Hot spots on a rotor

[dphatch]

Just took the ' 08 Infiniti to the dealer for a few issues one of which was what appeared to me to be a near perfectly straight lateral crack running from just beyond the hub to the outside edge of one of the front rotors. Rotors are not cross drilled or slotted and have 14K miles on them. Dealer tells me it is a hot spot on the rotor and there are a few others and it's no big deal. Have never seen this type of mark on a rotor before and have never heard the term "hot spots" with regards to rotors. Can someone offer their learned opinion as to the issue of "hot spots" on a rotor along with potential causes and any safety issues that could develop as result ?

[70Sixter]

It is easy to put hotspots on your rotors if you stay on the brake pedal after a hard braking stop. The heat around the pads will not dissipate like the rest of the rotor. Thinner the rotor, worser the problem.

Not sure about safety, but I'd err on the conservative side and replace them. I take it the rotor thickness was in spec.

[PAULSPEED]

I replaced a set of front rotors. I think they cost about

$100 each. Not bad for a Porsche part. Use Sunset

Imports for the best price.

Paul

[dphatch]

Thanks for your reply guys. I don't really do any hard braking in this vehicle s it's driven in town at modest speeds, but am glad to hear there actually is such a thing as hot spots on the rotors and that it's not a safety issue. I will ask the tech if he measured the rotor thickness to check for excessive wear. Still find it odd I have never noticed these hot spots on the rotors of other cars I have owned over the years. Am wondering if it's function of the design and/or quality of the discs themselves or a brake cooling issue.

The Infiniti discs run about half that for the fronts so will replace with first pad replacement. Sounds as if the spots my well return though. As for my Porsche brakes, they're fine with about the same mileage on them and I suspect they'll go a good bit longer before needing any sorting out.

[1schoir]

Thanks for your reply guys. I don't really do any hard braking in this vehicle s it's driven in town at modest speeds, but am glad to hear there actually is such a thing as hot spots on the rotors and that it's not a safety issue. I will ask the tech if he measured the rotor thickness to check for excessive wear. Still find it odd I have never noticed these hot spots on the rotors of other cars I have owned over the years. Am wondering if it's function of the design and/or quality of the discs themselves or a brake cooling issue.

The Infiniti discs run about half that for the fronts so will replace with first pad replacement. Sounds as if the spots my well return though. As for my Porsche brakes, they're fine with about the same mileage on them and I suspect they'll go a good bit longer before needing any sorting out.

IMHO, there has been a steady trend away from manufacturing quality rotors that used to get routinely resurfaced and trued about two times before they had to be replaced. Many of the current rotors seem to be geared to straight replacement at the first sign of a problem rather than having the capacity to be safely machined back to within specs.

I don't quite understand it because the minimum acceptable thickness of the rotor and the lateral runout specs stay the same, unless they are either starting out thinner than they used to be or are made of inferior materials, or both.

Regards, Maurice.

[PAULSPEED]

I replaced my fronts because there were crack lines running

between the holes. I also had some wear marks on them after I

did Laguna Seca. This track needs alot of brakes. I was

also running blue racing brake pads.

Paul