OEM rotors for 1998 M3

Coupla quick points:

2) The rotors on your BMW are nothing particularly special. You can buy rotors from ATE, Brembo, Zimmerman, Balo, that are the equivalent to whatever you get over the parts counter at the stealership.

Check them out:

PS- My choice would be the Zimmermann non-drilled disks at ~$63 per front and $52 per rear. Cross drilled disks are for poseurs...

Fred,

Thank you for the healthy dose of common sense. It is just what I needed.

I'm getting 2 front rotors by Brembo, from Tirerack, $250 shipped. I bought Brembo for my Honda Odyssey 2 years ago and I've been very pleased with them.

DM

I bought a set of rotors off the internet (eBay, R1 Concepts).

I did not get what I expected, but the customer service that resulted was excellent. I bought cross-drilled and slotted rotors (for no particular reason) that only cost $20 more than the standard rotors. They also came with nickel plating that ought to prevent rust. In additon to the rotors, the price included a set of pads. The rotors and pads covered all four corners of my car.

My expectation was that the rotors come to me true and ready to install. What I got caused immediate shaking under braking -- the long-story-short is that the rotors were not true, they were warped. I complained to the supplier, and they sent a new set for free. They were not true either.

I took the new rotors to a machine shop and had them trued (machined straight) for $30, and went home and installed them. The brakes work wonderfully. No shaking or screaching. Just reliable stops when the demand is made. I have absolutely no hesitation to suggest you shop eBay, specifically R1 Concepts. BUT, you have to take the rotors they ship to a machine shop to have them trued. (My local Kragen will turn a rotor for $10 or $15 each, but they can not turn rotors that are slotted and drilled.)

I forget the price I paid, but it seems that it was in the range of about $150 for all four rotors and the pads. Then I spent another $30 or so at the machine shop.

Why are brake discs called rotors? for one they dont rotate....

always wonderd this

I'd like to point out that a brake rotor does rotate around the spindle/axle/hub, and it rotates past the brake calipers that house the brake pads.

it was just a sudden brain loss moment, i have changed them before so i knew that, i must have been thinking about something else, that didnt rotate while thinking about a brake disk.

Huh? Of course they bloody well rotate otherwise your wheels don't go around. They only stop rotating when your brake pads stop them (hopefully).

What are you saying, that you overloaded your brain cell?

Your brake disks don't rotate? Mine certainly do. They rotate with the wheel.

You talking about just today, or the last year or so? :-)

When one's brain farts like that, it's best just to do what you did and say so. The people who try to make a hoo-ha about it reveal more about themselves than they will ever know.

Anyone stupid-enough to be a top-poster doesn't have much brain to drain.

QED.

So you bought cross-drilled and slotted rotors. Then you had them machined true. Where did you have them machined? Obviously not at your local Kragen. I'm confused.

It's a showing of age --- a "Senior Moment"

Sorry.

I had to take them to a machine shop and get them turned on a flywheel grinder. Normally, rotors are turned on a lathe, but the slots and holes cause the cutting tool to bounce, so I had to get them ground flat (true) with a grinder that turned the rotors on a turntable while polishing them with a spinning grindstone at the same time.

Just one more in a long list of reasons *not* to get cross drilled or slotted rotors.

I buy rotors that are true out of the box. Saves on trips to the machinist.

As true as that is, I did score a second set of rotors for free that are in perfect condition after I had them turned too.

I don't get why the seller didn't turn the parts before he shipped them; it only takes a few minutes, and he spent more on free shipping and the free parts than the minor machine work would have costed.