Tire Size 285/70r17 vs 315/70r17
Switching from 285/70R17 to 315/70R17 tires is not recommended due to the 5.1% difference in diameter, which exceeds the acceptable 3% range.
This change would significantly affect vehicle performance, safety, and handling. If you still want to make the switch, you’ll need to make adaptations to your vehicle to prevent issues like rubbing and clearance problems.
285/70r17 vs 315/70r17 Table
The Big Tire Switch
Thinking about upsizing your tires from 285/70R17 to 315/70R17? Hold on to your steering wheel, because we’re about to take a deep dive into the world of tire fitment!
This change might seem like a small jump in numbers, but it can have a big impact on your ride. Let’s break it down in simple terms. Imagine your tires are like shoes for your car.
Just like how wearing shoes that are too big can make you trip, putting oversized tires on your vehicle can cause all sorts of problems. But on the flip side, bigger tires can also give your ride some cool benefits, especially if you’re an off-road enthusiast.
The Numbers Game
The change might not sound like much, but in the tire world, it’s a pretty big deal. We’re talking about a tire that’s:
- 1.65 inches (42 mm) larger in diameter
- 1.18 inches (30 mm) wider
- 0.83 inches (21 mm) taller in sidewall height
That’s like going from a size 10 shoe to a size 11 and a half!
Main Difference
The most significant change is the 5.1% increase in overall diameter. This seemingly small percentage can lead to substantial alterations in vehicle performance, affecting everything from speedometer accuracy to gear ratios.
The wider tread and taller profile also mean more rubber meeting the road, potentially improving traction but also increasing rolling resistance.
On-Road Impact
On the pavement, you’ll notice some changes:
- Speedometer Shenanigans: Your speedometer will be off by about 5%. When it says you’re going 20 mph, you’re actually cruising at 21 mph. It might not sound like much, but it can add up over long distances.
- Fuel Economy Fumble: Bigger tires mean more rubber on the road, which can lead to increased rolling resistance. This might make your vehicle work a bit harder and gulp down more fuel.
- Handling Hiccups: The extra height can raise your vehicle’s center of gravity, potentially making it feel less stable during sharp turns or sudden maneuvers.
- Braking Battles: With more rotating mass, your brakes might need to work harder to slow you down. This could lead to longer stopping distances.
Off-Road Advantages
If you’re a mud-slinging, rock-crawling off-road warrior, the upsized tires might be just what you’re looking for:
- Ground Clearance Gain: The extra 0.83 inches of sidewall height translates to more ground clearance, helping you clear obstacles more easily.
- Traction Triumph: The wider tread (1.18 inches more) gives you a bigger footprint, potentially improving grip in loose or slippery conditions.
- Float Like a Butterfly: The larger diameter can help you “float” better over soft surfaces like sand or snow.
- Obstacle Overcome: Bigger tires can roll over larger obstacles more easily, making your off-road adventures a bit more adventurous.
Fitment Frustrations
Before you rush out to buy those beefy new tires, consider these potential pitfalls:
- Rubbing Ruckus: The extra size might cause your tires to rub against your fenders or suspension components, especially when turning or under load.
- Suspension Stress: Your suspension and steering components will be dealing with more weight and leverage, which could lead to faster wear and tear.
- Gearing Grief: The larger diameter effectively changes your gear ratios, which might result in slower acceleration and potentially strain your drivetrain.
- Calibration Conundrum: You may need to recalibrate your speedometer and other electronic systems to account for the size difference.
Our Observation
Switching from 285/70R17 to 315/70R17 tires offers a mix of benefits and challenges. Off-road enthusiasts will appreciate the increased ground clearance, better traction, and improved obstacle clearance.
However, these advantages come with on-road trade-offs, including potential fuel economy decrease, handling changes, and the need for vehicle modifications.
The 5.1% diameter increase, while beneficial off-road, exceeds the recommended 3% limit, affecting speedometer accuracy and gear ratios.
For daily drivers, the negatives may outweigh the positives, but for dedicated off-roaders, the benefits could be worth the necessary adaptations.
Careful consideration of your driving habits and willingness to make vehicle modifications is crucial before making this significant tire change.
Will my speedometer be affected by this tire change?
Yes, your speedometer will be off by about 5%. When it shows 20 mph, you’ll actually be going 21 mph.
How much will this tire change affect my fuel economy?
The larger tires may slightly decrease fuel economy due to increased rolling resistance and weight.
Do I need to modify my vehicle for these larger tires?
Most likely, yes. You may need to make adaptations to prevent rubbing and clearance issues.
Will this tire change affect my vehicle’s handling?
Yes, it can raise your vehicle’s center of gravity, potentially affecting stability during turns.
Are there any benefits to this tire change for off-road driving?
Yes, you’ll gain ground clearance, potentially better traction, and improved obstacle clearance.
Remember, when it comes to tire changes, it’s not just about looks. Consider your driving needs, vehicle capabilities, and be prepared for some potential modifications. When in doubt, consult with a professional to ensure you’re making the best choice for your ride!
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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.