Dear Car Talk:
You’ve got the most fun column in the paper.
In 2014, I bought a new Toyota Camry XLE Hybrid. It’s the best car I’ve ever owned. It’s got about 72,000 miles on it. Everything is working great. But the 10-year warranty on the “big” hybrid battery will expire next year.
Replacing that battery costs between $3,000 and $5,000 at a shop. Is this a DIY job? If not, do I wait until the battery “dies” or just bite the bullet and replace it now before it wears out? Thank you.
— Eric
No, and no.
If you like the idea of 200 volts of electricity coursing through your most sensitive body parts, then, sure, Eric. Go ahead and replace the hybrid battery yourself.
On the plus side, you’ll also get a free, Bob Ross-style perm. Those battery packs are labeled “high-voltage” as a warning to people like us to not mess with them. So, I’d definitely let a well-trained shop handle the hybrid battery replacement.
The good news is that you may never need to have that battery replaced. Your battery warranty “only” runs for 10 years. But that doesn’t mean the battery won’t last longer than that. Sometimes much longer.
We’ve had more experience in the shop with Toyota Priuses than with Camry Hybrids, since they’ve been around a lot longer. But the hybrid systems are very similar.
We have some customers with 250,000 or more miles on their hybrid Priuses, and they’re still on the original battery. There are even some that are used as taxis, so they’ve arguably been subjected to the toughest stop-and-go conditions imaginable, and many of those have their original batteries, too. That doesn’t mean yours will necessarily last that long, but it could.
So, under no circumstances should you replace your hybrid battery proactively. It’d be like replacing a car’s gasoline engine at 72,000 miles just because the warranty was about to run out. That doesn’t make any economic sense, does it?
My advice is to start putting $10 a week in a jar. And by the time your battery fails, if it ever does, you’ll have the money to replace it. And if the battery never fails, you’ll have a down payment on your next Camry Hybrid.
Dear Car Talk:
Can you explain the physics and engineering for the concept of “un-sprung weight?” I see people who drive cars like mine (a 2006 BMW Z4) talking about how to “reduce un-sprung weight.” What are they looking to do?
Thanks.
— Russ
“Un-sprung weight” is an automotive engineering term. So don’t feel bad that you didn’t learn it in 6th grade vocabulary class, Russ, along with “egregious.”
In the simplest terms, “un-sprung” is everything below the car’s springs. So, it’s things like wheels, tires, axles, and brakes.
If you want to get picky, there is some weight that’s considered partially sprung weight. There are some suspension parts that attach both above and below the springs. But for the purposes of explaining the concept, think of it as mostly wheels and tires.
Why do people want to lose un-sprung weight? Well, aside from making your car look better in a bathing suit, people with performance cars want less un-sprung weight because it improves the car’s handling.
When you drive over bumps, the tires and wheels get bounced up in the air. The lighter they are, the quicker the springs can force them back down on to the pavement and keep them there. The more time the tires spend in full contact with the road, the better the car’s handling.
Heavier wheels and tires react more slowly, and when they hit the ground, they’re more likely to bounce up again. It’s more weight for the springs and shocks to manage.
This is not a perfect analogy, but imagine you were friends with my uncle Nunzio, and he gave you a pair of cement shoes. How maneuverable would you be? Not very, right? Your feet would be slow to pick up and move.
So, to reduce un-sprung weight, manufacturers (or car owners) replace steel wheels with lighter, aluminum alloy wheels. That’s probably the most cost-effective change you can make. And for people who drive on the streets (as opposed to the track), doing more than that is probably not worth the money.
Still, some zealots will look for narrower wheels that can be fitted with narrower, lighter tires. And they might even replace steel brake calipers with alloy calipers and use carbon ceramic rotors. You can go nuts with this stuff and even try to save a few ounces with lighter-weight lug nuts. But by then, your family will have left you, Russ.
