News on 2005 Prius models?

It would be nice if my Prius could accelerate, stop, and corner as well as the 2002 GTI 1.8T that I traded for it, but then the Prius could not be a 50 mpg car. My point is that if one drives the Prius to obtain maximum fuel economy, larger wheels and rear disk brakes are not necessary.

Note, however, that the base VW Golf has rear disk brakes and 16 inch wheels.

 

Not all Disc Parking Brakes rely on mini-drums

http://ca.autos.yahoo.com/maintain/parking...es_answer1.html

 

personally i think that the need for disc brakes on the rear where you have only 20% of your stopping power is simply not there.

 

disc brakes have always had one other advantage in my experience - they have a lot less tendency to disappear when wet.

of course, i have not had a car with all drums in many years so maybe that problem has been solved as well, but i know when i first went to a car with discs in the front, i was pretty impressed at the difference coming out of a big puddle.

 

In general one wants to avoid locking the brakes, because a rolling wheel stops better except in unusual circumstances (such as deep snow) and allows some steering. Disc brakes offer more control against lockup than drums (maybe this matters less with ABS), greater water resistance, and greater resistance to fade. I would guess that in Europe, where many folks drive as if they are racing (perhaps as a matter of survival in traffic, perhaps because it is accepted in their country), brake fade could be an issue because the braking is episodic and aggressive, way too aggressive for regen or engine braking to help. In US conditions, fade is most likely on long hills, and it is there that the regen braking and compressional braking from the engine can effectively prevent fade. Also, with the strong front weight bias, the rear brakes don't do much. However, they are needed by the stability control system.

My opinions - (1) unless one is racing (or racing to the airport ...) drums are acceptable, but discs would have been a better choice simply because brakes are so important that even a small benefit is worth having. (2) Discs are supplied in those markets because buyers consider any car without them as too low-performance to be worthy of consideration; drums may have been acceptable tehnically, but not market-wise.

 

People in Europe drive like madmen... That's why we need better brakes...

Ah, well, maybe not. I can't think of any reason why you guys (and gals) in the US would not need disc brakes. Price could be an issue, but why would price be an issue for you and not for Japan and Europe? Weight could be an issue, but it's not as if the car gets significantly heavier from disc brakes, so the extra pollution is not that much to worry about.

/me is confused about this

And from Tempus' list, I'd like to see:
EV Mode
Daytime Running Lights
More Adjustable Drivers Seat
Rear Park Assist (Proximity beeper) (already an option over here)
Backup Camera
Integrated Side Mirror/Turn Signals I'd like these very much.
Extended Spoiler
Different Lower Front Fascia
3-D Navigation

 

well someone brought up a point about emergency brakes. with 4 wheel discs, how would emergency brakes work?

 

This is not correct. Disc brake calipers can be of several designs, most commonly drum-in-hat or what is called integral. The integral design exerts force via a lever arm to the piston to allow the parking brake function in a less complex and less costly manner than a drum-in-hat design. However, disc brakes are more expensive than drum brakes, in part because of the more complex parking brake that is required. Each can be sized to provide sufficient torque. Modern drums also generally have some sort of labyrinth seal to keep water out of the drum unless it is submerged. The more common complaint today is of initial fade when first applying the brakes when driving in rain, caused by water on the rotor being converted to steam and "outgassing," resulting in a layer of evaporated h2o between the lining and rotor. Lastly, drum brakes were traditionally less controllable than disc brakes, resulting in the early 1990's excuse that ABS required 4 wheel disc brakes. Today, improvements in the ABS controls and drum brake actuators have resolved these issues. This is purely a decision based on market acceptance and cost. In Europe, the price of market entry is disc brakes. In the US, the key to market success is low price. The drum really does not give up any performance for US drivers. It just saves Toyota money. With a top speed of only about 106 mph, the disc brake is not really buying the Europeans anything, it just costs someone money.

 

(In case anyone's still interested in the original topic of this thread...)

I just got on the wait list at a Chicago-area dealer, and I was told that I'd be getting a 2005 model later this year.

Apart from a $300 increase in sticker price, the guy said he didn't know of any changes being made in the car. That seemed logical to me since they just did a major overhaul last year.

They said the 2005's would be on the market starting sometime in the early fall.

 

I've had a '05 "On Order" since March.

Just told today by the Dealer ( Burien, Seattle )

"That is basically the factory making a decision to call the vehicle a 2005 model vs a 2004. There are no changes to the car."

PS -
They have 135 folks on their List a/o today.

 

i'd go for the "cost" outweighing performance and other requirements.

my '97 taurus (base SE model) had four-wheel disc brakes, and my neighbor's base '98 taurus had disc-front and drum-rear.

:?

 

Batavier, can you list stopping distances of the EU Prius? The US car has an unusually long stopping distance for it's segment from what I've read. I know there are other variables in the EU model like wheel and tire size, but it would be interesting to compare.

I'll bet your car has better brake pedal feel. The US car feels like I'm stepping into a bucket of putty and isn't very confidence inspiring. It stops OK the first time, but this is the first car I've driven in years that I've consciously added spacing distance to in the event of a panic stop situation developing at freeway speeds.

 

Rick, you know, I forgot all about the brake-by-wire thing. I remembered the electrically powered hydraulic booster like in my '00 Land Cruiser (please don't flame me) that has outstanding feel, but yeah that would go a long way toward explaining the squishy pedal feel. I'd still like to drive an EU spec car to compare, though. Maybe if we get lucky we'll eventually get EU specs here, if only for the more adjustable seats. Thanks for the refreshing explanation!

 

I've read other comments about brake feel and a supposed disjoint between regen and actual brake engagement. But the brakes in my '04 Prius feel very "normal" and natural to me. There's supposed to be some tactile indication of how hard you are pressing, in any brake system, to distinguish between gentle and hard braking. And my brakes feel just the way I want and expect them to feel. And I've never been able to tell when regen stops and actual braking begins. I think I've read it's at 8 mph (or if you step hard on the pedal) but I cannot feel the transition.

 

The parking brake on cars utilizes a cable which also is a backup safety device in the event a brake line bursts. Just remember that if your brake pedal pushes to the floor and you think "crap, no brakes" you'll still be able to step on the cable actuated parking brake. Of course unless your wife thought of that also and cut the cable.

 

Heh...


So we'll be hearing really soon what they're changing (or not changing) for 2005? Let's hope they add a color or two, switch around the packages a bit, and leave the price...