Time for new brake rotors?

[lonesoldier84]

They are looking rusty. Only been couple weeks since I banged up my knee and they are brown.

Kind of cut up too, not looking like theyre in great shape.

Question: when should you replace brake rotors?
I'll post pictures tonight (of the brake rotors, not of myself posing seductively, though if there is enough demand......)

 

[GConn]

I would replace rotors when they got warped or got visible cracks on it. Good question. I'd like to hear more technical opinions from people that know a few more things though...

P.S. Rust usually goes away with braking. It needs to be very nasty to impair the contact of the pad & rotor.

EDIT:

Having collected all the information needed to decide whether or not to replace the Brake Discs. Here are some further considerations:-

1. Brake Discs should last about two times the life of the Brake Pads, this varies from one car to another.

2. If the minimum thickness has not yet been reached the but the discs are within say 0.5mm of it. If Pads only are fitted by the time they have done a full term the discs will be considerably past the minimum.

3. If Discs need to be replaced independently later, the Brake Pads will again have to be replaced therefore doubling the cost of Pads and labour.

4. If scoring cracks or corrosion was found or any brake judder was experienced the Brake Discs should be changed to rectify these problems even if they were found to be over the minimum thickness.

 

[deeptekkie]

For tonight let's just stick with pics of the brake rotors, okeedokee? =:-O

 

[Maverick]

From the 2007 Service Manual...

CHECKING THE FRONT BRAKE DISCS

The following procedure applies to both brake
discs.
1. Check:
• Brake disc
Damage/galling → Replace.
2. Measure:
• Brake disc deflection
Out of specification → Correct the brake
disc deflection or replace the brake disc.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Place the vehicle on a suitable stand so
that the front wheel is elevated.
b. Before measuring the front brake disc
deflection, turn the handlebar to the left or
right to ensure that the front wheel is stationary.
c. Remove the brake caliper.
d. Hold the dial gauge at a right angle against
the brake disc surface.
e. Measure the deflection 2–3 mm (0.0787–
0.1181 in) below the edge of the brake
disc.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
3. Measure:
• Brake disc thickness
Measure the brake disc thickness at a few
different locations.
Out of specification → Replace.
4. Adjust:
• Brake disc deflection
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the brake disc.
b. Rotate the brake disc by one bolt hole.
c. Install the brake disc.
NOTE: Tighten the brake disc bolts in stages and in a
crisscross pattern.
d. Measure the brake disc deflection.
e. If out of specification, repeat the adjustment
steps until the brake disc deflection is
within specification.
f. If the brake disc deflection cannot be
brought within specification, replace the
brake disc.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲


Brake disc deflection limit 0.10 mm (0.0039 in)
Brake disc thickness limit 4.5 mm (0.18 in)
Brake disc bolt 18 Nm (1.8 m·kg, 13 ft·lb) LOCTITE®

 

[Fred]

They're rusty because they're steel and they haven't been used.

The first time you hit the brakes, they'll turn shiny again.

Don't replace them just for rust.

Fred

 

[Norbert]

They're rusty because they're steel and they haven't been used.

The first time you hit the brakes, they'll turn shiny again.

Don't replace them just for rust.

Fred

Yeah it's nothing to worry about.
It happens when you don't ride often enough. :spank:
Just hit the brakes a bit next time you ride to scrub them clean.

 

[lonesoldier84]

torn ligament in knee gents. not by choice.

I havent replaced the discs in all the time ive had the bike and she has gone through i think 2 sets of brake pads and is on the third set. I think I will replace it all. Discs and pads. ****ty thing is I still have pads left. And I'm poor. I guess I could put this off a month, and sacrifice the aesthetic mods.

Pics coming tonight. Resting my leg right now dont want to look around for the cable.

1) What are "scoring cracks?

2) How do you measure deflection?

3) Those triangle things are cool.

 

[lonesoldier84]

You will notice the rear brake pads
displaying an odd wear pattern with one
pad seeming to wear a bit more than the other.
Should I be concerned?

Rest of the pics are self explanatory.

 

[lonesoldier84]

 

[Norbert]

What type of pads do you use?
What have you used in the past?

 

[lonesoldier84]

the pads are made by SBS and are sintered metal i think....but am not positive they are sintered metal. bought them quite a while ago and just asked for basic replacement pads and took what they gave me.

 

[RJ2112]

Your right front rotor looks like it's developing grooves. Outside face, coming off one of the holes..... I'm cheap so I'd still replace just the pads. The more correct answer would probably be to replace at least that one.

You need calipers to measure the rotor thickness. The ruler will only show you the edge, which is not swept or worn by the pads, so it doesn't tell you what you need to know. Got to reach into the area used by the pads, to tell what remains of the rotor.

The rotors are actually more of an Iron than a steel, quite soft comparatively so the pads can 'bite'. Sintered metal pads wear the rotor much more quickly than organic pads do, because they spot weld the bits of metal to the rotor, then break it right back off with the rest of the pad material. Each 'stick and yank' pulls off some of the rotor...

 

[lonesoldier84]

bah!

so where can i get these calipers from?

but even if the rotors are getting a bit thin.....that's still ok....right?

keep in mind I am not a wealthy man....

 

[SirIsaac]

so where can i get these calipers from?

Well, [ame="http://www.amazon.com/Fowler-NSK-72-234-222-Brake-Micrometer/dp/B000R6TRPQ/ref=sr_1_25?ie=UTF8&s=hi&qid=1275582708&sr=1-25"]here's one [/ame]made specifically for the task at hand.

Kind of pricey for infrequent use. Something like[ame="http://www.amazon.com/QUINT-GRAPHICS-36-101-iGaging-Micrometer/dp/B0031EM4CO/ref=sr_1_31?ie=UTF8&s=hi&qid=1275582708&sr=1-31"]this [/ame] or [ame="http://www.amazon.com/iGaging-0-1-Digital-Outside-Micrometer/dp/B0031EICNE/ref=sr_1_29?ie=UTF8&s=hi&qid=1275582708&sr=1-29"]this[/ame] would probably work OK.

 

[lonesoldier84]

oh i see what you mean. i think i can find those in a local shop. cheers.

but what if my rotors are a bit thin? can i still use them? i know i probably shouldnt...but will it really matter if i do it now or a month or two from now? I'd do it before coming on that epic west coast trip thats for sure. but delaying till then is ok?

i will be doing some track days between now and then too.

 

[RJ2112]

oh i see what you mean. i think i can find those in a local shop. cheers.

but what if my rotors are a bit thin? can i still use them? i know i probably shouldnt...but will it really matter if i do it now or a month or two from now? I'd do it before coming on that epic west coast trip thats for sure. but delaying till then is ok?

i will be doing some track days between now and then too.

Thickness is important for heat dissipation. The minimum recommended thickness is a 'worst case' minimum. High stress use. Like track Days. Overheated rotors warp.

I would not want to rely on thin rotors in heavy use. Measure them, and make a good decision

 

[sniff6]

Just Remember your brakes are more important than your throttle!!!!Your call

 

[GConn]

^Why???? Brakes are for slow people

 

[lonesoldier84]

I will swap my rotors and my pads in a couple weeks. Until then I will go easy on the brakes and delay my track days.

Thanks all.