When it comes to gears, how many is too many?
We spill the beans on Lexus’s 10-speed ’box
THE WORLD’S car makers are often sheep-like in their adoption of vehicular fashions. However, they – and transmission manufacturers – certainly aren’t aligned on the best way to transmit power.
With the traditional manual on the wane, the jerky robotised manual, potentially unreliable dual-clutch auto, boring CVT and even the humble torque converter auto have all been offered as the transmissions of the future.
And it’s the latter that Lexus is set to adopt for its forthcoming LC 500, which is due next year. The grand touring coupe, which is based on the LF-LC concept car shown at Detroit in 2012, will feature a 10-speed auto.
It joins the likes of the 2017 Ford F150 Raptor and 2016 Chevrolet Camaro ZL1 in having 10 ratios.
The underlying aim of the new gearbox is fuel economy, though the marketing benefits of a 10-speed can’t be overlooked.
But will it bring a performance benefit and, if so, how? Well, if you can keep an engine in the meat of its torque band, you’ll maximise the car’s acceleration. It’s this simple principle that spawned the closeratio racing gearbox back when 'boxes only had four or so slots.
Closely stacked cogs stop the revs from dropping off, which is particularly helpful for highly strung engines that make their power high in the rev range. On the other hand, there’s the time lost doing all those gear changes – the Lexus would do several in the sprint from 0-100km/h.
More importantly, in terms of driver appeal, will the boxset of 10 go down as a motoring ‘best-of’ or pale alongside the classic opengated manual?
Well, the experience of riding a big whack of torque, using just one of two ratios, is one of the most delicious elements of piloting a bigengined, tall-geared car on a tight and twisty road. Think Commodore SS on a favoured slice of mountain tarmac, blasting from corner exit to entry in second and third…
The 10-speed experience could be a mega-miser, its progress punctuated by a road-train-like constant swapping of cogs – or, the changes will be so smooth it’ll just feel like a CVT (without the wideopen-throttle drone).
If the manual is dead and multiratio 'boxes waste time shifting gears, surely the CVT is set to rise? In theory, it could, however the
"Lexus's LC 500 joins the F150 Raptor and Camaro ZL1 in having 10 ratios"
CVT is not naturally a high-torque device, and anyone who has driven one knows why even the biggest CVT proponents are now giving their gearboxes artificial ratio steps to mimic a conventional auto.
While having a continuously variable gear ratio beats, well, pick any number between seven and 10 ratios (in the spec-sheet contest, at least) an elastic throttle and droning power delivery has no home in the hi-po car.
Time will tell whether the 10-speed slusher does.