Can 40 tires be replaced with 45?

[SanLila]

Yes, but the sidewall thickness of the tire will increase. Here are the relevant details: 1. Check for surface cracks: Vehicle tires are generally recommended to be replaced every 50,000 to 80,000 kilometers. As long as there are no obvious cracks or signs of aging on the tire surface, you can check the distance between the wear indicators in the main tread grooves and the wear layer. There are also triangular wear indicators on the crown of the tire. If the wear level is almost flush with the wear indicators in the tread grooves or the wear indicators on the crown, it means the tires need to be replaced. 2. Choose durable tires: If you want tires with better durability and handling, consider Pirelli, Goodyear, or Bridgestone. For tires with better overall performance, consider Continental or Michelin. Continental and Michelin use silica additives, which provide better comfort and noise reduction.

[McEmilio]

I think changing the tire aspect ratio from 40 to 45 is possible, but it depends on your specific vehicle. The aspect ratio refers to the ratio of the tire's height to its width. Increasing it from 40 to 45 will make the tire sidewall taller and slightly increase the diameter. Comfort usually improves due to better cushioning, reducing bumps on rough roads. However, handling performance may decline, with more body roll during turns and slower response. More importantly, the speedometer will become inaccurate—larger tires rotate slower, making the actual speed about 5% faster than displayed, which could lead to speeding tickets or accidents. It may also affect fuel efficiency due to increased rolling resistance. Additionally, you need to check wheel compatibility to avoid rubbing against the body. My advice is to calculate whether the diameter change stays within the safe 3% range. It's best to consult the vehicle manual or a professional shop for testing and installation. Ensure electronic systems like ABS function properly to avoid potential hazards affecting driving safety.

[ColinFitz]

As an average car owner, I believe changing tire size requires careful consideration. After switching from 40 to 45, the ride comfort improved significantly, especially reducing bumpiness during long trips and alleviating driving fatigue. However, handling performance does take a hit – when I previously tried higher aspect ratio tires, braking distance increased slightly, steering felt less precise, and hydroplaning risk rose in wet conditions. The speedometer discrepancy is even more troublesome, as actual speed exceeds the displayed value, potentially leading to speeding tickets if unnoticed. Additionally, tire lifespan may decrease while fuel consumption and maintenance costs could rise. I recommend test-fitting just one wheel first to experience urban driving effects. Don't prioritize affordability or aesthetics over safety. Have an experienced mechanic verify wheel compatibility and body clearances to prevent post-modification issues. Ultimately, weigh all factors to select the size that best suits your driving habits.

[AdrielRose]

During vehicle repairs, I would remind owners that changing tire sizes is no trivial matter. Increasing from 40 to 45 profile means larger diameter that may cause insufficient installation space, fender rubbing, and compromised brake cooling. Speed deviation exceeding 5% could interfere with safety systems like abnormal ABS operation. Wheel rim compatibility must be verified - significant specification differences may even require suspension adjustments. Always consult the manufacturer's manual to ensure replacement dimensions fall within permitted ranges. Never make arbitrary decisions as improper sizing may lead to accidents and higher repair costs.