How reliable is this fitment answer?

Confidence: Confirmed (3 of 3). Backed by a manufacturer document, or two or more independent sources agree on a specific checkable fact. Based on 2 cited source(s), last verified 2026-10-26.

What is the factory spec for the E46 factory brake rotor sizes (325i, 330i, M3) on a BMW 3 Series (E46, 1999-2006)?

Q: What is the factory spec for the E46 factory brake rotor sizes (325i, 330i, M3) on a BMW 3 Series (E46, 1999-2006)?

Factory specification. BMW's 2004 brochure gives vented discs of 11.8 in front / 11.6 in rear on the 325i and xi, and 12.8 / 12.6 in on the 330i and xi. BMW's M3 release gives the 330's discs as 325 mm front / 320 mm rear and says the M3 uses thicker rotors (28 mm front vs 22 mm, 20 mm rear vs 19 mm) with 328 mm rears. Factory spec only; it does not mean the parts swap. The 325i figures are confirmed for 2004 only and the 330/M3 figures at the M3's 2001 launch; 1999-2000 323i/328i brakes are not covered.

Added 2026-10-26 · Updated 2026-10-26

Short answer: Factory specification Confirmed

Verdict:Factory spec Confirmed confidence (3 of 3) · 2 sources

Factory specification: BMW's 2004 brochure gives vented discs of 11.8 in front / 11.6 in rear on the 325i and xi, and 12.8 / 12.6 in on the 330i and xi.

Years: 2001-2004 · Applies to: 325i/325xi and 330i/330xi (2004 brochure); 330 and M3 (2001 M3 release); 1999-2000 323i/328i not covered · 2 sources · Last verified 2026-10-26

Safety-critical part. This claim comes from community or vendor sources, not the vehicle or part manufacturer, so its confidence is capped at "Reported". Have the work done or checked by a qualified professional and confirm part numbers with the manufacturer.

Part	E46 factory brake rotor sizes (325i, 330i, M3)
Vehicle	BMW 3 Series (E46, 1999-2006)
Years	2001-2004
Trim / condition	325i/325xi and 330i/330xi (2004 brochure); 330 and M3 (2001 M3 release); 1999-2000 323i/328i not covered
Verdict	Factory spec Specification
Confidence	Confirmed 3 of 3 — Backed by a manufacturer document, or two or more independent sources agree on a specific checkable fact.
Last verified	2026-10-26 (date the cited sources were last read)

Details

BMW's 2004 brochure gives vented discs of 11.8 in front / 11.6 in rear on the 325i and xi, and 12.8 / 12.6 in on the 330i and xi. BMW's M3 release gives the 330's discs as 325 mm front / 320 mm rear and says the M3 uses thicker rotors (28 mm front vs 22 mm, 20 mm rear vs 19 mm) with 328 mm rears. Factory spec only; it does not mean the parts swap. The 325i figures are confirmed for 2004 only and the 330/M3 figures at the M3's 2001 launch; 1999-2000 323i/328i brakes are not covered.

Specs

325i 325xi: 300 mm front / about 294 mm rear (11.8 / 11.6 in), vented
330i 330xi: 325 mm front / 320 mm rear (12.8 / 12.6 in), vented
m3: 325 x 28 mm front / 328 x 20 mm rear; 330 rotors are 22 mm front / 19 mm rear thick

Related build entries

Know your factory brake size before swapping E46 brakes

Other brakes fitment for the E46

E46 M3 front brakes (325 x 28 mm rotors, calipers and carriers) — Unclear — details missing Unclear

More for this car

All BMW 3 Series (E46, 1999-2006) fitment answers · E46 common problems
Newsletter archive: past issues with every new and corrected entry

Sources

2004 BMW 3 Series Sedan brochure (specifications and wheel options) — BMW of North America (brochure PDF hosted by autospies.com) (mfr spec; read 2026-10-26; full page read)
2004 sedans: vented discs 11.8 / 11.6 in (325i, 325xi), 12.8 / 12.6 in (330i, 330xi).
The New BMW M3: A Legend Is Reborn (press release, Dec 2000) — BMW of North America (press release PDF hosted by unofficialbmw.com) (mfr spec; read 2026-10-26; full page read)
Dated Dec 1, 2000: 330 discs 325 / 320 mm; M3 328 mm rears; rotors 28 vs 22 mm front, 20 vs 19 mm rear.

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