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Toyota Prius - Traction Control vs Vehicle Stability Control

I am finalizing on the Prius and wanted to know whether one should invest the money for Vehicle Stability Control. As in 2007 Prius, it already comes standard with Traction Control.
Any thoughts/experience would be appreicated.
Any thoughts/experience would be appreicated.
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Put another way, the TC is the system some owners wish the car didn't have, and VSC is the system some owners attribute to saving their lives.
I haven't heard anyone complaining about high elevations. There are a few owners in Colorado reporting that they do fine. Except in 2 or more ft. of snow, but that's to be expected.
Toyota had to set the traction control to very high sensitivity to protect MG2 (motor generator 2 - the one that moves the vehicle most of the time). If you spin the wheels on ice you could over-spin MG2 and destroy it, so TC protects it. Perhaps a little too aggressively. So far every posting of problems I've read has been on a low speed hill such as a driveway.
So if you know you will experience snow or slippery conditions on hills, good snow and ice tires are a "really good idea" (tm).
If you're wondering why it over-spins MG2, it's due to the design of the HSD. The rotation speed of the ICE (internal combustion engine), MG2, and wheels depends on the speed of the other two devices. If the engine is off or idling and you spin up the wheels you also spin up MG2 (a lot). This is also why you can't have the engine off above 43 MPH - it will over-spin MG2. There is a good visual example of this on Priuschat you can mess with written in flash, I think.
http://www.safercar.gov/pages/ESC-EquippedVehicles-2007.html
I do use snow tires on the Prius but not on the Outback.
We always used the Outback when it's snowing or if we're going on a trip and snow was forecast.
We just replaced the second and last Outback with a Hybrid Highlander and will hens forth use that whenever snow threatens. The rest of the time we use the Prius for short and long trips and the Highlander only around town if the Prius is already being used. (I think the Highlander was a mistake but we need a least one 4WD)
I think the HH uses electric motors on the rear wheels, and that will not do for heavy useage (the motors overheat and simply stop working until they cool). However, for basic "occasional" AWD use it will drive those wheels.
This has been reported as being fixed by a change to the CU software, allowing the wheels to spin a little bit.
If a Prius is Parked with Both left side wheels on asphalt/concrete, both right side wheels on ice or snow or gravel, and then the Driver then decides to accelerate....
What happens?
1. Prius goes nowhere (wheel spins, traction control cuts power)
2. prius spins wheels on right side and tries to move
3. Prius simply moves forward without problem
3 is how the new Subarus I drove handle the situation. Huge traction advantage in winter, but the Subies guzzle gas by comparison.
Comments? Is braking also an issue under those conditions?
With braking, it's no different than any other car. Even a Subaru will have trouble stopping on ice. It all depends on what tires you have on the car.
In reading this topic (posts before yours) I see people are still confusing traction control, anti-lock braking, and VSC.
Traction control will reduce or cut power to the wheels when you accelerate, if the wheels spin up. In the case of the Prius, it does this aggressively to prevent over spinning of one of the motor-generators (wheels can spin up faster than the engine can start up - if the engine is not running motor-generator #1 can be over spun if the wheels go faster than about 43 MPH or 66 kmph.) I have noticed this is less of a problem if the engine is running, so it looks like the computer allows for this condition.
Anti-lock braking will vary braking power on each wheel if the wheel spin rate of that wheel is a certain percentage lower than the other wheels. Some are three channel (both rear wheels are considered one) and some are four channel (all four wheels are individually controlled). This system only works under braking. The Prius uses regenerative braking, as well as hydraulic braking. The regen braking is very effective in slippery conditions, as it is not as forceful as hydraulic braking. The big benefit with anti-lock braking is it allows you to steer around whatever you might be traveling toward, whereas if you just lock the brakes you cannot steer (car continues in the direction it was traveling until it stops or hits something).
VSC, or vehicle stability control, also called dynamic stability control, and several other names, will use braking on individual wheels to correct a skid and may also reduce power, usually even before the driver realizes there is a problem. This is usually not under braking, but driving through a corner. It can also work while braking, in concert with anti-lock braking above.
Silver Spring, MD
I recently purchased a set of standard 15" Prius rims on eBay, and just had mounted four "performance" snow tires, not as aggressive as some out there in terms of deep snow capability, but better in terms of dry road handling and somewhat higher winter temps, the sort we have here in mid Maryland, other than the 2 and 3 foot snows we've had in the past.
