Here's what I do about braking issue...

First, that's not what "B" is for. You're actually fighting the hybrid system. It's for reducing speed from steep decents (like mountains), not routine stopping.

Second, you're tires are probably at the wear marks by this point. Slipping that much is an indication it's time for replacement. Also, that's likely contributing to the hydroplaning feel.
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Wow, that's wrong. It's not fighting the hybrid system. There is no mechanical difference between braking and using B. HOWEVER, it is a bad habit to use B all the time because it is much less safe - when you use B the brake light doesn't go on so can't serve as a warning to slow down to drivers behind you, and the braking is inconsistent because it depends significantly on the slope of the road. That is, B will work well to slow you down as you travel uphill, but won't do much to bring you to a slow and steady stop while going downhill.

But B does not damage the car. I just don't suggest doing it in traffic.


And BTW, you don't have a braking issue. It's all in your head. That is garbage the US gov't is telling you so you buy American cars.

 

Actually, there is a big difference between using B vs. leaving the shift selector in D and applying the brake.

When you shift into B, that is the logical equivalent of shifting into a lower gear. You will hear the gasoline engine rev up, and increased engine drag helps to slow the car down. That drag is not recovered as energy going into the traction battery.

When you apply the brake moderately while in D, most of the braking force is converted into electrical energy which charges the traction battery.

 

Then how come when I shift into B, blue arrows point to my battery.

 

I think you still get SOME regen from the motor-generator even in B, but engine braking is contributing a lot to the drag and deceleration. When I first got the car I tried it on one long downhill on the freeway, just to keep the car under 70 without using the brake pedal. It slowed it down to under 65 before I disengaged it and yes, MFD was indicating regen the whole time. Without it in B on that hill the speed will creep up to 75 before reaching bottom.

- D

 

Mary13, sounds like your tires are worn and/or underinflated. The Integrities on my 2006 still had plenty of tread. Haven't had much snow but the 2006 didn't have any problems in it.

 

Goodyear Integrity tires are basically crap. Even when brand new they don't have enough traction for snow. If you still have them at 25,000 miles it's no wonder you can't move.

Tom

 

My Prius was purchased in August 2009, so I don't have the new software upgrade for the braking ECU. This braking issue is not new to me as my old Corolla wagon ABS system used to do the same thing when ever I braked going over a plate in the road. I think the fact that the Prius is a bit shorter and narrower than a mid sized car creates a situation where the ABS system may be more prone to engaging than most people are used to. With a short car the chance of more than one wheel being on a poor traction surface, like a pothole or a plate in the road, at the same time is increased. Therefore the ABS is apt to engage more frequently. Honestly, I've noticed this less than with my old car. When I feel it, which is rare, I simply apply a little more brake pressure. I think some drivers are so used to the nice gentle slowing that one gets from the regenerative brakes, that when the ABS engages it feels a little weird.

With regards to snow traction, my Prius came with some very nice Yokahama all weather tires and the car has driven very well in the snow. I had been led to believe that snow driving could be a problem, and I guess it was when the car was equipped with low rolling resistance tires. We've had a lot of snow in the Boston area this winter and the Prius has performed surprisingly well. Once pulling out of my driveway on to a snow covered street the emergency avoidance light came on for about second. That was about it. The car kept moving and I drove to work. The only down side to driving in heavy wet snow is that it really lowers my mileage. The car can't exactly coast in that stuff.

 

Beware of putting it in "B" on snowy downhills. Last year when I still had my stock tires on, I approached a snow covered downhill one day. In the past I would put my car in a lower gear to give me engine braking. I thought putting the Prius in "B" would give that same affect. Well, 180 degrees later, wasn't quite what I expected luckily with all the snow, I was fine and no damage to the car. However, driving in reverse the rest of the way down was not my preferred method! I tried it again this past month, and sure enough, the tail started coming around.. but this time I was expecting it and put it back in "D" right away and no issues. My point is, the "B" doesn't act exactly like a lower gear in a non-hybrid vehicle.

