just about bragging rights?

And to think here I am stuck with a 4 speed

[CSP]

It's all about maximum performance and minimum fuel consumption.

Remember, most technology stems from racing developments. Race cars have had 7+ gears for a long time.

[tanka5.7]

its just like mountain bikes, when i was a kid if you had a 10 speed you where the ducks guts now they have like 28 gears

[88GreenVN]

Next they will be going down the Mack truck path with 18 gears and 14L twin turbo detroit diesel. Gotta luv 1 upmanship in the car stakes.

[Not_An_Abba_Fan]

Top gear, no matter whether it is 3rd, 5th, or 20th, will be the same 1:1 drive. Sometimes they will be a slight overdrive. The reason behind so many gears is to get maximum torque. If the ratios of the gears were close enough, you would only be operating in a narrow rev range so you don't lose torque on gear changes.

[tanka5.7]

top gear hasnt been 1:1 in a long time its an overdrive or even a second overdrive but you right about the toque bit

[f1tzy]

In the T56 4th gear is the 1.1 ratio and in the D173 its 5th

[CSP]

I have 6 gears and my 1:1 is 4th.

[azkwazere]

always wanted a 28speed box... that would be sweet.... youd jump like 4 gears at a time lol...

In all honesty, you can never have to many gears... always gives you more options...

aZk.

[ProphetVX]

Most of these 7 and 8 speed gear boxes are paddle shifts.

For that you can never have too many gears, gives you the most torque possible at any speed and isn't a hassle to change gears.

Performance and fuel economy in mind.

[burnz]

bring back the 2 speed power glide.

[Full Spectrum]

7-8 they would be wasted in Australia's lack of high speed highways.. Maybe on the Auto Barn but not on the Hume or wesgate.
6 speed with overdrive is fine. Hell 5 speed auto's are great.

[STEALTHY™]

Heres the ratios for Holdens T5 and T56

2.66, 1.78, 1.3, 1.0, 0.74, 0.50.
2.95, 1.94, 1.34, 1.0, 0.63

[Just_a_stocker]

its all 6 of one and half a dozen of the other..

new cars lot of em have 6 speed manual!!!

yeah right gime a break , whoe could be ****ed runing through 6 gears around town,, bet most dont even get out of 4 th,,

its a wank no doubt.

[Wombat]

Fuel economy and smooth running, pure and simple...the more gears in those autos, the better you can have the engine purring along in the sweet spot, using the minimum fuel for the best acceleration and economy. They are smoother for not having to drop so many revs between gears as well. They are getting closer to the idea of a stepless Constantly Variable Transmission, without the bad parts of CVT technology.

I would guess Holden autos will be seven speed before long...and not before time...

[vtdemon]

It'll all be CVT soon enough. 1 smooth, constantly changing gear ratio. You can't feel any shift points etc. cause there aren't any. They keep the vehicle in the best torque producing range throughout acceleration and give unbeatable fuel economy.

[STEALTHY™]

yeah right gime a break , whoe could be ****ed runing through 6 gears around town,, bet most dont even get out of 4th

Only someone who hasn't driven a 6 speed will say that. I regularly use 5th and 6th, and have no problems changing 6 times.

[CSP]

Only someone who hasn't driven a 6 speed will say that. I regularly use 5th and 6th, and have no problems changing 6 times.

I totally agree!!! I get 11 or 12 litres per 100km around town in my VE Clubby 6.0 litre cause I use 5th in 60 and 70 zones and 6th in 80 zones and above

[Reaper]

Only someone who hasn't driven a 6 speed will say that. I regularly use 5th and 6th, and have no problems changing 6 times.

Same. When I had the manual 6 slotter I used all gears. I quite often skipped one when conditions allowed though.

On the broader topic of this thread, it comes down to engine performance. With less gears, the engine is required to perform over a wider rev range. That is both in fuel economy and power/torque. With more ratios that rev range will be reduced allowing the engineers to design engines that are more focused, powerful and efficient.

Reaper

[Not_An_Abba_Fan]

My Outlander has CVT, love it. The only down side is the poxy exhaust note.

[Just_a_stocker]

Only someone who hasn't driven a 6 speed will say that. I regularly use 5th and 6th, and have no problems changing 6 times.

Ive driven a 6 speed,

[immortality]

Heres the ratios for Holdens T5 and T56

2.66, 1.78, 1.3, 1.0, 0.74, 0.50.
2.95, 1.94, 1.34, 1.0, 0.63

i thought the OD ratio for the T5 was 0.72 (i know the V6 is and i thought they were the same (V6 and V8) except that 1st in the V6 box is 3.25)

this is were diff ratios come into play.

when holden introduced the T56 they fitted 3.46 ratio diffs which equates to approx 1430rpm @ 100kph which is still a little low in the rpm band even for a V8. hence the reason you really should fit either 3.73 or 3.9's (standard HSV GTS ratio from memory) with a T56. on the other hand with standard 4 speed slush box, the final OD ratio of 0.7 which equates to approx 1780rpm @ 100kph and 1840rpm @ 100kph for the T5 (.72 OD)

as a few others have stated above, it's really about keeping the engine in a narrow as possible rev range where the manufacturer can tune it for best possible power/torque delivery with minimal fuel consumption and emisions.

increasing the number of gears reduced the RPM window required which means it's easier for the manufacturers to meet the ever increasing demands for increased fuel economy and reduced emisions that goverments put in place

3000th post

[commsirac]

Reminds me on an article I read recently...(within the last five years) where the writer condemned the 6 speed gearbox on the high performance holden they were testing. ie "the two top ratios are too low.....wasnt able to accelerate hard from 100km/h in top gear, not like say a GTHO which would pull hard in top gear all the way from 30-140mph"

Clearly, this person had no idea!

The top gears are there for economy at highway speeds, where the power demands are low, if you want maximum acceleration, change down.......that's the idea of having six speeds. Having the motor sit in the power band while on the highway will chew up fuel.
To design a motor that pulls hard from 1000rpm, will mean it would get quite breathless by 4000rpm and that the maximum power delivered from that motor would be quite small for its size(unless we have variable valve timing). Manufacturers get more power out of the same size motors now due to many factors,amongst that, getting them to spin faster.

The only -ve I see to extra gears is weight, cost and complexity/reliability.

[immortality]

The only -ve I see to extra gears is weight, cost and complexity/reliability.

very true. the T56 box is very heavy compared to lets say a T5 but it can handle a lot more power. the economy gained by the extra gear probably far outweights the physical weight factor of the extra cog in the box.

i'd like to think that by the time this kind of technology (6+ speed autos or manual) filters down to the mass produced vehicles like our commodores that it's well and truely tried and tested by the upmarket manufacturers like BMW and Mercedes.

[vlv8vic]

7-8 they would be wasted in Australia's lack of high speed highways.. Maybe on the Auto Barn but not on the Hume or wesgate.
6 speed with overdrive is fine. Hell 5 speed auto's are great.

Not sure i can agree with that, like stated it isn't really about more speed, it's about more effiecent, smooth driving. More gears, provided they were shifting at the right times would be great for low speed driving, and getting to 100k's.