Brake rotors - life expectancy

Hi all,

Okay, I'm relatively new to BMW ownership but over the 3 or 4 months I've been listening in on this group I have read a number of posts concerning brake discs (rotors not pads) wearing out in 50/60k miles. Is this typical, or am I picking up on something that might not really be the norm? I'm talking BMW models generally, of course.

To put this in perspective, my daily use vehicle is a 1996 LR Discovery which has 150k+ miles on the clock and which I've owned from new. The rear rotors are the originals and the fronts have been replaced once (under warranty) due to hairline cracking. This vehicle spends quite a bit of it's time off-tarmac - typically 15 miles per day, 3 or 4 days a week - because of my job and the brakes are, therefore, subjected to much more abuse than a normal road car. During an off-tarmac foray the brakes are often covered/submerged in muddy gloop but despite this even the pads last 45/50k.

I understand that compared to the Discovery (even with it's 3.9litre V8 engine) just about any BMW is a "performance" car but the LR is over 2 tonnes so stopping from almost any speed in a hurry needs considerable braking power.

I'd appreciate any comments from the members of this group on this subject.

Reply to
SteveG
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Yes, this is somewhat typical, but of course depends on one's driving habits and how you use your brakes. General rule of thumb is that

The performance design of the BMW brakes is such that the rotors wear out rather quickly. You could put some harder aftermarket rotors and softer aftermarket pads, but then you would probably not get the same braking performance.

By the way, rotors are cheap (~$75 US per corner) and easy to replace, especially if taken on at the same time as the pads.

Reply to
Malt_Hound

????

You are saying that rotors must be replaced with each brake job, but clearly most of us can go at least two brake jobs before changing rotors. Obviously, the life of a rotor is dependent upon on how hard one goes around mashing on the pedals, but careful and reasonable drivers can easily get upwards of two pad changes out of a rotor.

Reply to
Jeff Strickland

50/60k sounds about right. But they only cost about 20-50 GBP a set depending on model and are easy to change. Unless you have the local $tealer fit them of course......
Reply to
John Burns

Yes - the fronts are likely to only last for two sets of pads.

However, OEM discs from Eurocarparts are pretty cheap and an easy DIY fit. Since they have wheel bolts rather than studs, and the disc goes on the outside of the hub, they don't seize in place. So an easy half day's work to replace the lot - front and back.

Reply to
Dave Plowman (News)

I would be amazed if I got that kind of life out of my iX's rotors lol. I replace them approximately every 35 to 40k miles.

I once had a Grand Am company car, I burnt those rotors up in 25k.

-Russ.

Reply to
Somebody.

Maybe, but off road driving requires gentle use of the brakes?

Reply to
Dave Plowman (News)

As a general rule of thumb, rotors will last through two sets of pads. Your mileage may vary.

Reply to
Jeff Strickland

Oh yes, absolutely ... very gentle and judicious use of the brakes when in the soft stuff. It's not the actual use of the brakes when off-tarmac (note I don't say off-road because all of the tracks I drive are technically roads) but the abrasive nature of the clagg that envelopes the brakes whilst driving along. This acts like a very wet grinding paste ...

Reply to
SteveG

I doubt that muddy paste is any more abrasive than the semi-metallic compounds they use in modern brake pads. Probably less so by a good margin. Sometimes it just isn't all that intuitive... ;-)

Reply to
Malt_Hound

If you include 3 hours of 'Miller time' after the actual 1 hour job ...

-- C.R. Krieger (BT, DT)

Reply to
C.R. Krieger

Well, Dave's in the UK so it might be Bass's Ale or a local pub brew... rather than piss Miller (or Bud/whatever).

Floyd

Reply to
fbloogyudsr

;-)

I haven't got the 6 car fully equipped garage/workshop you guys seem to have. So include the time taken to get the jacks from the cellar to the road, and tidy up afterwards.

Another smiley. ;-)

Reply to
Dave Plowman (News)

It's a euphemism. We *use* Warsteiner or Sprecher or some other reputable brew if the opportunity presents. OTOH, Miller *was* Bobby Rahal's sponsor and they're a 'hometown' (Milwaukee) operation, so I gotta give 'em some credit for that once in awhile - at least if there's nothing good on tap.

*BUD*? Pffft! That's Earnhardt piss!

-- C.R. (Who hardly ever even quaffs a beer.)

Reply to
C.R. Krieger

How 'bout a floor jack and some fairly level (and firm!) gravel in the driveway? That's what I use.

-- C.R. (Who hardly ever even quaffs a beer.)

Reply to
C.R. Krieger

CLARIFICATION It's an easy half-day, not a half day, easy.

The hard part is setting the car on jack stands and taking the tires off.

Reply to
J Strickland

So you can replace discs and pads front and back and adjust the handbrake properly in one hour?

Respect. ;-)

Reply to
Dave Plowman (News)

There is no spec given for this. There are minimum dimensions that must be observed, and the M3 (E36) rotors have a specific admonition against turning the rotors -- because the M3 has the specific admonition and the other models do not, it seems to me that it might be appropriate is some cases to turn rotors on the other E36 models beside the M3, but one must remain with a minimum thickness that exceeds the number stamped on the rotor. So, turning a rotor might be okay IF the result is a rotor that is thicker than the min. specification -- as a practical matter, I don't see how a rotor can be turned AND retain a thickness that is greater than the minumum.

The life of the brake pads is a matter of driving habits/environment, and the life of the rotors is a matter of the life of the pads. Again, as a practical matter, most rotors will last through two sets of brakes. Rear pads will last through two sets of front pads, so rear rotors need to be replaced every fourth brake job, and front rotors need to be replaced every other brake job.

Obviously, your mileage may vary, but as a general guideline, I think these numbers should work out pretty well.

Reply to
Jeff Strickland

I'd like to say a big thanks to everyone that responded to my original post. I'm still a little amazed that BMW use rotor materials that wear out so quickly and (even more amazingly) that owners appear to accept that.

Guess I'm just going to have to come to terms with it as a consequence of driving an otherwise wonderful car ... or just brake less :-)

Reply to
SteveG

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