Brake rotor damage does it need replacing?

[RDee]

Hi,
I spotted marks on the inside of the cooling vents (?) on my front rotor, see photos. Do they need replacing and any suggestions what the likely cause would have been?

The marks appear on most vents. If it is important/useful it is a road bike with ultegra hydraulic disc brakes which are about 4 years old and have done around 22,000km in all weather commuting. Also for what it’s worth the rear rotor appears to be fine.


Thanks in advance 👍

 

[raleighnut]

That's just muck/worn off pad material give it a good clean with 'brake cleaner'

 

[RDee]

That's just muck/worn off pad material give it a good clean with 'brake cleaner'

Great, thanks I will give it a good clean tonight 👍

 

[Cycleops]

Not just muck. There's a huge chunk out of it. You could keep on using it but your pad life won't be great. New rotor for sure. They're not expensive.

 

[fossyant]

Give it a good clean and double check. Aren't Ultegra disks a laminate sandwich rather than solid ? Potentially worn thin ?

I suspect that pitting could quickly damage your pads. 22,000 of commuting. They have probably done their job.

 

[Kbrook]

There’s a bloody great chunk missing, a new rotor is about £10 , throw it away

 

[Espresso vecchio]

There’s a bloody great chunk missing, a new rotor is about £10 , throw it away

The tiny pitting around the vents is unremarkable. Are Kbrook and Cycleops really thinking that the shallow asymmetrical V on the outer edge is a bloody great chunk missing? It's a normal feature of the rotor's rim!

 

[Cycleops]

You see, I'm not familiar with the upper eschellons and ratified air of Shimano's group sets so think I can be excused

 

[wafter]

It looks superficial, but I'd be intrigued to know what the cause is. Looks like corrosion but I thought these bits were stainless...?

Sounds like impressive mileage given the conditions; probably worth checking thickness against manufactuers' stated minimum

 

[RDee]

Thanks all for your views on this.
To complete the story I gave the rotor a good clean and there were areas where the braking surface had gone. I’m not sure on the exact cause probably just general wear, I have been through at least 4 sets of pads I think and have been riding generally on typical (bad) London roads in all weather and my commute involves a lot of heavy braking for red lights, etc.

Long story short, new rotor bought, £50 for a like-for-like replacement and all good now 👍

 

[wafter]

Thanks all for your views on this.
To complete the story I gave the rotor a good clean and there were areas where the braking surface had gone. I’m not sure on the exact cause probably just general wear, I have been through at least 4 sets of pads I think and have been riding generally on typical (bad) London roads in all weather and my commute involves a lot of heavy braking for red lights, etc.

Long story short, new rotor bought, £50 for a like-for-like replacement and all good now 👍

Good work - did you measure the thickness of the disks in the end? Would be interesting to know how much they'd worn in this time..

 

[RDee]

Good work - did you measure the thickness of the disks in the end? Would be interesting to know how much they'd worn in this time..

Sorry, I didn’t I’m afraid I don’t have a micrometer!

 

[gbb]

Possibly in the same way normal pads will pick up and embed small stone chips etc and will score normal wheel rims. Only difference may be those small chips are scoring the rotor instead of the rims.