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Crankshaft Pulleys & Harmonic Balancers

Keep your drive belt system in check by replacing your BMW's crankshaft pulleys and harmonic balancers.
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M7 Speed - Corporate Logo
T#:584439
Part#: 53-3M7101-4
In Stock
$ 159.99 USD
Free Shipping
$ 159.99 USD
Free Shipping

M7 Speed 4% Oversize Crankshaft Pulley for MINI Cooper

Unlocking Performance

The M7 Speed 4% oversize crankshaft pulley is your ticket to unlocking the hidden potential of your MINI Cooper. This performance-enhancing pulley is designed to add power, acceleration, and overall performance to your beloved MINI. Here's how it does the trick:

Performance Boost:

  • Safely speeds up your supercharger, delivering a significant "low end" boost and torque.
  • The result? Your MINI Cooper takes off with newfound energy and responsiveness.

Lightweight Advantage:

  • Weighing just 13 ounces, this pulley is a remarkable 88.5% lighter than the factory version.
  • Reduced crankshaft rotational mass equals more horsepower, torque, and improved throttle response.

Advanced Design

The M7 Speed 4% Crank Pulley isn't just about performance; it's also a work of art. Crafted with advanced computer modeling and precision CNC machining, it's a blend of form and function:

Materials:

  • Made in the USA from billet 6061-T6 aerospace-grade aluminum alloy.
  • Features a deep black anodized coating and laser etching for a sleek look.

Precision Machining:

  • Micro V-Belt grooves meet SAE J1459 specifications to minimize belt slippage, especially at maximum boost.

Optimal Fit:

Use it in conjunction with the M7 Speed 16% Supercharger Technology Pulley for peak performance in MINI tuning.

Reliable Performance

From the factory, MINI lacks a positive drive key on the crankshaft snout to drive the lower pulley. Most aftermarket pulleys are slip-fit and rely on the bolt to prevent slippage. The M7 Speed crank pulley is engineered differently:

Interference Fit:

The pulley is interference-fit onto the crankshaft, ensuring zero slippage even at high RPMs.

Features at a Glance:

  • Super Lightweight: Only 13 ounces (0.3 kg)
  • Sheds 6.2 lbs (2.8 kg) compared to stock
  • Achieves perfect balance through a symmetric design and precision machining
  • Includes a high-quality ARP Racing bolt and precision ground flat washer
  • Installation is a breeze

Unleash Your MINI's Potential

Proudly made in the USA, the M7 Speed 4% Oversize Crankshaft Pulley is the upgrade your MINI Cooper deserves. Unleash its hidden power and enjoy a new level of performance, reliability, and overall driving pleasure. Get ready to experience the difference.

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Genuine BMW Motorsport - Corporate Logo
T#:396369
Part#: 12311311449KT
Ships on Sep 15, 2026
$ 1,696.99 USD
Free Shipping on orders $49 and up

Group A racecars were the top of their class in both touring car and rally racing. Heavily modified and extremely fast these cars set out to demonstrate the best of what a manufacturer could do on the racetrack. It was the predecessor to the current DTM class racing and set a standard for many other divisions of motorsport to follow.  

One of the weaker points of the S14 engine, when speaking from a racing standpoint is the belt drive system. While fine for a street going car, a V-belt is not suitable for high RPM applications. On the track, most of your time will be spent in the higher rev range which puts extreme amounts of stress on the factory setup. BMW realised this and came up with a solution that involved doing away with the V belt system and using a 6 rib serpentine style instead.

Extremely resistant to slippage and failure this design holds up much better the abuse of track duty and won't leave you stranded and waiting for tow back to the pit. Additionally, this kit does not accommodate and a/c compressor and the alternator and waterpump are underdriven by way of slightly larger pulleys. Combined, this puts less of a load on the crankshaft which leads to more efficient power delivery to the ground. If you track you E30 M3, this is an essential upgrade and until now was extremely difficult to source. Do not skip this pivotal step in your engine build or overhaul and get a leg up on the competition the Group A way.
Please note this kit is special order and in non-returnable

Features:

  • Kit replaces all engine pulleys and crank damper
  • Includes 6 rib serpentine belt
  • Underdriven waterpump and alternator pulleys
  • Recommended for off road and racing use only 

This kit fits the following BMWs:
1986-1992 BMW M3 All 
 

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