Cheap brake rotors

Where is the cheapest brake rotors to buy, mine are spent. I am going to try and turn the fronts but the backs are out of spec for sure. Also what is a good STREET pad, I dont track. Thanks in advance, as long as someone replies, HA.

Factory pads and rotors. Do NOT turn the rotors.

Agree with Dell.

I got a set of factory pads and rotors (front and back) for about $500 total from Sunset Porsche. They are THE cheapest.

Agree with Dell +2

disco - thanks, that is pretty cheap According to the shop manual Porsche allows 0.040" wear so I assumed you could turn the rotors half that or less and be within spec. I believe the rotors have about 0.010" to 0.015" wear right now. Just trying to save a little money for the holidays.

Related question: The dealer likes to replace rotors and pads together on a brake service. Makes sense when you replace brakes twice in 100k miles like I am sure many folks do. I drive mine street, daily. I use stock pads because of this. But I do 6+ DE's a year and can haul along pretty well. (read: those pads wear out fast!) Lots of folks seem to just replace pads and not the rotors when they burn thru pads at the track. I know the issue with the rotors is thickness. For DIY, how can I determine if I need rotors and pads, or just pads? Track buddies say they watch the rotors for micro cracks and replace them when they micro crack near the drill vent holes. This is a bit less scientific an approach than I usually like to take when going 100+ hehe. Any input? I need to get into the DIY brakes, am tired of paying dealer prices... How can I tell when rotors need replacment and when it isn't safe/right to just swap pads?

Your allowed 0.040" or 2mms of wear on rotors.

I'll take the 2mm.

Agree with Dell +3

How to check this? Do I need a special tool? Thanks.

....

your caliper reads 22.255mm in that picture, what is the original thickness of the rotor? I guess you need that to measure the 2mm of wear.. Thanks a lot

To get the original thickness couldn't you just measure the very edge of the rotor where the pad does not touch?

Im sorry, 2mm equals roughly 0.080" so that means you can take 0.040" off each side, that is a lot material. Sorry for the incorrect info.

Ah sweet! I need that tool. Any recommendations on brand / where to buy? What is that thing called? A brake rotor measuring tool? has to be a catchier name to it ...

it's called a micrometer.

I agree with Dell +3. You can usually tell if the rotor needs replaced (for thickness) based on the depth of the "lip" at the outer edge. When it's past the limit it's pretty obvious. I wouldn't bother turning them as cheap as new ones are.

Thanks guys! I've noticed the lip before on the rotors, so I know what you are talking about. 2mm is also good to know. I wasn't planning on turning them, I know that's not worth it.

Try Starret, they make decent precision tools.

If you want to buy mail-order try Enco .

You are correct. Since my 1997 Boxster is used, and I have the original front rotors, and 60k miles, I am not able to accurately measure the original thickness of my rotors. But, I can measure the lip....

I think I need to change my front rotors+pads since I can touch a lip on the rotor edges. Is the method below ok? 1. Buy a micrometer or vernier caliper. 2. measure the width at the lips/edge of rotor (from inner surface till outer surface) 3. measure the width just inside the lip/edge of rotor (from inner surface till outer surface) 4. see if the difference between #3 and #4 is 2mm or greater. Now the rotors are ventilated. So am I supposed to measure from outer (or inner) edge till the middle gap or directly between the outer and inner gap? My current understanding is that I'm given 1mm of wear on the inner surface and 1mm wear on the outer surface giving me 2mm total between the inner and outer surfaces of the rotor. The next phase is how do I measure the pad thickness (not rotor thickness)? And what are the recommended limits? This is for an C2 996, OEM pads mostly. Finally, where can I find pad options for the C2? This car is mostly street, so I'm taking the OEM route unless you guys have a better suggestion. Cheers !

I can't believe that the rotors do not have a "minimum thickness" spec engraved in them somewhere, this would be the first case I've ever heard of w/o this. I think that it must be a law, it's on every rotor and drum I've ever looked at. The reason for changing rotors goes beyond strictly thickness, the real problem is that they get heat-cycled too many times and it changes the quality of the steel. (More brittle/hot spots/etc...). This is also related to thickness, they get too hot and warp. All of these things obviously are amplified if you track the car or do any high-speed mountain driving where you really get the brakes hot and need maximum stopping and fade-resistance. My local track is the fastest in the west, (WSIR), but ironically is not a tough one on brakes. They stay reasonably cool there due to the layout of the course. In regular freeway driving, frankly the 996 has so much more braking performance than most cars that therefore if you are running @ 80-90% braking performance you would probably be OK. Not for me, though. I need 100%. The brakes are always the most impressive thing on a 911, BTW.

If you have to buy a tool to measure the thickness, get a digital caliper rather than a micrometer. You'll get a lot more use out of it.

...but difficult to measure rotor thickness if the rotor has any lip on it at all.

With the right tool it does not matter if the rotor has a lip.

Ditto. Every rotor I've ever put on a German car has had the minimum thickness engraved on the OD of the hub. I also can't imagine why one would turn a rotor. If it is thicker than the minimum thickness and not showing cracks, throw the new pads in and bed them in.

Thickness is one factor; warping is another (I had brand new rotors and they came warped!); also, if they're drilled, closely examine the cracks between the holes. If the cracks stretch to other holes, change the rotors with OEM only. I've owned "knock-offs" and they never worked for me over time. Don't turn them as they cannot be as dependable and predictable as new ones. It's just not worth the risk to you and your car if you get a major failure due to "short cuts."