Tire Size 285/75r16 vs 285/70r16
Are you considering swapping out your trusty 285/75r16 tires for a slightly smaller 285/70r16 set? While the width stays the same at a beefy 11.22 inches, the 70 aspect ratio means a bit less sidewall height compared to the 75 series.
But will this swap work for your ride, or leave you wishing you stuck with the original rubber? Let’s dive in and see how these two tire sizes stack up.
- The overall diameter decreases by 1.12 inches (28.5 mm), a 3.4% reduction
- The tire width remains the same at 11.22 inches (285 mm)
- The sidewall height decreases by 0.56 inches (14.25 mm), a 6.7% reduction
- The shorter sidewall may result in a slightly firmer ride and reduced off-road capability
- The overall look of the vehicle may be altered due to the smaller tire size
285/75r16 vs 285/70r16
The key difference between 285/75r16 and 285/70r16 tires comes down to the sidewall height.
Fitment Guide
Before you bust out the tire iron, be aware that a safe replacement tire should stay within 3% of your current tire’s total diameter.
In this case, the 285/70r16 measures 31.71 inches across, a full 3.4% smaller than the 32.83 inch diameter of the 285/75r16. That’s enough of a difference to give many mechanics pause, as the size change could lead to rubbing and clearance issues.
On-Road Impact
So how will this size swap impact your on-road driving experience? Here are a few factors to consider:
- Speedometer Accuracy: That 3.4% reduction in diameter translates to your tires rotating about 21 more times per mile. Your speedo won’t automatically adjust for this, so it will overestimate your speed by roughly the same percentage. When it reads 60 mph, you’ll actually be going 58 mph. Not a huge difference, but worth noting.
- Ride Comfort: The shorter sidewall of the 70 series means a slightly firmer ride over bumps and potholes. You may feel more of the road, especially if your vehicle doesn’t have a cushy suspension. The tradeoff is typically better handling responsiveness.
- Gas Mileage: The 285/70r16 has nearly 3.5 inches less circumference per revolution. That means the engine has to work a touch harder to maintain the same speed, which could impact fuel efficiency. However, the difference is likely negligible in real world conditions.
- Aesthetics: Some drivers prefer the look of a slightly larger tire with more sidewall. Stepping down to a 70 series may give your vehicle a more low-profile appearance, which comes down to personal taste.
Off-Road Impact
If you’re an off-road enthusiast, the gap between these two sizes is worth a closer look:
- Ground Clearance: The taller 75 series sidewall provides over half an inch of extra height, which helps avoid scrapes and dings from rocks and obstacles. Depending on your usage, this could be a significant factor.
- Durability: A larger sidewall acts as a buffer and allows the tire to flex and conform to uneven terrain. The 70 series, with its shorter and stiffer sidewall, may be more susceptible to cuts, punctures, and impact damage when venturing off the beaten path.
- Traction: In general, a larger contact patch – the amount of rubber meeting the ground – provides better traction. The 70 series, being slightly shorter, may give up a bit of grip in loose or sloppy conditions. However, specific tread design can also play a big role here.
What is the Difference Between 285/75r16 and 285/70r16?
The main difference between 285/75r16 and 285/70r16 tires lies in the aspect ratio, which affects the sidewall height and overall diameter.
The 285/75r16 tire has a taller sidewall (8.42 inches) and a larger overall diameter (32.83 inches) compared to the 285/70r16 tire, which has a shorter sidewall (7.85 inches) and a smaller overall diameter (31.71 inches).
Can I Use 285/70r16 Instead of 285/75r16?
Using a 285/70r16 tire instead of a 285/75r16 is not recommended, as the difference in overall diameter exceeds the generally accepted 3% threshold. The 285/70r16 tire is 3.4% smaller in diameter than the 285/75r16.
How Much Taller Is a 285/75r16 Tire Than a 285/70r16?
A 285/75r16 tire is 1.12 inches (28.5 mm) taller than a 285/70r16 tire. This difference in height is due to the larger sidewall of the 285/75r16 tire, which measures 8.42 inches (213.75 mm) compared to the 7.85-inch (199.5 mm) sidewall of the 285/70r16 tire.
The overall diameter of the 285/75r16 tire is 32.83 inches (833.9 mm), while the 285/70r16 tire has a diameter of 31.71 inches (805.4 mm), resulting in a 1.12-inch (28.5 mm) difference in height between the two sizes.
Our Observations
When it comes to swapping your 285/75r16 tires for 285/70r16, the differences in on-road performance are relatively minor for most drivers.
The slightly smaller size may firm up the ride a bit and cause your speedometer to read a hair fast, but handling and gas mileage likely won’t see a huge impact.
For off-road applications though, that 6.7% shorter sidewall is worth weighing carefully. You give up some valuable ground clearance, impact absorption, and traction – all key factors when navigating rough terrain. It’s not an insurmountable difference, but it’s one that dedicated off-roaders need to consider.
At the end of the day, tire sizing is a balance of variables. The 285/70r16 is a reasonably close substitute for the 285/75r16 in many cases, but that 3.4% difference in overall diameter makes it a bit of a judgement call. Talk to your mechanic about your specific vehicle and driving habits to decide if it’s the right swap for you.
Meet Caitlin McCormack, a Tire Size Expert and Blogger Passionate About Everything Related to Tires. With Years of Experience in the Tire Industry, Caitlin Has Become an Expert in Tire Sizes and Their Impact on Vehicle Performance.