ENDLESS REAR INCH UP KIT SYSTEM INCH UP KIT REAR FOR AUDI RS3 (8V) SEDAN EEZ8YRS38V

 

ENDLESS REAR INCH UP KIT SYSTEM INCH UP KIT REAR FOR AUDI RS3 (8V) SEDAN EEZ8YRS38V

The ENDLESS Rear Inch-Up Kit System, part number EEZ8YRS38V, is essentially a rear-axle brake upgrade that increases rotor size while retaining the factory rear caliper architecture. 

ENDLESS lists the RS3 (8V) Sedan as an application for its rear Inch-Up system, with a 332 × 22 mm two-piece rotor. 

🧠 Technical breakdown

Area	Stock concept	ENDLESS Rear Inch-Up
Position	Rear	Rear
Rotor	OEM-size	332 x 22 mm
Construction	OEM	2-piece performance rotor
Caliper	Factory rear caliper retained	Factory caliper retained
Main upgrade	Standard thermal capacity	Greater thermal capacity & consistency
Unsprung mass	OEM baseline	Optimized 2-piece construction
Purpose	Road/OEM balance	Fast road + track-oriented braking

The clever engineering is that this isn’t simply “put a bigger brake on the back.” The kit uses an adapter arrangement to position the original rear caliper farther outward, allowing it to work with the larger rotor. 

This preserves the factory parking-brake arrangement while increasing the disc’s effective thermal capacity. 

🔥 Why the 332 mm rotor matters

The important physics is:

Brake torque ≈ caliper clamping force × effective rotor radius

Increasing rotor diameter increases the effective braking radius, so the same caliper force can generate more braking torque.

But the bigger advantage on a hard-driven RS3 is heat management.

ENDLESS’s own RS3 replacement-disc testing shows its two-piece 370 × 34 mm front disc can produce substantially different temperature behavior versus the OEM disc, illustrating why ENDLESS focuses heavily on rotor construction and cooling. 

The rear Inch-Up therefore complements a serious front brake upgrade rather than trying to turn the rear axle into the dominant braking axle.

⚙️ Why retain the OEM rear caliper?

This is actually a very intelligent approach for an AWD performance car like the RS3.

The rear brakes have several jobs:

Deceleration → stability → ABS control → electronic brake-force management → parking brake

Making the rear caliper dramatically larger can disturb the carefully engineered front/rear brake balance.

ENDLESS instead increases the rotor’s mechanical leverage and thermal capacity while keeping the factory rear caliper architecture.

That gives you:

larger rotor → greater thermal mass → improved heat resistance → more consistent braking → less risk of rear-brake imbalance.

🏁 Best configuration

For an aggressively driven RS3 8V, the interesting ENDLESS combination is:

Front: Racing MONO6 + 380 × 34 mm 2-piece rotor
Rear: Inch-Up + 332 × 22 mm 2-piece rotor

ENDLESS’s vehicle catalogue specifically lists this combination for the RS3 8V Sedan. 

The front Racing MONO6 uses a forged monoblock caliper and is designed around a 380 × 34 mm two-piece rotor for this RS3 application. 

🏆 My assessment

EEZ8YRS38V is a very sophisticated upgrade rather than a conventional BBK.

Street: ⭐⭐⭐⭐⭐
Fast road: ⭐⭐⭐⭐⭐
Track: ⭐⭐⭐⭐⭐
Thermal management: ⭐⭐⭐⭐⭐
OEM integration: ⭐⭐⭐⭐⭐
Rear brake balance: ⭐⭐⭐⭐⭐

The biggest attraction is engineering efficiency: rather than replacing everything, ENDLESS upgrades the part that most directly improves rear-axle thermal capacity—the rotor—while maintaining the factory caliper system.

For an RS3 8V quattro, I’d regard this as particularly attractive when paired with a serious 380 mm front ENDLESS system, rather than installing the rear kit alone.

ENDLESS REAR INCH UP KIT SYSTEM INCH UP KIT REAR FOR AUDI RS3 (8V) SEDAN EEZ8YRS38V