And as for the whole braking "issue".. I've experienced the sudden release of perceived braking pressure. I just give it more break and it stops just fine.

I personally think it's the oil companies trying to give Hybrids a bad name so we can go back to buy their oil!!!

 

Good point. Shifting into B results in braking the front wheels, while the rear wheels don't have braking force applied. If your tires lose traction, then the car can go out of control as you experienced.

 

Is there any reason why you haven't had your tires checked for tread life prior to going in for a service visit? Any tire store can check them. For free. If you don't trust one tire store to give you an un-biased answer, go to a couple. There is always the dealer; you don't need to wait until the car needs servicing.

 

Yes, but with my other vehicles(20+), they did not react so aggressively. I think on a vehicle with a gas engine as the breaking force, the engine does not have as much braking force as the regenerative braking of the Prius?? Plus the transmission on other vehicles provided a power cushion between the wheels and engine? With the Prius, the regenerative braking is more aggressive? I'm not sure, but I know I won't try it again with stock tires! I did just recently purchase snow tire and wheel package and am hoping for lots of snow to go and play!!! :cheer2: I'll post back if it is different with more aggressive tires...

 

Regarding your 20+ other vehicles, for a fair comparison you would identify the subset with front wheel drive, and compare the driving characteristics of those vehicles vs. Prius.

In any event, the Prius could demonstrate more aggressive braking when in B. The Prius gasoline engine will exert braking force, plus regen braking is also happening, so you've got lots of braking on the front wheels while the rear wheels remain unbraked.

 

Agreed. My quick math in my head is 65% FWD, 30% RWD & 5% AWD. Also, I'm up to 27 vehicles in my head at the moment! I'm sure I missed one or two in there..LOL And pointing out the action of the Prius in that one specific condition is in no way saying it's a negative.. I love my Prius and it's one of the few vehicles I think I'll keep till she can no longer go. I'm experienced enough to know how to handle my car!! There are soooo many more dangerous situations people bring upon themselves each and every day while driving. Hearing the whining on the news is laughable. I'd love to go on the news and give the my 2 cents.. but that's not what brings the ratings I guess!!

 

Welcome to the real word of front wheel drive trains!!!

 

I use "B" all the time in braking. Been doing it ever since I bought my 2007 Prius new. Just had the 30k mile check. No problems at all. Plus my (original) brakes are at 75% still. Tire treads a-ok.

The manual for Prius states that using B DOES give you regen so whoever said it doesn't is flat out wrong. I read that when I got the car and that's what prompted me to start using B.

As for it being unsafe for drivers behind me, that's a good point. So far, not been a problem for me though since B doesn't give drastic deceleration. It only works when you've got a long stretch before having to stop and you have to time it just right so that you have to use only minimal brake at the end. "B" won't work for speed demon Prius drivers. You've got to be going relatively slow to begin with. I don't think using B gives any major undue surprises to the drivers behind me though I might be wrong.

 

I don't believe that anyone said that there's no regen when using B.

What I said was that when you use B, you can hear the gasoline engine rev up. Obviously, revving up the engine uses more energy than would be consumed if the engine was at normal speed. That energy will not be routed into the battery, but instead becomes added engine heat as a result of frictional losses.

Some energy will be developed via regen, but not as much as would be available if you left the shift selector in D and applied the brakes when you want to slow down.

When you use B, all you are doing is revving up the engine, compared to being in D. There's no wear on the brakes or any other component. You should not expect any impact besides worse mpg than you would realize if you left the car in D.

Hope that clarifies the issue for those who were confused by my comments.

 

Appreciate your comments on use of B. When I first read about B in the manual, it sounded analogous to leaving a manual trans vehicle in a lower gear while descended a steep incline. I have one such incline I go up and down each day. So I use B every day and thought it would lengthen brake life. Having read your thoughts and in veiw of what I've learned about regen braking, I'm not so sure. Any comments on brake life with respect to use or non-use of B?