I purchased Hankook icebear W300s. Another tire that rated highly in the categories I was interested in, but not available at the retail level in this part of the country, was the Viking Snow Tech.
Today's snow looks to be about 3 inches out here. I'll know when I leave work how it does on the standard Touring tires, unless the roads are cleared by then. Last February, just after buying the car, I did take it through the neighborhood on the unplowed street, about 3 inches, and had no trouble at all, on level ground.
I know I will have to put up with the yellow TPM warning light while I have the snows mounted. And I also now understand that after I put the originals back on, I still might have to take it to a Toyota dealer to have the sensors re-registered.....I hope not.
I got 185/65R15 88H. They are not cheap tires, so be prepared to pay around $100 each for them (best price I was able to fine on the internet).
Just to complicate our lives, Nokian have come out with a new version WR, the WR G2. It looks even better on paper. It's lighter yet stronger (higher load/speed rating). It hasn't been out long enough to get peoples experience yet. A fellow over on Priuschat may purchase them to try them out. He was quoted $103 each from a local tire shop. Not a bad price.
I remember when we bought the car they had us sign something about using chains. Are the cables, like Super Z6 O.K. to use?
The roads up there have signs that say chains are required, which I assume is in effect during snow and icy conditions.
Celeste Kennedy
Driving our '07 on slick roads for the first time at the beginning of winter felt pretty skittery. After some reaearch, we got Les Schwab "Observe" snow tires. They aren't studded but are supposed to act like studded and are relatively quiet. (Les Schwab is a western US dealer).
In practice stops and cornering on very icy roads, they are confidence-inspiring. Also, no problem on mountain passes as long as the snow's not too deep.
Putting on snow tires cost 4-5 mpg, but easily worth it because the car feels more like a Subie with studs (my previous winter car).
Our driveway is 3/4 mile long, steep, with a couple of tight turns. With the factory tires, my '07 Prius lost traction in 1" of wet, new snow. With snow tires, it climbs quite well. Like any car, when it starts to slip, backing off very slightly helps to get the grip back.
YMMV, but I've found the biggest problem with slick stuff (snow, rain or gravel) is that the Prius has a lot of torque and the traction control system doesn't manage it well if you just stomp on the gas.
Use TRAC as an indication of conditions, not as something to rely on as help in those conditions, its actions are far to ROUGH-EDGED.
I also have a GMC Sierra 2500HD Duramax Diesel 4x4 with locking differentials. Now that's what you want to be in in the snow. I want my wife to drive the truck all winter, but she won't do it unless the weather is really bad because she says it too big and too hard to park, so she's frequently in the prius, which scares me. Saving a few extra bucks on fuel just isn't worth it.
I'll have to sell it if Toyota doesn't come out with some new programming for the TRAC before next winter. It's a great little car in every other way, but this is just too dangerous. It makes no difference whether you stomp on it or gently feather it, or anything else in between, believe me, I've tried and the bottom line is it just doesn't go like it should. It's scary.
My friend has a Highlander Hybrid 4x4 and gets around just great in the snow. I wonder how the Camry Hybrid does? Is it just the Prius's that are so badly engineered? Does anyone know how the Civic Hybrid does?
Traction on ice or well packed snow requires a huge tread contact CSA and WEIGHT...!
The Prius has neither...!!
I wouldn't drive a Prius in adverse roadbed conditions, and if I was forced to, not without tire chains.
And yes, I know, very well, tire chains on only the front of a FWD vehicle can turn hazardous instantly. So drive slow, VERY slow.
On a side note, this can be an issue with any type of car. Some traction controls interfere more than others. We had a rental vehicle, on vacation one time, and that Buick flat out stopped and wouldn't even put any power to the wheels with the slightest amount of wheel spin on snow and ice.
As always, tire selection and driving technique make the biggest different, but and overly-aggressive traction control system can be a real pain. Some amount of wheel spin allowance can be a good thing in many situations. I regularly turn off the traction control on my wifes car (rear wheel drive and manual tranny) in snowy conditions. That being said, simply putting a couple bags of sand over the rear axle made a huge difference. Not an option with a front wheel drive, but the engine is already weighting the drive axle (the main reason front wheel drives have a traction advantage in snow).
