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Toyota Prius, Hybrid Cars, Hatchback, Sedan
#15 of 54 More on traction control
Nov 25, 2007 (9:10 am)
Glad this topic is here as traction control is a big issue in my decision on the next car (I live in Portland OR and we are expected to have a lot of snow and ice this year).
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....
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?
#16 of 54 Re: More on traction control [kurtamaxxxguy]
Nov 26, 2007 (9:00 am)
What happens depends on what traction is available. If you are going to rely on the tires that come with the Prius you will have problems. If you put -real- winter tires on the car it will go (I use Nokian WR tires). It may spin, wait, spin, wait, then go, if it's slippery enough. If you are on level ground there is really not much of a problem. Basically, it's pretty much like any other front wheel drive car. The only difference is the traction control is a bit more sensitive.
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.
#17 of 54 Re: traction control and snow tires
Dec 05, 2007 (10:48 am)
My 2008 Prius slips even on flat roads in minor snow (less then half-inch). I assume I need to purchase snow tires (and new wheels). Are the Nokian WR tires suitable for the 2008 model? Is there research on the range of appropriate snow tires for the 2008 Prius? (not Touring edition) Many thanks -
Silver Spring, MD
#18 of 54 Re: traction control and snow tires [elissacl]
Dec 05, 2007 (11:16 am)
I have a 2007 Touring edition.
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.
#19 of 54 Re: traction control and snow tires [elissacl]
Dec 05, 2007 (12:08 pm)
The Nokian WR works well on the 2007 and 2008 Prius. There are two available in the stock size - I got the higher speed/load rated one. If you get Nokian WRs you don't need to take them off for summer. They are true all-season tires but have the snowflake symbol on the sidewall so you don't need to "chain up" on interstates when that situation presents itself. This is why I got them. No need for extra wheels/changing wheels/tires as the seasons change.
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.
#20 of 54 Chains for '06 Prius?
Dec 06, 2007 (8:57 am)
We live in San Diego, CA and have a place in the mountains. Snow tires would not be practical. Any suggestions for chains or cables?
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.
#21 of 54 Re: Chains for '06 Prius? [pupvolunteer]
Dec 06, 2007 (7:26 pm)
http://www.spikes-spiders.com/ has the answer for low clearance Prius tires- a bit pricey and not for high speed or even a short stretch of bare pavement ... but on/off in about ten secs per tire with a little practice and once the hub-mounted assy is properly installed on the front(drive) wheels... must be removed for rotating tires is the only drawback I've found.
#22 of 54 Re: Snowy hills [lalcott]
Dec 26, 2007 (3:37 pm)
Good snow or all-season tires make a huge difference. Also, throttle control is important.
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.
#23 of 54 Re: Snowy hills [methowvalley]
Jan 17, 2008 (12:34 pm)
We have a 2006 Prius with the GY (#1) package. It is very dangerous to drive in snow, which we have a lot of in Wisconsin because it cuts power to the wheels as soon as any slippage is encountered. That may be ok in the rain, but when driving in several inches of snow, there is ALWAYS slippage. Our old Chevy Cavalier gets around in the snow just fine. You just get on the gas and those front wheels just start chewing their way through the snow. In the same scenario with the Prius, you get on the gas and it dies leaving you helplessly waiting for someone to slam into you and kill you. It is not a fit car to drive in snow. If no one has been killed yet, they will be. This is VERY dangerous. BTW - Toyota says that's how it is supposed to work and refuses to do anything about it. They're going to regret that when the lawsuits start. Deliberately engineering such a dangerous design makes them fully culpable. It's inexcusable.
#24 of 54 Re: Snowy hills [andyu]
Jan 19, 2008 (12:26 pm)
The secret to driving ANY car on the slippery stuff, especially FWD it seems, is learning to feather the throttle YOURSELF just up the point of losing roadbed traction and not beyond. Once TRAC kicks in it will not nearly have the finesse you could use were you to bother to take the time to learn.
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.