'2000 300M: Front rotor thickness?

[MoPar Man]

'2000 300M, 67k km (41.5k miles).

Just put my snow tires on (Alpin's on front, Blizzak's on back), was
checking the rotors and pads. Changed front pads about 1.5 years ago
because of "groaning/creaking" of original pads, so they're still
good. Changed rear pads (probably still 1/2 the pad left but what the
hell.) Boy they're small. Still looking for something to cover the
center hubs.

Measured the front rotors - both at 1.02". What is the original
thickness? (I looked but couldn't find any numbers stamped on them
other than a 5 or 6-digit part number.) This is non-PHP. Rear rotors
had lots of text stamped on them.

You know, all the stuff about vented rotors is crap. Ever notice how
much the outside faces rust to the point where all the venting is
jammed up?

Preliminary numbers (based on just over 6k miles) indicates slightly
more than 3k miles per 1/32 tread wear on the summer tires (Dunlop
Sport 5000 - usually kept at 33 psi). Very rough figure is that these
tires are good for 25k miles (if end-point is 2/32 tread). Will
probably take another summer's worth of driving to get a better handle
on tread wear rate.

 

[Bill Putney]

'2000 300M, 67k km (41.5k miles).

...Measured the front rotors - both at 1.02". What is the original
thickness? (I looked but couldn't find any numbers stamped on them
other than a 5 or 6-digit part number.) This is non-PHP. Rear rotors
had lots of text stamped on them.

I think by federal law the min. thickness has to be on there - but rust
does make them hard or impossible to read sometimes.

Front (specs. same regardless of PHP/non-PHP):
Original thickness 25.87-26.13 mm (1.019-1.029 in.)
Min. allowable thickness 24.4 mm (0.960 in.)

Rear:
Original thickness 11.63-12.13 mm (0.458-0.478 in.)
Min. allowable thickness 10.4 mm (0.409 in.)

You know, all the stuff about vented rotors is crap. Ever notice how
much the outside faces rust to the point where all the venting is
jammed up?

I disagree that that means the stuff about venting is crap. I think
what it means is that as rust gets thicker (and forms scales) and clogs
up the vent paths that the rotors are more prone to warping. In
general, venting aside, I'm not sure if light rusting helps by
increasing surface area for cooling or hinders by insulating - maybe
offsetting effects. But definitely scaling rust would decrease cooling
(especially in the vents).

Preliminary numbers (based on just over 6k miles) indicates slightly
more than 3k miles per 1/32 tread wear on the summer tires (Dunlop
Sport 5000 - usually kept at 33 psi). Very rough figure is that these
tires are good for 25k miles (if end-point is 2/32 tread). Will
probably take another summer's worth of driving to get a better handle
on tread wear rate.

That's why I don't buy so-called "high performance" tires - a lot less
value for the money than a good touring tire IMO.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")