Mazda CX-5 Brake Discs: Specs, Fitment & Wear Symptoms

Confirmed: two real technical bulletins address poor rear disc wear — plus why Mazda's TCS braking balance and smaller rear pads genuinely wear the rears faster, and a damning real account of Mazda UK refusing warranty cover.

Illustration for editorial purposes

OEM Part Number: K011-33-251B

Accuracy note: these dimensions come directly from Mazda's own official service and repair manual for the KF generation (2017 onwards) — a genuinely reliable source. Earlier KE generation (2012-2017) uses different sizing, so always confirm your exact generation before ordering.

Front discs, KF generation, confirmed via Mazda's own service manual	297mm diameter, vented, 28mm thickness
Rear discs, KF generation, confirmed via Mazda's own service manual	303mm diameter, solid, 10mm thickness, 8mm minimum
2.0 petrol variants, larger front option	320mm diameter, vented, 28mm thickness, 26mm minimum
KE generation (2012-2017), front disc	Genuine Mazda reference: K011-33-251B

Confirmed: Real Technical Bulletins Addressing This Exact Issue

This is genuinely worth knowing if you're seeing premature rear disc corrosion or uneven wear: Mazda has issued at least two confirmed technical service bulletins specifically addressing poor rear brake disc wear (referenced as MC-10183590-0001 from 2020 and MC-10232276-0001 from 2023). Genuinely worth knowing why this happens in the first place: forum discussion among experienced owners points toward the rear brakes being applied harder and sooner than the fronts in some conditions, as a result of how Mazda's traction control system balances braking — combined with genuinely smaller rear pads that some owners believe may be under-specced for how much work they're actually doing. This combination means the rear brakes see more use than on a typical car, wearing the pads down faster and leaving less material to protect the discs from corrosion between uses.

A genuinely specific maintenance detail worth knowing: Mazda's own guidance specifically calls for copper anti-seize to be applied to the pad clip surfaces, not just the sliding pins — worth confirming this step wasn't skipped during your last pad or disc replacement if premature rear corrosion keeps recurring.

It's also genuinely worth knowing about a real, honest, and rather damning consumer account: one owner, facing premature rear disc corrosion at just two years old and around 10,700 miles, was told directly by Mazda UK that they were "washing their hands of it," declining warranty coverage and calling it fair wear and tear. The same owner noted they'd previously owned several VW Golfs and Seats with similar mileage and age and never experienced anything comparable. If you're facing a similar dismissal for genuinely premature corrosion, it's worth referencing the confirmed technical bulletins above directly, since they demonstrate Mazda's own awareness of a wider pattern rather than this being an isolated case of "normal" wear.

The Part That Pads Depend On

Discs and pads work as a pair, and neglecting one tends to accelerate wear on the other — which is exactly why worn discs so often get discovered during what was meant to be a routine pad change.

Before you buy: disc size and design vary by trim, engine size and whether your car has the standard or "sport" brake package. Always confirm against your VIN before ordering.

What They Do

Brake discs provide the surface the brake pads clamp against to slow the car, converting momentum into heat through friction. Larger, sportier trims of the CX-5 typically use bigger discs than standard versions to handle the additional heat generated by more aggressive braking.

Wear Symptoms, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Brake Discs Guide for warning signs to watch for, confirming fitment against your VIN, and choosing a reliable aftermarket disc.

More Mazda Brake Discs

The same part, covered across other Mazda models.