Q. What is the difference between a staggered and non-staggered tire setup?
A. Model year 1995 M3s came from the factory with a non-staggered setup (all four wheels and tires are the same size), whereas 1996-1999 M3s were fitted with a staggered setup (see wheel and tire sizes below). Some believe this was BMW's way of reducing oversteer to help inexperienced drivers. As you may have guessed, the original non-staggered setup is more balanced and allows the car to rotate or oversteer with less effort. All M3s can run either setup without any problems.
Q. What are the OEM tire and wheel sizes and weights?
A. See table below:
|M Round Spoke||M Contour||M Forged|
|1995||235/40-17 x 7.5 (all)||41 mm||21.3 lb||22.3 lb||19.5 lb|
|M Round Spoke II||M Contour||M Forged|
|1996-1999||225/45-17 x 7.5 (front)||41 mm||21.9 lb||22.3 lb||19.7 lb|
|245/40-17 x 8.5 (rear)||41 mm||22.9 lb||23.4 lb||20.9 lb|
Q. What are the differences between genuine M Forged wheels and replicas?
A. BMW made two versions of the M Forged wheels, an early (for the 1995 M3 Lightweight) silver painted version with 'MOTORSPORT' text and later (1996+) a polished version with no lettering. The more common 1996+ forged wheels included small pockets for the '///M' logo, something no replica includes. Also, be mindful that the replicas are not forged, making them significantly weaker and heavier than the genuine wheel.
Q. Will 16 inch diameter wheels fit on my M3?
A. Generally, most (if not all) 16 inch wheels will not fit due to brake caliper clearance issues. Ronal and ATP do make 16 x 7.5 inch wheels that should fit (verify with your wheel distributor) and may be a worthy option if you intend to drive in the snow. A recommended minus one sizing for tires is 205/55-16.
Q. What are the recommended stock tire pressures?
A. The information located on the driver side door jamb indicates 33 psi front and 36 psi rear for 1995 M3s and 30 psi front and 35 psi rear for 1996-1999 M3s. However, a few psi higher in both front and rear will help better protect your rims from potholes with the minor downside of increased ride harshness. An increase or decrease in front or rear tire pressures will also result in altered vehicle dynamics per Tire Rack at http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=58¤tpage=31.
Q. What is the recommended torque for the lug bolts?
A. The 17 mm lug bolts require 100 Nm (+/- 10 Nm) or 73.8 lb ft (+/- 7.4 lb ft) of torque.
Q. What is the clunking noise coming from the back of my car when going over bumps?
A. The clunk or rattling noise (emanating from either the right or left side, aft of the rear seats) when going over bumps or rough roads is likely caused by a failed shock mount. Replacement of the mount is the only fix, however JT Designs offers a stronger urethane mount that should last considerably longer. For additional information, be sure to visit Ron Stygar's page at http://www.unofficialbmw.com/e36/suspension/e36_replace_rear_shock_bushings.html.