Car Talk — Continuously variable transmissions may seem weird at first but help boost fuel economy
•Q. I’m considering getting a new Honda Accord four-cylinder. For 2013, Honda went to a CV transmission, replacing the five-speed automatic. I wonder about (1) the longevity of this type of transmission; (2) the effect on fuel economy; and (3) the overall driving experience for someone (me) who has driven both manuals and automatics for 50 years. Your carefully considered opinion is appreciated.
TOM: Hm. Would you settle for one of our usual opinions, which are ill-considered and half-baked?•
RAY: I think it’s fine for you to get the CVT. We’re living in a period of rapid gear inflation. For a long time, we had three-speed transmissions. Then came four-, five- and, pretty quickly, six-speed automatics. Then, in just the past couple of years, we started seeing seven- and eight-speeds, and now we hear about companies working on nine- and 10-speed gearboxes.
TOM: The reason to add gears is that, generally speaking, the more gears you have, the better your fuel economy. The more you can match the demands of your driving to the most efficient gear ratio for those demands, the less fuel you waste.
RAY: A CVT (continuously variable transmission) is a gearbox with infinitely variable ratios. Actually, no gears at all — just belts that move constantly up and down two cone-shaped pulley-thingies to adjust the gear ratios.
TOM: It’s definitely a plus for fuel economy. That’s why Honda has started using it.
RAY: In terms of longevity, we don’t really know. Some of the early CVTs had trouble with high-torque engines. But Nissan and other companies have been using them successfully for years now, and, so far, there don’t seem to be any particular problems.
TOM: The driving experience is a little different. Under most normal, gentle driving conditions, you probably won’t even notice it. Good transmissions are so smooth these days that you barely feel the shifts now anyway. But when you really need to accelerate, you will see a difference in the way the transmission and engine interact with each other.
RAY: If you stomp on the gas, like when you’re on a highway on-ramp, you’ll notice that the engine revs way up at first, to give you immediate power. And then, as the car picks up speed, the engine actually goes slower and slower as the transmission continues to adjust the gear ratios as the car needs less power.
TOM: It’s a little odd at first, but so was trying to work with my brother, and I got used to it.
RAY: It’s certainly not a reason to avoid the car. And while there’s no guarantee, Honda, overall, has a pretty good track record for durability and reliability.
TOM: I’d suggest that you go and test-drive one. You’ll see what we’re talking about. Make sure you include some sort of sudden, harder acceleration in your test drive so you can experience the primary difference we’re talking about.
RAY: But remember, every new technology is a little weird at first. When the first automatic transmissions came out, it was weird not to shift the gears yourself. When the first anti-lock brakes came out, it was weird not to pump the pedal in a panic stop. And when the first iPhone came out, it was weird to be able to have such a cool phone and still not hear what the other person was saying.
•Q. To use the emergency brake or not — that is the question! We bought a Mazda3 with a manual transmission for our son, and the question is whether he should engage the emergency brake when he parks his car. He leaves the car in gear but does not engage the emergency brake when he parks. He knows that if he were to park on a hill, he could engage the emergency brake for additional security (we’ve also talked to him about turning his wheels depending on if he is facing downhill or uphill). The question is: Should he just simply engage the emergency brake all the time — make it a habit? His father thinks one way, his mother thinks the other. What do you all say regarding the best practice to teach our son?•
RAY: He should make using the parking brake a regular habit.
TOM: With an automatic transmission, using the parking brake is not as crucial, because putting an automatic transmission in park actually locks at least two of the car’s drive wheels. But if you’re driving a car with a manual transmission, there’s not much between staying parked and rolling down Pike’s Peak.
RAY: Putting the manual transmission in gear doesn’t “lock” anything; it makes the car harder to move, because you have to overcome the resistance of the engine, but it’s hardly impossible to move a manual-transmission car that’s in gear. And if the clutch is worn out, or your engine compression is low, it’s that much easier for the car to roll.
TOM: It also can be knocked out of gear in a way an automatic transmission can’t. If you’re putting packages in the car, or if the dog jumps in first, it’s possible to knock the shifter out of gear and send the car a-rollin’.
RAY: So, for those reasons, we recommend that everyone with a manual transmission make a habit of applying the parking brake every time they park the car.
TOM: The reason you want to use it every time is twofold: One reason is to simply get in the habit so you remember to apply it — and, just as importantly, remember to release it whenever you drive away.
RAY: Second, when a parking brake isn’t used regularly — particularly in climates where rust is an issue — the cables, which run under the car, can corrode and get stuck in place. Then one of two things happens: Either you can’t use the brake when you need to, or you snap the cables trying.
TOM: So tell your son it’s just another one of those good habits to get into. Floss your teeth, call your mother once a week and use your parking brake.
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