Size, Offset, & Style
|195/70-14||Wheel: BBS "Basketweave" wheels in the same size and offset were offered on early models.
Tire: The 195/70-14 tire size is widely available in many tread types and performance ratings from many manufacturers.
Fitment: Will fit all non-M5 E28s running stock brakes.
|200/60-390||Wheel & Tire: This is the infamous TRX wheel and tire setup. At the leading edge of tire technology when introduced in the early 1980s, the TRX used a unique bead design which was incompatible with standard designs. To preclude intermixing TRX and non-TRX wheels and tires, the TRXs were given non-standard sizes; 340, 365, 390, and 415mm diameters were offered on many makes and models; the 390mm is equivalent to 15.35". Over twenty years after its introduction, the TRX is considered obsolete, yet new TRX tires (when they can be found) command upwards of $200 each! If you must absolutely have new TRXs, Coker Tire is reproducing them using the original Michelin molds. IMPORTANT: 15" tires CANNOT be safely fitted to 390mm wheels!
Fitment: Will fit all E28s running stock brakes or the common E32/E34 "Big Brake Upgrade."
|225/50-16|| Wheel: One of the most-common upgrade sizes for E28s, with many BMW and aftermarket wheels available.
Tire: The 225/50-16 tire size is widely available in many tread types and performance ratings from many manufacturers.
Fitment: Will fit all E28s running stock brakes or the common E32/E34 "Big Brake Upgrade." Non-M5 E28s might encounter rear fender lip interference with this setup (more on this in the "Fender Rolling or Trimming" section below); M5 rear fender lips are pre-trimmed by the factory.
Size, Offset, & Style
|The 205/70 was fitted to E23s and E24s and will have a minimal effect on speedometer readings. Some 225/60s will fit the wheel (this must be checked against the tire manufacturer's acceptable width range), but will cause the speedometer to read approximately 7% faster, and rear fender lip interference is possible.|
|220/55-390||The speedometer reading will be unaffected, but rear fender lip interference is possible. Due to the aforementioned obsolescence of the TRX design, this is not considered an "upgrade."|
|Spreadsheet Page Title||Description|
|READ THIS FIRST!||So named for good reasons, the "READ THIS FIRST!" page fully explains how to use and interpret the spreadsheet.|
|E28 Wheels Tires||The listing of the wheel & tire combinations. If a combination you're considering isn't listed, you can input the data for it on any line after the first entry, or on the two lines labeled "TEST" at the bottom of the sheet.|
|Size Calculator||Contains formulas for "Plus X" conversions, tire diameter comparisons, wheel offset/backspacing/frontspacing calculations, and metric-to-inch & inch-to-metric conversions. These calculations can be used for most any vehicle, not just an E28.|
|Constants||Values which are used in the calculations in the "E28 Wheels & Tires" sheet.|
|Depending on the available working gap between the tire and fender, a thick wooden dowel or baseball bat is placed between the between the tire and the fender lip at either end. One person guides the dowel/bat and another slowly moves the car forward or backward. Multiple passes might be necessary.||Pros: Maintains fender lip integrity and strength. The quicker of the two methods.
Cons: Imprecise. Can affect fender lip and fender profile and crack paint and detach undercoating. Forms a tight, pinched channel on the inside of the lip which can attract and hold grit, fostering formation of rust. Difficult or impossible to clean or paint/undercoat inside the pinched channel.
|Trimming||A Dremel or die grinder with an abrasive cutoff wheel is used to remove a slice of the inner fender lip at the interference point.
See this diagram for more information on this technique.
|Pros: Maintains fender lip profile. The more precise of the two methods. Does not crack paint or undercoating, and does not leave a grit-attracting pinched channel. Easy to touch up raw edges with paint or undercoating.
Cons: Takes more time. Can burn paint close to cut and affect temper of the metal if not done carefully. Slightly reduced fender lip strength.