bam

We've now put about 1400 miles on the car in 2 weeks and 2 days of driving and the brake dust is very little. The wheel do have a light coat of dust/brake dust but the wheels are def not black. The car itself is dirtier than the wheels.

It seems that the regenerative braking and the brake pads used for this feature is what allows so little brake dust to coat the wheels or maybe it's efficient airflow design. I don't know if the RX350 has as little brake dust but either way, to lexus for allowing the wheels to stay relatviely shiny even after 1400 miles of driving.

Cruiter

It's the 'regen' system. If you search through the 2nd gen hybrid folks, you'll find most of them are going well beyond 120,000 miles on their original pads. Just another cost saving feature of the (h) models .

kitlz

Low to no brake dust is definitely a nice benefit with the 450h. The rims stay shiny for a long time. When I hit them with Sonax maybe every six to eight weeks, only the rotors turn a little red. It makes cleaning those extra spokes so much easier.

RXSF

its because when you are braking, you are not using the brake pads to stop since there is regen braking. No use of pads = no brake dust

bam

Are you sure about it not using the brake pads? I find this hard to believe. If I'm understanding you correctly, you're saying the car doesn't slow down by using brakes/brakes pads.

Can you explain how regenerative braking actually works because when I look at the wheel, it looks like there are calipers with brake pads so are those there for looks?

I'm sure the car is using brakes/brake pads to slow down but maybe these are special brake pads that convert the friction somehow to electrical energy which is then transferred back into the system and then stored in the battery. Afterall, what actually slows down a non-hybrid car is the friction created between the rotor and the brake pad and the brake dust is a byproduct of the brake pad wearing down.

I assume the brake pads are just made of a unique material that allows it to perform its primary function of slowing down the car but also able to recapture the lost energy/friction and convert it into electrical energy.

InRBigness

you are absolutely using the brake pads when you stop. You are also using the regenerative brakes but they are supplimentry. You can test this by putting it into neutral and slow down.

When you apply the brakes you energize the coils on the generator/electic motors which produces electricity. Think of them as little alternators connected to the wheels.

JimH2

See section on regenerative braking in the following article:

http://en.wikipedia.org/wiki/Hybrid_Synergy_Drive

Cruiter

That's an excellent link and good reading.

Bam, at normal speeds if you brake slowly (moderate braking), the electric motors can slow the car to a near stop. If braking faster or when coming to a full stop, yes the hydraulic brakes work for you. The majority of people driving a Hybrid, drive it for fuel efficiency and therefor learn the best braking techniques, IE: anticipate stops and decelerate early, braking moderately when possible. That's what keeps the wheels clean and very little wear on the pads and rotors.

RXSF

I guess I should should have been more thorough in my explanation but I was using my phone.

When you step on the brake pedal lightly, you are not using your brake pads. I am no engineer so they may be used a little bit, but the regenerative braking system does not use calipers to stop. What happens is the electric motor runs in "reverse" thus slowing the wheel down, and also acting as a generator to put electricity back into the battery pack. However, right when you come to a complete stop, the brake pads are used.

Also if you do hard braking, or if you brake over bumps in the road, the car will automatically use your brake pads and not regen braking to give you more effective braking

DunWkg

Regeneration begins as soon as you lift your foot off of the accelerator pedal. So the "braking" effect begins without touching the brakes. The amount of pressure on the brake pedal determines when the friction brakes, you see looking through the spokes of the wheels, begin to activate.

Before purchasing the hybrid, I had read a review that stated it takes a while to adjust to regenerativive braking. It's so seamless, I'm not sure there is an adjustment.

GoHuskers

I have no dusts on my wheels at all.

I always have hard time stepping into the 350 after getting used to the 450h brake system. You have to push harder and further to brake on the 350. I first thought I need new brake pads for the 350 but I thought that is to soon since the car only has 22,xxx miles. I asked my SA and he said that is Normal.

mikli

The brakes are one of the plus in these h cars.