Believe it or not, it was Leonardo da Vinci who sketched his version of a stepless Continuously Variable Transmission (CVT) back in the 15th century. Fast forward a few hundred years to the 1950s, and it was DAF, a small Dutch car manufacturer which mass produced a car with a CVT, designed to appeal to first time drivers with qualms about shifting.
But what about now? Should you buy a car with a CVT? Does your car have a CVT? Or maybe you’re now wondering ‘What is a CVT?’
A Continuously Variable Transmission (CVT) is essentially a single speed type transmission designed to be able to deliver a smooth driving experience and improve fuel efficiency. Its design allows the vehicle’s engine to run at its most efficient revolutions per minute (RPM) for a range of vehicle speeds.
Earlier CVTs can sometimes feel awful, almost like a rubber band stretching and confuse drivers that there’s something wrong with their car. When you step hard on the accelerator, the engine races as it would with a slipping clutch or a failing automatic transmission. Fear not, this is normal - the CVT is adjusting the engine speed to provide optimal power for acceleration.
It’s a bit like going out in a boat with a small outboard engine, you rev the outboard and the revs stay the same while the boat gathers speed. You also don’t get that immediacy of throttle control if you increase or decrease the revs, and that can sometimes be unpopular with drivers. In short, not everybody likes the CVT experience, well initially at least, because it jars horribly with everything they’re used to.
Manufacturers sidestepped the problem by artificially creating ‘gears’ in their CVTs. Put simply, these are pre-set points where the designers decide that the two pulleys will be of certain relative sizes, just like normal gears.They then set the CVT to fix those pulley sizes, and when the engine runs out of revs it ‘changes gear’ to the next set of relative pulley sizes. This is the same thing a conventional transmission does, but instead of changing the ratio in stages by shifting gears, the CVT continuously varies the ratio, hence its name.
Another past downside to the CVT was the fact that there was no towing with one, they simply weren’t strong enough. This is gradually changing with the tow ratings of some vehicles reaching 2000kg. Manufacturers are now combining CVTs with turbocharged power plants, making a perfect combination. It now takes what was a high-revving screamer of an engine and gives it a boost.
Servicing is the key with these transmissions. Not all CVT fluids are compatible with every transmission, so we recommend checking with an expert on service requirements and intervals. Yes, it might cost you a few hundred dollars now, but that’s a lot better than a few thousand (minimum) later on.
If you’re buying a new car today, don’t be afraid of a CVT as they’re no longer the problem they used to be. Vehicle manufacturers around the world have spent considerable sums on R&D over the years transforming this technology from somewhat troublesome to extremely reliable.