2024 Prius with or without AWD?

Worth it if it keeps you out of the ditch

 

We have both versions....front-wheel drive (2017) and AWD (2021). I've tested my AWD and I was very impressed...especially on icy roads. The computer is quick to turn on the rear wheels when the front start slipping.

 

Maintenance is almost nothing. It's a very simple and reliable system. A motor/generator is attached to a fairly simple differential gear. If you want to err on the side of caution, you just replace the fluid in the differential around every 80k miles at the same time you do the main transaxle. It's likely the original fluid would last for almost 200k miles, but changing it every 70k-90k miles is the difference between a unit that lasts 200k and one that lasts 400k+. You also need your mechanic to keep an eye on the rear axle boots for damage just like on the front axles.

The big thing to consider is the fuel cost over the FWD. You're going to lose about 3mpg. I think you said in another post that your average yearly milage is around 8k/year, but that it's likely to drop a lot in a year or two. At around 8k miles in a northern climate, you're looking at something like 15 extra gallons of gas over the course of a year(probably less, but I'm being conservative). That's around $50/year in your neck of the woods. If your yearly milage drops after your retirement, so would that dollar figure.

I also had a FWD Prius for many years in a northern climate and had few problems as long as I had a set of good tires(I went with Nokian WRG3/4 all-weathers). I've now had a gen5 AWD for one full winter. I really wish I could give a good comparison, but we just had one of the mildest winters in history and I had almost no chance to test the car. We had a couple bad days in late 2023 that showed me the stock Toyo tires were crap on snow and ice. I was able to get a set of Michelin X-Ice Snows in the 19" OEM size just after the new year, but we've had almost no real snow or ice since then.

The only testing I was able to do was a morning after we received a night of mist/drizzle on frozen roads. For a few hours, the roads had a perfect glass coating of ice. The combination of the winter tires, AWD, and traction control allowed me to keep the car perfectly in control even when I floored it and forced the wheels to start spinning. In previous cars, I would have felt the car start to slide in at least some direction, but the AWD kept everything straight. I wish I could've done additional testing, but we just didn't get enough bad weather this year.

 

Gonna get confusing?

 

Well, comparing the MPG between my wife's 2017 and my 2021 and it's not even close...the 2021 gets 5-8 mpg MORE. Why? I don't know but suspect it's the batteries. She has the Nickel-Metal Hydride and I have the Lithium-Ion. Odd because my car weighs 200 pounds more. (Maybe newer batteries and newer computers??)

 

Get AWD. It's worth it.

 

Better to have it and not need it than need it and not have it.

 

AWD is never strictly necessary, but if you can afford it, it is always better to have than not have.

I love my AWD matrix, but the prius prime doesn't have an AWD option so we were stuck with FWD. AWD wasn't, in and of itself, enough of a reason to forego the prime. But if there *was* an AWD prime we'd have optioned for it.

If money is a factor though, honestly, good winter tires (which you should always have anyway) and being a quality driver is sufficient for 99% of scenarios. AWD can't overcome poor tires nor poor driving skills in the snow. Remember, it helps you get going, it doesn't help you stop.

A big thing to remember is that its not just initial cost, or the maintenance of changing fluid once or twice in your ownership period. But if you lose a tire for whatever reason, you *have* to replace all 4 tires if any significant wear has taken place. You can't only change the tires on the same axle, with AWD, all 4 need to be changed together, every time.

 

That can be true on physically connected systems. Volvo had a delicate system that could suffer damage from uneven wear and I understand Subaru to have similar advice.

The Prius/Corolla/Sienna AWD-e system doesn't physically connect the front and rear wheels. It's a 40hp rear motor with just an electrical cord routed to the power source. It isn't obvious to me why this would have tire requirements that differ from a FWD car.

The interesting aspect to me is that the addition of a 40hp rear motor doesn't increase peak hp by 40. As I understand the system, it is limited by the amount of electricity it draws overall. This should mean that as the rear motor draws current and makes power at low speeds (up to 50 something mph), it provides about that much less power to the front wheels.

If that's true, it might handle differently in some situations. Entering a rotary in wet weather means not overloading the front tires with too much torque while also turning. Reduced front torque in that circumstance could be a real handling benefit.

 

I think the reason you change all your tires isn't *just* for mechanical reasons. Uneven tire wear is bad for handling in general, and when you are giving varying levels of power to all 4 wheels, one set having significantly more traction than the others due to their tread wear is probably not great and may confuse the traction control system too. Granted, I'd also generally want similar tire wear/tread depth on every tire on a FWD or RWD also for my own peace of mind.

Granted, if they're 6 months old and have basically no wear, I wouldn't be worried about changing all tires. But if they had half their life behind them, I'd just swap em all and sell the good tires as used for people who might need spares or just a single pair who don't have the finances to do all 4.

 

My opinion after driving my FWD in massive snow, with factory tires pumped way too high, is that AWD is not necessary.

I sure do enjoy the FWD fuel economy.

 

The difference in wear between the new and worn tires can cause issues and error codes in an AWD system regardless of the system type.

 

We finally got some rain and I was able to get in some wet weather testing.

We've all had the FWD experience of carrying speed into a turn, applying throttle and having the front end plow. I tried some speed through low speed turns with lots of throttle. Rather than front end plow, I got both the front and back intermittently breaking free (thanks to the awful Toyo Extensas) but the car rotating through in a neutral way.

The power distribution display shows most of the electric power allotted to the rear at higher speeds, 40 to 60mph, and lighter throttle.

 

Were you seeing the VSC helping out?

 

I had to look that up. It reads like a brake substitute for a LSD.

The answer is "maybe". The front and back would alternately slide but then snap back into line quickly.

I had read that the system would send more power to the outside rear wheel in a turn, but that didn't make sense to me with a rear open differential. The power distribution display always shows both sides equally in normal driving. I couldn't see the display in testing because I had traction control off.

"VSC" would be consistent with what I observed.

 

Yes, that sounds like VSC. A light could turn on when it activates, but that can be missed. It doesn't get turned off with traction control. In most cars, you have to hold the traction control button down to turn it off.

The wheels get the same amount of torque. Torque multiplied by rpm is the power. The outside wheel is spinning faster, so more power. With open differentials, you can't direct power to an individual wheel.

I don't see Toyota bothering with a display to show level of output to individual wheels. Then VSC works through application of individual brakes. It might reduce power, but that is more a tool for traction control. The two usually work together. I'm not sure how having traction control off effects VSC operation.

 

I'm not asserting that the info is accurate, but one of the Toyota vids I saw asserted that at higher speeds the outside rear wheel gets more power to assist the turning motion of the car. That could just mean that the inside wheel gets a little bit of braking with the result that the torque necessarily goes to the outboard wheel. Toyota also described the fore/aft power split of the Corolla GR as a power distribution, but it's a result of the tension cause by different wheel speeds, not a direct distribution of drive energy. -- a result rather than a cause.

I'll try to disable VSC for snow testing.

 

Using brakes like that is torque vectoring.

On accumulated snow with the Sonic, I turned off traction control to allow the wheels to spin, but left VSC on so I wouldn't slide off the road.