OVERVIEW

The rear axle bar and inner CV upgrade for the 2014+ F80-F83 M3/M4. The Driveshaft Shop developed a set of 300M axle bars along with chromoly inner and outer CV internal components. Using proprietary 1.25″ diameter high-grade 300M bars (stock axle bars are 28 spline), a custom chromoly CV cage and race set, these axles become practically indestructible. The factory outer CV housing is made from a very strong material, so this upgrade is more than enough to handle the 1200 HP rating offered.

This is a send-in service on your own factory axles. DSS tempers and shot-peens the OEM outer and inner housings, installs factory-style metal boot covers on the outer CV (double o-ring sealed), and installs the new chromoly cage/race internals along with 30-spline bars.

SPECS

Proprietary 1.25″ diameter high-grade 300M axle bars
30-spline bars (stock axle bars are 28 spline)
Custom chromoly CV cage and race set
Chromoly inner and outer CV internal components
Factory outer CV housings retained, tempered and shot-peened
Factory-style metal boot covers on the outer CV, double o-ring sealed
Rated to 1200 HP
Warranty: 1 year (The Driveshaft Shop)
Built to order on your cores — call for current lead times

PARTS INCLUDED

Upgrade service only: 300M axle bars, chromoly inner/outer CV internals, cage and race set and metal boot covers installed into your supplied OEM axle housings. Your factory axles are required as cores.

TECH RESOURCES

Additional Parts Required

Your factory OEM axles. This is an upgrade-only service — you must send in your own axles for DSS to assemble the set.
RMA number. Call for lead times and an RMA number before shipping your axles in.
Single-use axle nuts and any damaged OEM boots or hardware should be replaced at reassembly.
Professional installation is recommended.

Installation

The Driveshaft Shop does not publish a downloadable installation guide for this upgrade. Contact Speed Logic or The Driveshaft Shop directly for RMA, lead time and torque guidance.

Notes

**You must send in your axles to have this process done, please call for lead times and an RMA number before sending them in.**
Upgrade service only — no new axle housings are supplied. Confirm model year fitment and current lead times with Speed Logic before ordering.

PART NUMBER

M4R1
DSS SKU: 510415

VEHICLE APPLICATIONS

Make	Model	Chassis	Engine	Years
BMW	M3 Sedan	F80	S55 3.0L Twin-Turbo I6	2014–2018
BMW	M4 Coupe	F82	S55 3.0L Twin-Turbo I6	2014–2018
BMW	M4 Convertible	F83	S55 3.0L Twin-Turbo I6	2014–2018