How long do your brake rotors last?
 

For me I noticed over time they get pretty warped, which happens sooner than they wear out from braking and because too thin (so they are ready for replacement).

I know I can try to straighten them with a tool however I found that's not easy plus I dont see a point of straightening if they will get warped after few descents again (maybe they wont, maybe they will I am just guessing).

Since they became warped I find it hard to adjust brakes well without they rubbing quite a lot so I feel like I would rather replace them (although they are not wear out).

Also, the other day I went to change rear rotor and there was quite a surprise waiting for me. I usually check my bike regularly and all that but I didnt see this so I am not sure when it happened, but 1 of the 6 rotors screws were gone and the other started to unwind.

What's pretty warped? If the are just going from one side of the gap between the pads to the other, then that's probably not enough to call them warped for me.

I've not had a rotor scrub hard enough on the pads to be an issue for riding. I have had them sometimes make a harmonic noise when I'm moving my bike around at home. But that doesn't mean they need any fussing with.

Yes you do need to keep your bolts tight on the rotors or the center lock if you have that. I recently found my rear lock ring on my center lock disc's a little loose and tightening that up fixed some funny noises I was hearing while riding that I wouldn't have identified with brakes.

I run expensive rotors, and I run cheap rotors; I've never had any warp enough to cause problems. I'm wondering if you have cheapie mechanical calipers that only push one piston against the rotor; if those are poorly-adjusted, the mere act of braking might flex the rotor.

I put a little drop of blue Loctite on the rotor bolts on my mtb. Still don't have a disc road bike but I've had disc mountain bikes for 14 years and I've only replaced one rotor in that time, and it was because it was worn thin. The rotors probably both need to be replaced now, that bike has seen some heavy braking while carrying a total load of about 245 pounds.

Well, enough to rub on one or both sides if the calipers are tight enough. I mean if the gap between brake pad and rotor is 1mm, and the rotor warps 1 mm to side, it will rub.

I only find my brakes work well if I tighter them as much as possible next to the rotors. Which only works if the rotors are straight.

Forgot to write, I have TRP Spyre brakes.

Blue Loctite and checking your bolts from time to time (as mentioned by previous posts) is the best route to success here, imo.

When the disc travels from side to side that 1 millimeter and rubs the other pad, is that more just a visual thing or are you actually... while riding the bike, feeling the scrubbing of the pads slowing you down? A pad touching the disc without putting sufficient pressure on it is not really a problem.

Maybe not a problem in terms of scrubbing actual speed, but definitely can be a problem in terms of pure annoyance. Rarely is rotor rubbing a silent affair.

Visually I can't tell that my rotors aren't rubbing on one pad all the time. There is no gap between the disc and pad on one side. However I don't have any noise while riding. Nor do I have any difference in wear between the two pads.

If you can't see or hear your rotors rubbing, and find no evidence that they've been rubbing, and don't notice that the wheels spin any slower, are they actually rubbing?

This might be more of a philosophical question.

Pretty much that is my point.

I feel that many of the people that always claim their rotors warped provide no evidence other than they appear to go from pad to pad as the wheel rotates. It simply bothers them and they go to great lengths to fix or attempt to fix something for no benefit. Except maybe their own insanity. However that doesn't necessarily indicate that there is an issue if it isn't causing a problem. A certain amount of warp is okay. Just like wheels have a tolerance for how true their rims are.

How do you tell if a rotor is worn? Assuming its not warped.

Measure the thickness. If you can't find a spec measure the area next to the brake surface for reference. Mine started at 3mm and one was worn below 2mm.

A rotor manufacturer might be able to provide a spec/recommended minimum thickness.

Blue loctite is my friend too:). Have fun and stay safe.

long enough that I don't worry about the replacement cost.

Yes, exactly that.

Its rubbing just enough to make annoying noises. Sometimes more sometimes less. Sometimes it bothers me, sometimes not, more does than not :D

I haven't tried floating rotors yet though (if they will warp less).

Use a caliper. When a Shimano rotor gets down to 1.5mm, it’s time for replacement. SRAM rotors get replaced at 1.55mm.

Wow. What kind of rotor started out 3mm thick? I don’t think that would fit in most calipers.

Oops, you're right. I just checked, it's just over 2mm in the thickest part. Must have been under 1.5 when I tossed it.
I'm old and get confused easily.

Problems described - If 6 bolt then it seems like they aren't being torqued properly or in the correct pattern. If you have them unevenly or improperly torqued then they will spring a bit when heated during braking.

Warp - fix it. If it continues then fix it correctly.

If you can't keep the rotor within the pad clearance easily then you probably have something else going on. Common causes:

1. caliper mounts on the frame are no longer flat and in the correct plane in relation to the axle. Solution: re-machine the mount
2. Caliper mounts are indented or scored so that when you line the caliper up while loose it's fine but when you tighten it the caliper moves. Solution: re-machine the mount
3. Piston(s) is(are) sticking. Solution: pull the pads, correctly advance a piston, clean it, apply a little bit of DOT grease for DOT brakes or a drop of mineral oil or DOT fluid for the corresponding brake systems. Press the pistons back into the bore and repeat the cycling the piston in and out until they float freely. Clean it all vigorously with rubbing alcohol. re install the pads and push the pistons and pads back as far as they go. Mount the wheel again and advance the pads with several pulls until brake power returns. This should allow the pads to freely advance and then freely retract when the brake is off. It will also allow an out of true rotor to easily push the pad back enough for clearance within a revolution or two.

Like all things on a bike - Disc brake rotors shouldn't be having major problems unless something is foundationally wrong with the setup.