conversion to 4 wheels disc brakes

Understood. Then it seems as though we agree more than we disagree

 

The main selling point for the Prius in the US is to get the best MPG, The fact that the US gallon is 3.78 Ltr and the Imperial gallon is 4.54 Ltr make this a hard sell.

The UK MPG is always stellar compared to US!

Ways to save fuel are decrease unsprung weight, that is fit 15 inch wheels, and fit drum brakes.

Also drums can be adjusted to spin free, discs always have a bit of drag from the light rubbing contact of the pads on the disc.

The only thing rear discs have for them is they look nice and shiny through the spokes of the wheels.

Drum brakes and small wheels save fuel.

Jon the Chief

 

Very good points. The bit of constant friction in those disc brakes probably does give you an extra few percent rolling resistance. Now I want to pin a number on that friction per disc brake! Gah!

Anyone want to buy me some lab equipment?

~ dan ~

 

6 to 7 times on 300.000 km?
thats a lot
i do this on a dodge(MB) sprinter only 100.000 km

maybe because off the automatie you need to change it more often?

 

besides regenerating heat energy

what is the difference between Prius brakes & regular disc brakes ?

btw if you install more aggressive pads & get stickier tires your stopping distance will drop

 

A few percent?? That's quite significant. I can spin a rotor easily (that's any properly adjusted rotor on any car I have ever worked on) easily with my little finger. I have driven highway speeds at long distances and even after a stop at the rest area (using light braking as usual) the discs are stone cold. In the overall scheme of things (tire friction, air resistance, engine waste heat, etc.) I would think disc brake resistance is hardly measurable in the Prius or any car for that matter.

Rick
#4 2006

 

Disc or drum brakes would make no measurable difference to fuel consumption. Drum brakes were used in the North American market because they could get away with it and it is cheaper. Drum brakes would have been laughed at in Europe. Drum brakes are cheaper because even with disc brakes there are drum brakes for the park brake anyway or a complex mechanism in the calliper. Remember in Europe there are an abundance of low fuel consumption vehicles unlike North America where gas guzzling is a national past time. It would be harder to break into the European market dominated by direct injection turbo diesels if the Prius had drum brakes.

The only way you will improve stopping distances is to use stickier tyres, ABS will reduce braking force to a skidding wheel whether that wheel has disc or drum brakes. By making the rear brakes more powerful you make it more inclined to lock, so if you can already activate the ABS on the rear axle increasing brake power is non productive. The same applies to increasing brake power on the front axle. Soft sticky high rolling resistance tyres are the first step in improving single stop brake performance.

If however you wish to improve multi stop brake performance there are most likely better ways than rear disc brakes.

Fit larger front disc rotors
Cross drill disc rotors
Groove front disc rotors
Drill vent holes in rear brake drum web
Drill vent holes in rear brake backing plate
Drill small well spaced vent holes in drum periphery. (Like all these suggestions, at your own risk)
Fit 4 spot callipers front & increase rear wheel cylinder diameter
fit flexible ducting directing cold air at brakes
Paint the callipers red. (joke)

To improve pedal feel fit more rigid callipers (Brembo or AP Racing and stainless braided flexible brake hoses. DOT approved of course.

 

I guess one option would be for the American's to import a Prius from Australia, which of course has four-wheel discs as standard. A bonus would be you would have the steering wheel on the 'right' side of the car!

Maybe not...

 

Not according to Mawcawfee.

 

A very good point, those cars over the USA are very confusing, what were they thinking puting the steering wheel on the left? Do American drivers have really long arms and legs?

 

With EBD and Regenerative braking, the Prius has excellent stopping performance and great brake component wear expectancy.

Certainly, more efficient tyres and suspension than are fitted as standard to the US (non-Touring model) cars will help with both braking and handling, but a major brake component replacement job is a fairly expensive way to get more improvement (assuming you can source the necessary replacement components in the US anyway).

 

LOL. Sorry, buddy. We invented modern driving of a modern car, therefore we decide which side of the street is the correct side and which side of the car is the correct side for the driver.



~ dan ~

 

IIRC the origin of which side of the road to travel on comes from which side you carry your spear/shield/sword on...

 

No, no, no. It relates to the circular staircases in castles. They always circle clockwise from the bottom - that is to the right.
But hang on, America never had any castles. Ah, they have tornadoes and they go anticlockwise. Therefore the USA motorists should be driving on the left.

 

The side of the road we drive on depends on a lot of things, least of all swords and spears. It mostly had to do with the type of transport used most popularly. This is a very interesting web page about it,
http://www.brianlucas.ca/roadside/

This is interesting

So it seems somewhere along the line, probably as a result of the civil war and breaking away from England the USA messed up and switched to the wrong side of the road.

 

In small-is-beautiful England, though, they didn't use monster wagons that required the driver to ride a horse; instead the guy sat on a seat mounted on the wagon. What's more, he usually sat on the right side of the seat so the whip wouldn't hang up on the load behind him when he flogged the horses. (Then, as now, most people did their flogging right-handed.) So the English continued to drive on the left... Keeping left first entered English law in 1756, with the enactment of an ordinance governing traffic on the London Bridge, and ultimately became the rule throughout the British Empire.

The first known keep-right law in the United States was enacted in Pennsylvania in 1792, and in the ensuing years many states and Canadian provinces followed suit. In 1792, Pennsylvania adopted legislation to establish a turnpike from Lancaster to Philadelphia. The charter legislation provided that travel would be on the right hand side of the turnpike. New York, in 1804, became the first State to prescribe right hand travel on all public highways. By the Civil War, right hand travel was followed in every State. Drivers tended to sit on the right so they could ensure their buggy, wagon, or other vehicle didn't run into a roadside ditch.

There.

 

Very well-argued, with complete documentation. And what's more is it's easily confirmed online. I don't know whether to give in, admit defeat, and confess that Americans are also driving on the wrong side of the road, or get picky about wagons versus cars... I do not know; I think you've got me!

~ dan ~

 

disc brakes are better than drums. and dont need to be adjusted.
if you have to jam on braks the discs are more likely no to lock oup than the discs.

 

I think you meant, "The discs are less likely to lock up than the drums."

But the REAL danger with drum brakes is after the first panic braking -- if you need to do it again or press harder after you jam them on the first time, you're toast because they'll have overheated.

~ dan ~

 

The only way you are going to lock up a set of drums (or discs) in the Prius is if ABS decides to go on holiday.