Front Brake Discs

I can't find ventilated front brake discs for a 3.0CSI for a reasonable amount in the UK, W&N Euro 150 each, BMW £120 each, Brembo £340 for a pair. Someone stated that a disc from a newer car could be fitted, probably an E12, but needed to be machined down in diameter.
Can anyone say which model car I should buy discs for eg E12 525 year 1978?? I have found a place to machine them down for me for approx £10 each, but I need to know what is best to start with.

Another route is to try to fit larger diameter discs and calipers, has anyone done that for a reasonable cost, and was it much better? If so what did they use? I am not up for a £1,000 kit to fit race brakes.

Thanks
C

Not sure if you can order these from your location, but I've got these on my car and they are fine. $25/ea:

https://www.rockauto.com/catalog/moreinfo.php?pk=4378764&cc=1011070

Thank you, I can order these and the shipping is 3 times the value of the product, however net result is an acceptable price. All the items seem too cheap, bearings, pads, springs etc. Should this concern me, or are copy parts cheap in the US?
Thanks
C

I've been buying parts through RockAuto for all of my vintage cars for years. They certainly don't carry everything, but what they do carry comes from the same sources a lot of the parts houses use. These are Centric rotors. I've got Centric calipers on my '66 Volvo 1800S. Never had a problem with any of it.

They seem to be kind of like the Amazon of auto parts. Same stuff other places offer, but cheaper because of the volume they do.

-Scott

sreams said:

These are Centrix rotors. I've got Centrix calipers on my '66 Volvo 1800S. Never had a problem with any of it.
They seem to be kind of like the Amazon of auto parts. Same stuff other places offer, but cheaper because of the volume they do.-Scott

Click to expand...

Centrix is not Zimmerman, or OEM BMW. The BMW rotors are individually balanced when produced by Zimmerman for BMW. Centrix are cheaper, not because of volume. Think about it, who would sell more BMW rotors? BMW, major/traditional BMW parts suppliers, or Rock Auto? Don't get me wrong, Rock is a good place if you know what to shop for, but Centrix are cheaper because they are made in China.

If someone can show that they are actually flawed in some way or of lesser quality, I'd agree... But to simply assume that they are inferior doesn't seem objective.

Case in point... Carl Nelson sells ball joints for BMW 2002s. The site mentions that you might find cheaper ones elsewhere, but the Moog brand he offers is of higher quality. The cheapest 2002 ball joint on RockAuto is made by none other than Moog, and is less than half the price. To assume that RockAuto = inferior is not accurate, especially when what is being offered is the exact same thing.

-Scott

sreams said:

If someone can show that they are actually flawed in some way or of lesser quality, I'd agree... But to simply assume that they are inferior doesn't seem objective. Case in point... Carl Nelson sells ball joints for BMW 2002s. The site mentions that you might find cheaper ones elsewhere, but the Moog brand he offers is of higher quality. The cheapest 2002 ball joint on RockAuto is made by none other than Moog, and is less than half the price. To assume that RockAuto = inferior is not accurate, especially when what is being offered is the exact same thing. -Scott

Click to expand...

Thats fine, sorry you took my post as something personal.
Centrex is still not Zimmerman, but Moog IS Moog.
If you want to get your panties in a bunch thats your affair,
but go back and read the post (try to be "accurate" in your reading)
and you'll see that I shop with Rock also. Probably far more often than you!
You are the one who broached the term "inferior" ...

You also use that discount supplier to make a backhanded slam of Carl...really ****ty form by-the-way, whether you asked or not!

-30-

dp said:

Thats fine, sorry you took my post as something personal.
Centrex is still not Zimmerman, but Moog IS Moog.
If you want to get your panties in a bunch thats your affair,
but go back and read the post (try to be "accurate" in your reading)
and you'll see that I shop with Rock also. Probably far more often than you!
You are the one who broached the term "inferior" ...

You also use that discount supplier to make a backhanded slam of Carl...really ****ty form by-the-way, whether you asked or not!

-30-

Click to expand...

Not taking anything personally. You may have misinterpreted the tone of my post. And that certainly was not a "slam" of Carl. He is absolutely correct in stating that other sources sell ball joints that are likely of lesser quality than the Moog ones. I am simply pointing out that Rock Auto often offers parts that are of equal quality to the best sources, and typically at a lower price due to their volume advantage. To point out that one source offers a quality part at a lower price than another source does not equate to slamming anyone, especially when one of those sources (Carl) is so valuable for his expertise.

All I'm saying is that no rotor is better than any other unless it can be shown otherwise. Zimmerman may individually balance the rotors they make, but is there evidence that Centric rotors are out of balance? Are they more prone to cracking? (I'm certainly open to hearing that they are, if that is the case). The real question is, in what measurable/practical way is a Centric rotor not a Zimmerman rotor? Isn't that a fair question?

-Scott

Amusing side note to this discussion.
I bought a center bearing from BMW at their dealership in my hometown.
On the box printed- Made in Taiwan........
It was so misshaped it wouldn't fit in the car.
Bosch spark plugs made in Russia, India, Brazil.
The market is tiny now for our parts.

My windscreen, supplied by BMW as a genuine part, made in Turkey, and didn't fit.

The point is, that more often than not the older low volume parts get shoved further and further down the food chain as the demand for these parts lowers, the down side of this is that the quality CAN and DOES suffer.

Just the joys of owning a classic car!