One of the easiest and most effective ways of modifying your truck is to change the road tires to more rugged and capable all-terrain tires. Off-road tires are not only about looks but serve a valuable role in making your truck more capable in adverse conditions. If you want to install off-road tires, do you have to buy new wheels?
Within reason, it is possible to install Off-Road tires on Stock rims. The off-road tire diameter- which is the inside measurement of the tire – must be the same size as the rim. A tire’s width can be ¾ inch wider, and a bigger sidewall height can also fit a stock rim.
If a truck is going to be used for an activity that involves traveling off paved roads, then considering a tire with an off-road focus is very wise. Can off-road tires fit the vehicle’s existing rims, or does the fitment of off-road tires necessitate new wheels?
You Can Install Off-Road Tires On Stock Rims
There are many misconceptions about what type of tires should be fitted to off-road vehicles.
Before considering whether you can put off-road tires on Stock rims, let’s understand how tire measurements work.
Printed on the side of a tire, you will see a series of numbers and letters. These identify the tire and are a standardized method used by all tire manufacturers.
An example of this number is P215/65R15. The following deciphers the code:
- The “P” indicates that the tire is designed for a passenger vehicle. If an “LT” replaces the “P,” this means the tire is intended for a light truck or an off-road vehicle.
- The “215” refers to the tire’s width; this is always measured in millimeters.
- The “65″ refers to the tire’s sidewall height; this is always measured as a percentage of the tire’s width. In this example the sidewall height is 215 * 65% = 162.5 millimetres.
- The “R” refers to the tire’s construction – “R” means a radial tire, and if no letter is printed, it is constructed as a cross-ply tire.
- The “15” refers to the size wheel the tire will fit. Ironically this measurement is expressed in inches (not millimeters like the width and sidewall height). In our example, the tire will fit a 15-inch wheel.
If the off-road tire you consider fitting to your vehicle has the same size (last number in the sequence) diameter as your existing rims, you can install it on your vehicle.
Can You Fit Any Width Or Height Tire?
Can you fit any width or height-sized tires to your vehicle if a tire is the same size as the wheel?
Installers work on the rule that you should not increase the tire’s width by more than 20 millimeters (3/4 inch).
The example used before, where the stock tires are 215 millimeters wide, would mean that the width of the new tire should be no greater than 235 millimeters.
The only restriction regarding the sidewall height will be the vehicle’s capability. Installing a tire with too high sidewalls may result in the tire rubbing in the wheel well or the fender.
Trucks and specialized off-road vehicles wheels tend to have bigger wheels. These are more suitable for increasing the sidewall height of the tires.
Why Would You Want to Change The Tire Size?
Sometimes, upgrading to bigger off-road tires is purely for cosmetic appearances giving the owner a self-perceived amount of street cred.
The real reason should be a serious and considered attempt to increase the vehicle’s off-road prowess. To make an informed decision on what tires to install, you need to consider the following factors:
- The type of terrain you will drive on.
- Whether you are installing a lift system for the suspension.
- If you intend to travel on rough off-road terrains, a larger sidewall height may be more suitable.
- The finish of the wheel.
- The fully-loaded vehicle’s weight.
These factors are explained in more detail.
Would Off-Road Tires On Stock Rims Help In Rough Terrain
Off-road tires will be more suitable if you plan to drive off paved roads. You will need to decide whether you want your tires to have general all-terrain capabilities or whether they will need to be focussed on a specialized activity, such as traveling through mud or slippery surfaces. They could be specialized rock-climbing tires with more rigid and higher sidewalls.
Would Installing A Lift System Affect Stock Rims?
If you are installing a lift system, you will need to consider the backspacing and offset of the tire.
Offset refers to how the tire is mounted and fits in the wheel wells.
- A zero offset is when the hub mounting surface is in line with the wheel’s centerline.
- It is called a positive offset when the wheel is moved outside of the wheel well and more to the street side. Wider wheels with a positive offset may stick out from the side of the wheel well.
- A negative offset is when the wheel is closer to the car’s body. Manufacturers tend to use a negative offset to allow for wider tires that will still fall in line with the vehicle’s body.
Backspacing is the measurement used on the inside of the wheel’s mounting surface to the back edge of the wheel. A backspace of 6 inches would mean that the wheel has a positive offset.
These measurements are vital as if they are incorrect, damage to the vehicle will result.
For Rough Terrain, Consider Taller Tire Sidewalls
Increasing the tire’s height has profound positive and negative effects on the vehicle.
- Taller tires will result in lower revs, which will equate to better fuel economy
- An improved ability to clear obstacles. If you need to reduce the pressure in the tires to traverse a particular obstacle, the higher the sidewall, you will lose less ground clearance.
- Your vehicle will have less power. Increasing the tire size has the same effect as changing to a higher gear. You can reduce this effect by having a specialist firm swap to a lower gear in the differential.
The Finish Of The Wheel On Stock Rims
Many wheel finishes are available. If you use the vehicle for regular off-road work, you will find that a matt finished wheel will be easier to maintain.
The Weight Rating Of The Wheel On Stock Rims
Modern off-road capable vehicles are designed to handle ever-increasing loads. You need to ensure that the tire you select is rated to match the vehicle’s capability.
Conclusion
The off-road tire should not be 20 millimeters wider than the stock tire fitted by the manufacturer. As long as the tire is designed to fit your wheel size, you can install any suitable off-road tire onto your Stock rims.