Why adding extra gears to transmissions isn’t always a good idea

“Less is more”.


It’s a saying I’ve generally disagreed with up until now. I like more.

More food.

More beer.

More fun.

More power.

But I’ve recently come to the conclusion there’s an exception the idea that more is better, and it centres around gearboxes. Specifically, the number of gears on offer in some automatic transmissions.

I’ve spent plenty of time in automatic cars (about 600 hours per year over the past four years, by my calculation). As such, I know what I like.

There are some minimalist four-speed automatics that do the job nicely, such as the Peugeot 2008's. The Honda CR-V has a pretty decent five-speed auto, too. Then there are excellent six-speed torque converter automatic transmissions, such as the Skyactiv self-shifters seen in the Mazda range.

The seven-speed dual-clutch ‘boxes employed by Audi and Volkswagen – despite their apparent longevity issues - appear to have their low speed issues sorted, with the septicognal (that’s a word I’ve just decided exists) Porsche Doppelkupplungsgetriebe (PDK) in the Porsche Cayman, Boxster and 911 could just be the best gearbox ever.

The brilliant eight-speed automatic from ZF that is fitted to cars such as the Porsche Cayenne, Volkswagen Touareg, Range Rover and the mind-blowing Audi RS6 and RS7 deserve mention for their ‘smooth operator’ status.

But nine gears – that just seems a bit much.

I recently spent time driving the new Jeep Cherokee, an SUV with a transversely mounted nine-speed automatic transmission that could be the worst auto I’ve used this year. Oh, apart from the Fiat Abarth 500C’s five-speed automated manual. Yuck.

Anyway, back to the Jeep.

The idea of nine gears is, by Jeep’s own admission, a means of helping the car use less fuel - the company that produces the gearbox, ZF, claims it can save up to 16 per cent over a six-speeder. The brand could have made the vehicle lighter; could have smartened up their engine tech with downsizing and turbocharging. But instead of removing, Jeep kept it American and decided more was indeed more.

Jeep is not the only brand to employ this newly developed cog-swapper. Range Rover added the ‘box to some variants of the Evoque line-up earlier this year.

Some of my esteemed colleagues have suggested that the car offers better value because its automatic gearbox has nine cogs. Like getting more gears than competitor SUVs is some sort of bonus.

But it’s not a bonus. Not by my calculations. More airbags, more cupholders, more stereo speakers, more seats – these are things that people pay more for. Not cogs in a case.

Over identical roads and in situations as closely replicated as possible, the Jeep’s nine-speed gearbox fell well and truly short of the sort of cleverness, precision, smooth action and drivability of its very close rival, the Mazda CX-5. I even caught the snoozy nine-speeder sluggishly fumbling to take off from a standstill at more than one intersection.

I noticed heavy, thumping shift-shock under heavy acceleration (seemingly exacerbated by cold morning starts), clumsy cog swaps when the right pedal was under less duress, and daft fuel consumption due to the vehicle’s electronics only allowing ninth gear to be engaged in D when the speed exceeds 130km/h (maybe its further fuel for a case to raise speed limits in Australia - but that’s another topic entirely…).

Don’t get me wrong, I’m all for technological innovation. And anything that will potentially lessen a car or brand’s carbon emissions – not to mention the strain on the buyer’s hip pocket – is worthy of investigation and eventual implementation. I’m just not sure the investigation lasted long enough in this case – and nor was Fiat Chrysler Automobiles, as the company updated the software twice before the car arrived on sale locally due to rough and delayed shifts. Perhaps good things come in threes…

Transmission experts such as ZF Asia Pacific manager Josephn McCorry has told CarAdvice in the past that nine gears is “the limit of efficiency”.

“From an engineering point of view, if we’re looking at speeds, going from a four-speed and then a six-speed is the ultimate and then an eight-speed and now a nine-speed, what we start to get to is efficiency maximum,” McCorry said.

He suggested any more than nine cogs could be too many. But 10-speed automatics – as are being worked on collaboratively by General Motors and Ford – could be pushing the limits, even for McCorry.

“Could you go to a 10-speed? Maybe. But then it’s [a question of] what is the cost benefit? And I hate to say there’ll never be a 10-speed because people when there was a six-speed said well, will there ever really be an eight- or a nine-speed?”

As with most groundbreaking technologies, there will undoubtedly be some fine-tuning, but my experience so far has lead me to the conclusion that the nine-speed automatic is a gimmick.

Heck, I’m even OK with infinite ratio ‘boxes, such as the CVTs used by Nissan and even the whooshy new Subaru WRX auto.

But for now, I say ‘nein’ to nine gears.

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