Setting Toe

That's what I hadn't considered - I haven't had to do four wheel alignment
before. While I imagine it could be done with a similar procedure (measuring
rear wear and torque steer besides the front part) it makes a lot more sense
to take that to a pro.

Mike

 

retrogrouch!

in reality, disks offer better cooling, therefore less fade. they also
offer more linearity between pedal pressure and braking effectiveness.
for a vehicle that potters about town getting groceries, this is not an
issue, but for one that gets driven hard, these benefits cease to be so
theoretical.

 

retrogrouch!

in reality, disks offer better cooling, therefore less fade. they also
offer more linearity between pedal pressure and braking effectiveness.
for a vehicle that potters about town getting groceries, this is not an
issue, but for one that gets driven hard, these benefits cease to be so
theoretical.

 

Who, me? Nah...

Absolutely. Which is why *real* performance cars used in *actual*
performance applications use them.

True again (you're on a roll here, jim...)

My point exactly. A grocery-getter (which describes 99% of road-going cars)
does NOT need rear discs, and in fact is adversely affected by their
presence.

 

Who, me? Nah...

Absolutely. Which is why *real* performance cars used in *actual*
performance applications use them.

True again (you're on a roll here, jim...)

My point exactly. A grocery-getter (which describes 99% of road-going cars)
does NOT need rear discs, and in fact is adversely affected by their
presence.

 

Nor did I, back in the dark days of early 1991...

My famous 1991 Integra famously has those infamous rear discs...

Ever driven un-powered 4-wheel drums? GAWD they were awful. Terrible! Plan
your stops in advance, preferably in writing.

And it was akin to a religious conversion: YES LAWD, AH SEE THE LIGHT!!!
Discs were a sea-change compared to drums.

Yep. But there is a point of diminishing returns, and rear discs was it.
For road-going, legal speed, grocery-getting FWD cars, of course.

 

Nor did I, back in the dark days of early 1991...

My famous 1991 Integra famously has those infamous rear discs...

Ever driven un-powered 4-wheel drums? GAWD they were awful. Terrible! Plan
your stops in advance, preferably in writing.

And it was akin to a religious conversion: YES LAWD, AH SEE THE LIGHT!!!
Discs were a sea-change compared to drums.

Yep. But there is a point of diminishing returns, and rear discs was it.
For road-going, legal speed, grocery-getting FWD cars, of course.

 

Just one question...If disks are so much better, why do the large trucks and
tour buses still use drums on all axles? I know there are some exceptions
but most use drums. I hadn't really considered this until your above
comments...

Dave D

 

Just one question...If disks are so much better, why do the large trucks and
tour buses still use drums on all axles? I know there are some exceptions
but most use drums. I hadn't really considered this until your above
comments...

Dave D

 

very few of the modern tour buses use drums these days, or at least, not
on the front.

the main reason drums are still used on large trucks, especially big
rigs, is because of the air brake thing. unlike cars and lighter
vehicles, they're "fail safe" which means their "natural" position is
full on as opposed to off like a car. strong springs inside the drums
press the shoes real hard against the drum, and the air system actuates
against the springs to hold the shoes off the drum so the vehicle can
roll. if the braking system fails, the brakes come on, and the 30+ ton
cargo comes to a halt. hopefully. "fail safe" is much more complicated
to implement on disk brakes, but real simple inside a drum. plus imo, a
lot of domestic truck manufacturers are not exactly innovative pioneers
in the engineering department - the quality of the chrome plating seems
to get more attention from what i can see.

 

very few of the modern tour buses use drums these days, or at least, not
on the front.

the main reason drums are still used on large trucks, especially big
rigs, is because of the air brake thing. unlike cars and lighter
vehicles, they're "fail safe" which means their "natural" position is
full on as opposed to off like a car. strong springs inside the drums
press the shoes real hard against the drum, and the air system actuates
against the springs to hold the shoes off the drum so the vehicle can
roll. if the braking system fails, the brakes come on, and the 30+ ton
cargo comes to a halt. hopefully. "fail safe" is much more complicated
to implement on disk brakes, but real simple inside a drum. plus imo, a
lot of domestic truck manufacturers are not exactly innovative pioneers
in the engineering department - the quality of the chrome plating seems
to get more attention from what i can see.

 

I drove a '67 Chevy Biscayne (like a low end Impala) with unpowered 4-wheel
drums down a long shallow descent in California when I was a new driver.
Within a couple miles I had both feet braced on the brake pedal and was
hoping for a place I could coast to a stop. The tranny was a 2-speed
"Powerglide" (more glide than power) so low gear was just keeping my speed
below 50 mph. I wanted my mommy!

Mike

 

I drove a '67 Chevy Biscayne (like a low end Impala) with unpowered 4-wheel
drums down a long shallow descent in California when I was a new driver.
Within a couple miles I had both feet braced on the brake pedal and was
hoping for a place I could coast to a stop. The tranny was a 2-speed
"Powerglide" (more glide than power) so low gear was just keeping my speed
below 50 mph. I wanted my mommy!

Mike

 

The worst car I ever personally drove was a 1974 Nova with manual drums all
around. Now, a '74 Nova is not nearly a '38 Ford when it comes to brakes,
but it was still quite a culture shock when you're used to a vacuum-
assisted 1975 Japanese disc/drum setup.

So remind me again, how come the Japs got such a foothold over here in the
first place?...

 

The worst car I ever personally drove was a 1974 Nova with manual drums all
around. Now, a '74 Nova is not nearly a '38 Ford when it comes to brakes,
but it was still quite a culture shock when you're used to a vacuum-
assisted 1975 Japanese disc/drum setup.

So remind me again, how come the Japs got such a foothold over here in the
first place?...

 

Hate to disagree with you but every MCI coach I have driven in the past 10
years, including new ones, all had drums on all axles. I checked with our
shop chief and he says it has to do with the larger swept area of the
drum/shoe brakes as opposed to the disk/pad brakes. It is true that the
disks will not heat up as quickly and are less susceptible to fade and water
but the increased stopping power is the reason he gave me.

Actually, there are two systems at work there. The service brakes are
activated via an "S" cam and release when the pedal is no longer depressed.
You are quite correct, however, that in the event of catastrophic air
pressure loss, the failsafe system that you describe will lock up (full on)
all the brakes. Rather an unsettling experience I might add.

Dave D

 

Hate to disagree with you but every MCI coach I have driven in the past 10
years, including new ones, all had drums on all axles. I checked with our
shop chief and he says it has to do with the larger swept area of the
drum/shoe brakes as opposed to the disk/pad brakes. It is true that the
disks will not heat up as quickly and are less susceptible to fade and water
but the increased stopping power is the reason he gave me.

Actually, there are two systems at work there. The service brakes are
activated via an "S" cam and release when the pedal is no longer depressed.
You are quite correct, however, that in the event of catastrophic air
pressure loss, the failsafe system that you describe will lock up (full on)
all the brakes. Rather an unsettling experience I might add.

Dave D

 

http://www.mcicoach.com/parts-service-support/partsSpecialsNewsDrum2Disc.htm

euro coaches like setra & van hool have had them for more than a decade.

nope. see above.

 

http://www.mcicoach.com/parts-service-support/partsSpecialsNewsDrum2Disc.htm

euro coaches like setra & van hool have had them for more than a decade.

nope. see above.

 

Plus interstate buses and 18-wheelers are seldom bought on the strength
of some advertising campaign (as opposed to passenger vehicles), IMHO
anyway.