The stock tires on the Prius are built for mileage, not traction/permorance. Moving to a snow tire (such as Blizzak) would resolve winter traction issues in all but the most extreme situations. If one isn't willing to go to a dedicated snow tire (and the associated second set of wheels and the twice-yearly swaps), find a good all-season with the best snow rating you can find. That, too, will make a huge difference over the stock tires and completely change the personality of the car in those conditions, plus you don't have to swap them in the summertime.
And remember that those electric motors have absolutely "stellar" low end, low speed, TORQUE. Perhaps you need a "snow" mode.
I love my Prius, but when a blizzard is on, I'm going to be driving my GMC Sierra 2500HD 4x4 Duramax Diesel and while I'm doing it I may even stop to pull out some of the stuck Prius's.
I did have one issue with the traction control, but it was in a situation that I didn't entirely expect to make it through anyway. Climbing a rather steep hill, I got half way up when traction became such an issue that the power cut out completely leaving me sliding backwards a bit. I think I might have had a chance without traction control, but I can't say for sure. Anyway, I was able to back up the rest of the hill without a problem.
It definitely does prevent much wheel spin. For a better description, when the wheels spin, the power gets cut until the spinning stops. At that point, if you are too aggressive, you can quickly spin them a bit more and again the power cuts out. I think it completely cut out when I started sliding backwards. This might be a bug in the software, and this could have been more dangerous if I had been somewhere where I could have had someone behind me.
So I guess, overall, I think tires probably make the biggest difference. Maybe they're just telling drivers that they need different tires if they're driving in snow.
So, I agree, Prius is awful in even light snow in my experience. Now, did I play and practice with it? Not much. And those were probably the stock tires (though I can't recall). We have good Michelyn all seasons on there now just to help with rain, etc. We both work below snowline, so full snow tires on the Prius are not an option (our other cars are a Subaru Outback with triple treds and my Tacoma with 31 BFG's...both work great in the snow, though the Goodyears begin to lose their snow mojo a bit around 40K...with two bags of solid concrete in the pickup bed I am fine).
Up here, as those of you in snow country know, trying to get to work in the pre dawn dark, or get home, good tires in good condition and all the right AWD or FWD are not a luxury of living, they're part of staying alive. Would we have bought the Prius knowing this? Probably. (The salesguy swore the traction control would make our Prius as good in the snow as an AWD).
And no, I have no interest at all in UAW or any of that; I teach for a living.
My Prius is sitting in my driveway now, packed snow and ice are on the road, and we're going on a long car trip (1000M) in two days; a storm is coming in tonight; do I dare to try and drive it out before? Not likely, but if I do, I'll let all know how the Michelyns worked. Worst case, AAA can tow me down to dry pavement if nobody smacks me while I'm sitting there.
My sincere thanks for the many helpful comments on this board. I haven't heard of the software retrofit, but if it didn't cost a fortune we'd do it.
I have Blizzak WS-50's on my 2004. They were OK the first winter but are not good now.
I did use them for 4 winters (off in the spring) but want to replace them with something better.
The Prius does not give you the traction of four wheel drive and you should probably put chains on in severe conditions. If I had the option of driving a 4x4 Duramax in really bad weather, I would. (Sadly I don't) However, I am very impressed with the VSC system. Having experienced midwest and east coast winters all my life, I think this system makes you look good. For example, I am used to building up some speed to make turns with heavy snow buildup. In my older cars, this maneuver would give me some serious "fishtailing". This is essentially eliminated with the Prius. This is without a doubt, the best car I have ever owned for snow driving. (Previous contenders SAAB 900(92-98), VW GTI(99-07))
But even in the middle of summer in dry weather, the traction control freaks out. I'll be driving through downtown Boston traffic and get the slip light just by driving over a manhole.
Is there anything that the dealer can do to ratchet down the traction control?
I was sliding around a lot this week so yesterday I replaced my 4 season old
Blizzaks WS-50's with WS-60's. Too soon to tell if that will help.
Try the Nokian WRG2 it's a 50,000 mile snowflake rated tire. They work awesome!
If you need a full blown snow tire Nokian makes those as well. I've bought a lot of snow tires over the years, but nothing beats Nokian tires in the snow and ice.
Once you go Nokian, you will never go back! :shades:
Like everything else with the vehicle it takes some relearning; e.g. putting the pedal to the floor is the last thing you want to do.
To answer your last question, NO. The TC technology is put into the hybrids due to the huge amount of torque from the e-motor. It has to be present at all times or else you'd just be sitting at a stop sign in dry weather spinning your wheels like at a funny car drag race.