4.10 Short Ratio Ring and Pinion Set for BMW 188 mm Differential Quicker easier cheaper and with all the benefits of an engine upgrade : the short ratio gear set is without doubt the best modification you can make to your vehicle for all kinds of motorsports (trackdays drifting grip rally etc). The kit includes a 4.10 ratio ring and pinion set which comes as a direct replacement of the OEM final drive gear set of all BMW 188 mm differentials. Most BMWs are equipped with rather long final drive ratios. Changing to a short ratio allows for an increase in wheel torque output (compared to a wider ratio in identical conditions). It offers a similar increase in performance to an engine upgrade and/or a weight reduction allowing your engine to rev quicker without creating any additionnal mechanical stress or wear. Specially designed for intensive use this short ratio gear set is made from forged steel and reinforced with high quality surface treatments (thermal treatments shot peening...) guaranteeing a long lifespan for use on the track and excellent resistance under heavy duty and extreme conditions. This short ratio final drive is compatible with all BMW 188 mm differentials which are most commonly found on 6 cylinder BMWs until the early 2000s. Application List E23 6 cylinders E24 6 cylinders E28 6 cylinders E30 6 cylinders & M3 E30 E34 6 & 8 cylinders (exc. 540i and M5) E36 6 cylinders inc. M3 3.0L (not M3 3.2L) Z3 6 cylinders (inc. Z3 M S50 and S54) Notice : not suitable for type K 188 mm differentials from BMW E46 Notice : not suitable for differentials with OEM ratio < 3 (E36 325 tds 328i)