Brake usage on cars with auto vs manual transmission

[Speedy]

billb wrote:
[quote=Black]
[quote=Speedy]
[quote=billb]shifting without the clutch isn't used much either but it sure can be fun to do

Routine in big trucks except when in the lowest couple of gears.
Why/ what's the benefit? left leg wear and tear
Yup.

[Black]

Speedy wrote:
[quote=billb]
[quote=Black]
[quote=Speedy]
[quote=billb]shifting without the clutch isn't used much either but it sure can be fun to do

Routine in big trucks except when in the lowest couple of gears.
Why/ what's the benefit? left leg wear and tear
Yup. Oh.

[JoeH]

Speedy wrote:
[quote=billb]
[quote=Black]
[quote=Speedy]
[quote=billb]shifting without the clutch isn't used much either but it sure can be fun to do

Routine in big trucks except when in the lowest couple of gears.
Why/ what's the benefit? left leg wear and tear
Yup.
One big downside in some places, it can get you fired. Place I worked driving buses had a policy against shifting without using the clutch, they fired a couple drivers over their violation of the policy. I know we weren't the only place around with that policy.

[Article Accelerator]

space-time wrote:
I drove only manual cars so far and my brakes will last 60-65k miles (front disk) or about 130-140k miles (rear drum). On both cars, both me and my wife. I guess we just downshift sometimes to slow down, don't rely only on brakes. This is mostly suburb driving with occasional long trips on highway.

Very similar practice and conditions to ours but our car has discs all around. The car now has traveled 200,000 miles and we just put on the second set of pads.

I just bought a van, auto transmission, disk both front and rear. Looking at maintenance records, seems previous owner replaced brake pads about every 25-30k miles.

I had an Oldsmobile sedan that couldn't go more than 12,000 miles between brake jobs. Disgusting.

I think your supposition regarding manual vs. automatic transmissions is on the right track but it seems to me that some brake designs or implementations are just bad.

[Article Accelerator]

DRR wrote: As for downshifting instead of braking, just know that that puts additional stress on the motor, the transmission, and increases fuel economy, versus braking.

It's a matter of technique, i.e. matching engine speed to gear rather than using the clutch to 'drag' the engine revs up on downshift. In other words, there's no need to wear the clutch at all during downshift (or upshift for that matter on anything but starting from a standstill).

[Black]

I missed that DRR initially stated that downshifting increases fuel economy....

[cbelt3]

2008 Chrysler minivan goes about 15K miles between brake jobs. OVER disgusting. They used cheaper brake system from a passenger car for a vehicle that weighs a good 1,000 lbs more. 2002 Civic got its first front brakes at 90K miles. Rears are still OK at 160K. Had to do the fronts again at 160K.

I downshift rather than use brakes. Downshifting doesn't use fuel, it just uses engine compression to slow the vehicle. Basically potential energy is converted into compression, which is then blown out the exhaust. I usually only use brakes if I have to stop NOW, or under about 10mph (I don't downshift into first).

Brakes merely convert potential energy into heat. Bleah.

[Filliam H. Muffman]

On deceleration, a lot of vehicles with fuel injection turn off the injectors when the throttle is closed and the engine is over 1500 - 1900 RPM. The exact RPM varies with manufacturer and engine. Very little fuel will be used on deceleration.

Another thing that can greatly extend the longevity of brake shoes, is having a hybrid. Brother's GF has a 1st gen Highlander. It is pretty close to 100k and the brakes are just about to need replacing. If you look far enough ahead while driving and use regenerative braking as much as possible, I could see brakes lasting 150k easy. She lives on a hill and the engine barely runs for the first 3 miles.

[SDGuy]

Article Accelerator wrote:
It's a matter of technique, i.e. matching engine speed to gear rather than using the clutch to 'drag' the engine revs up on downshift. In other words, there's no need to wear the clutch at all during downshift (or upshift for that matter on anything but starting from a standstill).

:agree:

Everyone should learn how to double-clutch.

My 1995 del sol still was on its original brake pads in 2010 (right around 160K miles), when it's lifespan was unceremoniously brought to a sudden end by a young woman in a Chevy Tahoe who decided that Stop signs are optional.

[M A V I C]

As to the original question, the type of car, type of driving, weight of vehicle, parts used... all have more of an impact than automatic vs manual.

Filliam H. Muffman wrote:
On deceleration, a lot of vehicles with fuel injection turn off the injectors when the throttle is closed and the engine is over 1500 - 1900 RPM. The exact RPM varies with manufacturer and engine. Very little fuel will be used on deceleration.

Yep. On my DD it's about 1200 RPM. It's my first manual with fuel injection. Previously I would push the clutch in and coast. I tried that when I first got this car, and noticed my fuel economy went down.

SDGuy wrote:
[quote=Article Accelerator]
It's a matter of technique, i.e. matching engine speed to gear rather than using the clutch to 'drag' the engine revs up on downshift. In other words, there's no need to wear the clutch at all during downshift (or upshift for that matter on anything but starting from a standstill).

:agree:

Everyone should learn how to double-clutch.
You don't have to double-clutch to do rev matching. You can release the clutch at the same time as the revs are matched without any additional ware.