Does anyone know off hand what is the minimum front rotor thickness is or a
1998 SL2, I didn't realize it is casted on the rotors when I changed the
pads. Thanks in advance!
Brian

It may be 0.625 inches (15.8mm), but I'd definitely get another opinion. If
you had the rotors turned down, then the shop that did the work would have
made sure they were still more than the minimum before returning them to
you.

Bob

"Brian" <brianmc4 (AT) comcast (DOT) net> wrote

"Bob Shuman" <no_spam_thx (AT) sbcglobal (DOT) net> wrote

.. If
Don't bet your life on it.

At one time they were commonly marked. I suspect that since so few people
now waste money on turning down rotors that the mfgs no longer bother to
mark them.

New rotors are cheap, IMHO they should be changed when new pads are
installed.

They are all still required to carry the minimum thickness dimension. If a
shop turns them down beyond that dimension, then they risk litigation if you
are involved in an accident so most are extremely cautious/conservative in
what work they choose to do.

As to turning rotors versus replacement, and choosing imported Chinese (much
cheaper) ones over US made (more expensive) ones, everyone can make their
own personal choice and live with the results.

Bob

I find it quite ironic that you used the phrase "don't bet your life on it"
cause that is exactly what you are doing here when you install inferior
parts to your front disc brakes.

"Private" <please (AT) dont (DOT) bother> wrote

"Bob Shuman" <no_spam_thx (AT) sbcglobal (DOT) net> wrote

IMHE the worst rotors are the Saturn OEM ones, who knows where they are
sourced but I bet they were the cheapest available and probably offshore.
The rotors I choose are in no way inferior and IMHE are far superior to the
OEMs. When they are carefully compared side by side with rotors costing 3x
as much I am unable to see any difference, even the packaging was similar.
The distributor I buy from says the cheap ones outsell the expensive ones
5-1 and he has never had a comeback. I think you will find that the
expensive ones are also sourced offshore and merely rebranded for the price
difference. YMMV

ANY turned rotor is starting out thinner and we all know size matters. IMHE
thicker rotors are much less likely to warp and new rotors with unrusted
cooling slots will also cool faster and more evenly, the unrusted mounting
faces will seat flatter on the hub, which along with uneven torquing is
often the real cause of warping or uneven runout.. IMHE new rotors have a
much nicer finish that any turned down used rotor. IMHO rotors are
consumable items and I would not attempt to extend the life of rotors
through two sets of quality pads and while I am replacing rotors well before
they have reached there minimum service thickness, but doubt that turned
rotors will still be above their min thickness through the entire service
life of the second set of pads. YMMV.

I agree that we must all make our own judgments as to serviceability,
comfort level and perceived quality, I have found no necessary correlation
between quality and price. YMMV.

"Private" <please (AT) dont (DOT) bother> wrote

I c an't comment on the Saturn original equipment since we picked up the
Saturn in our family with 112K miles and the brakes had been done at least
twice already and the rotors had been replaced. I'll take your word that
they were lousy based on personal experiences with several other new
vehicles I have purchased.

I agree with everything you've said here. The key point is how much thinner
and lighter the current vintage of rotors are compared to what were used
back in the 60's and 70's! To combat warping, I've found that using a
torque wrench to set all lug nuts to the same spec seems to help. I even do
this any time I've had work done by someone else, like a front end
alignment, new tires, etc.

I do not agree with you here. I've had the experience of purchasing brand
new, shiny, right out of the box Chinese made rotors that caused vibration
and pulsing. They actually needed to be turned and this fixed the problem.
There is no explanation for this other than shoddy quality plain and simple.
Although not a scientific strudy, I've never had this happen when purchasing
more expensive Raybestos US-made rotors.

IMHO rotors are
This depends on the vehicle, the brake pad material, and the driver's
habits. I have always managed to get at least one additional brake job out
of the more expensive rotors and in some cases, two. For our Saturn SL,
using the cheaper rotors is probably not a big deal since the car is so
light and the brakes tend to wear pretty well. I'd never do this though on
my family Chrysler minivan since the brakes on that vehicle are
under-engineered.

I do agree that higher price does NOT always guarantee higher quality and
that automotive engineers in their quest to increase MPG have reduced so
much mass that the rotors have become consumables. I find nothing wrong
with doing what you are doing if it works for you, but caution readers to
exercise good judgement based on their specific circumstances.

Bob

"Bob Shuman" <no_spam_thx (AT) sbcglobal (DOT) net> wrote

I think we are in substantial agreement, especially regarding the lightness
of modern rotors, these are the first vehicles I have owned that required
regular replacement. To be fair the cost of new rotors is barely higher
than the cost of machining and if the convenience of buying new rotors and
pads vs, the extra trips that must be made after the car is disassembled in
order to machine the rotors, purchasing new rotors is actually cheaper.

I have purchased two new Saturns, both required replacement of the front
rotors due to corrosion (high temp) failure of the inside surface well
before the pads were fully worn. I get ~75k mi from the OEM and more from
the replacement parts on the second cycle. I have had no corrosion problem
on the replacement rotors. The majority of usage is highway in the Rocky
Mountains, occasionally fully loaded. I do believe that heavy brake use
indicates less than optimal driving for fuel economy.

Happy trails,