Lexus IS Brake Discs: Specs, Fitment & Wear Symptoms
A genuinely alarming, honest account: brand new discs had the exact same vibration return within weeks — plus a genuine finding that front hub runout, not the disc itself, can be the actual persistent cause.
Illustration for editorial purposes
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OEM Part Number: 43512-30310 (genuine front disc — confirm via VIN) — aftermarket front discs Brembo 09.A717.11 / TRW DF4855S
| Front brake discs (aftermarket) | Brembo 09.A717.11 (296 x 28 mm, vented, 5 holes, coated, high-carbon, minimum thickness 25 mm, tightening torque 103 Nm); febi bilstein 108498 (296 x 28 mm, vented, 5 holes, coated, minimum thickness 26 mm); TRW DF4855S (334 x 30 mm, vented, 5 holes, painted, high-carbon, left front); TRW DF4856S (334 x 30 mm, vented, 5 holes, painted, high-carbon, right front, minimum thickness 27 mm); Zimmermann 590.2822.52 (334 x 30 mm, vented, drilled, 5 holes, coated, high-carbon, left front, pairs with 590.2823.52, minimum thickness 27 mm, KBA 60872) |
|---|---|
| Disc sizes & variants | Two front sizes, 296 x 28 mm and 334 x 30 mm. The 334 mm discs are handed (separate left and right part numbers) and belong to the larger-brake specification, typically the F Sport and higher-output 300h/350 cars; the 296 mm disc is the standard fitment for the 300h and 250 models. |
| Genuine (OE) numbers quoted | 43512-30310 (genuine front disc number for this model — confirm via VIN, as several disc sizes exist) |
| Fitment notes | Check which size is fitted before ordering, as the 334 mm discs are sold as left and right parts and will not interchange with 296 mm callipers. Bolt circle 5 x 114.3 mm. |
Lexus IS Brake Discs: The Part That Pads Depend On
On the Lexus IS, 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.
Lexus IS Brake Discs: Watch: Replacing It
Third-gen IS250, discs and pads; the guide does not say front-only.
Lexus IS Brake Discs: 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 IS typically use bigger discs than standard versions to handle the additional heat generated by more aggressive braking.
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A Genuinely Alarming, Honest Real Account Worth Knowing — Lexus IS Brake Discs
If a vibration under braking has survived multiple rotor replacements, this is genuinely worth knowing: documented cases describe brand new discs and pads fitted to resolve throbbing under braking, only for the exact same vibration to return within a matter of weeks, on a car with only a couple of thousand miles covered since the repair. It's genuinely worth knowing that repeatedly replacing the same rotors isn't guaranteed to resolve the fault if the actual root cause lies elsewhere.
It's also genuinely worth knowing an honest account worth bearing in mind: if a fresh replacement disc shows the identical fault from the very start, straight out of the box, the disc itself likely isn't the actual root cause. It's also worth cleaning the mating faces between the hub, disc, and wheel thoroughly before assuming a disc is warped, since accumulated dirt or corrosion at these contact points can itself cause a genuine vibration.
Lexus IS Brake Discs: 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 Lexus Brake Discs
The same part, covered across other Lexus models.