What is the tire model of the BMW 325Li?

[VonJace]

BMW 325Li uses Michelin tires with a size of 225/45R18. How to check the tire model: The tire model can generally be found on the sidewall of the tire. For example, 225/50R1798H, where 225 represents the tread width in millimeters; 50 is the aspect ratio, indicating 50%, with most household car tires having an aspect ratio between 30% and 80%. Normally, ordinary sedans should not use tires with an aspect ratio > 75%, while luxury cars and high-performance sports cars are recommended to use tires with an aspect ratio < 60%. Tire classification: Tires are classified by usage, including load-bearing tires, passenger car tires, and mining tires, among others. Load-bearing tires must indicate the ply rating on the sidewall in addition to the size specifications. However, it should be noted that the ply rating of load-bearing tires does not refer to the actual number of layers but rather to the load performance of the tire body made with high-strength material cords, which is equivalent to the number of layers of a tire body made with cotton cords.

[DeGage]

The tire specifications of the BMW 325Li are quite interesting. My car came with a staggered setup from the factory: 225/45 R18 for the front tires and 255/40 R18 for the rear tires. This design increases rear tire width for better traction, making cornering noticeably more stable. However, different model years may switch suppliers—my 2019 model came with Bridgestone Turanzas, while a friend's 2021 model got Goodyear Eagle F1s. When replacing tires, remember to check the alphanumeric markings on the sidewall and choose H or V speed ratings to match the car's performance. Pay extra attention to tire pressure during routine maintenance—the low rear tire aspect ratio makes them prone to punctures and sidewall bulges, and replacing one can be quite costly.

[StGraham]

The tire configuration of the 325Li is quite sophisticated, with standard specifications being 225/45 R18 at the front and 255/40 R18 at the rear. This staggered width design primarily enhances the performance of rear-wheel-drive vehicles, making cornering more agile. The complete tire model, such as 225/45 ZR18, can be seen on the tire sidewall, where 45 represents the aspect ratio, and Z indicates a maximum permitted speed of 240 km/h. When selecting tires, it's essential to check whether the wheel size is 18 or 19 inches, as the sport package version comes with 19-inch tires, changing the model to 255/35 R19. Personally, I recommend performance-oriented tires like Michelin PS4 or Continental MC6, which are particularly suitable for the tuning of the 325Li. Remember to rotate the tires every 30,000 kilometers.

[HazelDella]

The BMW 325Li has two common tire specifications: the standard version uses 225/45 R18 tires front and rear, while the sport version features 225 front and 255 rear 18-inch tires. With an aspect ratio of 40 to 45, these fall into the low-profile tire category, requiring extra caution when crossing speed bumps. Tire width is measured in millimeters, and the last two digits (18) indicate the compatible wheel diameter. When selecting new tires, besides specifications, pay attention to the load index, typically 91 or 95, corresponding to standard load ratings. Factory tires are prone to uneven wear, so it's recommended to perform a wheel alignment check every 10,000 kilometers.

[OLila]

Let's talk about the 325Li tires. The standard configuration features 225mm wide tires with a 45 aspect ratio on both front and rear, all 18 inches in size. However, the sport version specifically increases the rear tire width to 255mm. This differential design is quite common in BMW models, primarily to provide better driving traction for rear-wheel-drive vehicles. The 'R' in the tire model stands for radial construction, which is the standard technology nowadays. From my observation, the original factory often equips them with energy-efficient tires like the Pirelli P7 or Goodyear EfficientGrip. When replacing tires, it's recommended to change the entire set, as a tread depth difference of more than 3mm between front and rear tires can affect the intervention of the ESP system.

[DeMax]

After driving the 325Li for two years, the tires have been my biggest concern. The standard specifications are 225/45 R18 for the front tires and 255/40 R18 for the rear tires. In these numbers, 45 and 40 represent the aspect ratio percentages—the lower the number, the thinner the tire sidewall. Make sure to look for the load index of 91 and the speed rating of Y (up to 300 km/h). Be extra cautious in rainy weather as these wide rear tires are prone to slipping, and remember to check that the tread depth is no less than 3 mm. For winter, it’s advisable to have a set of snow tires ready, as the factory summer tires simply can’t grip on ice. When replacing tires, pay attention to the production date—tires older than two years start to degrade as the rubber ages.