Plus Sizing refers to tires that are wider and have a shorter sidewall. The result is a larger contact patch and a more sporty look.
Drivers choose Plus Sizing to improve:
• Steering response
• Handling
• Cornering ability
• The look of your vehicle (posture).
What's "Inch Up"?
"Inch Up" is the process of mounting a lower aspect ratio tire and
larger diameter wheel on your car. This creates a larger contact patch
and a shorter sidewall.
Why "Inch Up"?
"Inch Up" to improve your vehicle's performance and appearance.
• Increased Steering Response
• Improved Dry Handling
• Enhanced Cornering Ability
• Aggressive Good Looks
How Can You "Inch Up"?
"Inch Up" with the experts in plus sizing, by increasing RIM &
TIRE size, or just Tire.
Rims ->[Check 'Em Out]
• Innovative Technology
• Precision Fit
• Wide Size Selection
• Proven Performance
"Inch Up" may be done in several ways. The most popular are:
1. Plus Zero
This method utilizes the same wheel diameter as Original Equipment(OE),
but incorporates a tire with a larger than OE section width and smaller
than OE aspect ratio. For example, replacing an OE 175/70R14 tire (on a
5.5-inch wheel) with a 195/60R14 tire would be a proper Plus Zero fitment.
Note that this may require a replacement wheel to maintain proper rim width
for the new tire.
2. Plus One
This method utilizes a one-inch larger diameter wheel, in conjunction
with a tire of a one-step lower aspect ratio. An example of an appropriate
Plus One fitment is to replace an OE 175/70R13 tire (23-inch overall diameter)
with a 185/60R14 tire (22.9-inch overall diameter). Note that this method
always requires a replacement wheel.
3. Plus Two
This method utilizes a two-inch larger diameter wheel, in conjunction
with a tire of a two-step lower aspect ratio. An example of an appropriate
Plus Two fitment is to replace an OE 175/70R13 tire (23-inch overall diameter)
with a 195/50R15 tire (22.8-inch overall diameter).
An example of upsizing the rim, while keeping the overall diameter
of the wheel the same
Basically, each time you add 1 inch to the wheel diameter, add 20mm to the tire width and subtract 10% from the aspect ratio. This compensates nicely for the increases in rim width that generally accompany increases in diameter too. By using a larger diameter wheel with a lower profile tire it's possible to properly maintain the overall rolling radius, keeping odometer and speedometer changes negligible. By using a tire with a shorter sidewall, you gain quickness in steering response and better lateral stability. The visual appeal is obvious, most wheels look better than the sidewall of the tire, so the more wheel and less sidewall there is, the better it looks. However, be prepared for a stiffer ride as there will be less sidewall to cushion undulations in the road. I have found a 17" tire (Tech 4000) with 400 tread (more cushion), and the ride has improved over OE tires, keeping the same performance. You should notice, as your tread wears, your ride gets stiffer.
An independent research company recently conducted a test to determine the effect "Inch Up" has on handling. Included here is an abbreviated summary of the test results.
The vehicle used for this comparison was a 1989 Mazda RX-7 SE. The original equipment tire is a 185/70HR14, and is mounted on a 5.5-inch wide wheel. The test was conducted on a dry asphalt surface. As the results from the lateral acceleration and handling course indicate, each successive plus size led to a noticeable increase in handling performance.
Warning:
When changing to a non-OE tire size, always consult the load/inflation
charts to determine proper inflation pressure to maintain OE load-carrying
capacity. Talk to your local Kal Tire store about your Plus Sizing options.
USE THE INFORMATION BELOW FOR RFERENCE
Example: 225/40VR17. The units are both metric and imperial. The 17
is the inner diameter of the tire in inches. The 225, is the width of the
tire in millimetres. In this case the widest part is 225mm, which
is 8.8" wide (25.4mm = 1 inch, so 225mm divide by 25.4mm = 8.8").
The 40 represents the percentage of the profile, also known as the aspect
ratio. In other words, the smaller the number, the more the tire looks
like a rubber band on the wheel. As its 40% of the height of the tire,
then the profile in mm is 0.40 x 225mm = 90mm. If there isn't a aspect
ratio shown on the tire then it has a default ratio of 82% (looks like
tractor tires).
The diagram below shows the aspect ratios for same size rim, large to
smaller tirel. AS you can see, the rim is the same size, but the
overall diameter of the wheel is changed with the lower aspect ratio.
TRUCK
SEDAN
SPORT/COUPE
