Plus One Tyre Sizing: Learn How To Plus Size Tyres & Wheels (2023)

When it comes to performance tyres for your vehicle, sometimes big really is better.

JAX Tyres specialise in ensuring that the tyres we fit are not only the safest and most appropriate tyre options for your vehicle, but that they suit the needs of you and your specific on and off road activities, in accordance with local legislation.

But if your vehicle is a little more than just something you use to get from A to B, your thoughts may turn to choosing wider tyres, which fit larger diameter wheels that will meet your performance goals.

Enter the world of Plus Sizing.

Big is Beautiful

Plus Sizing your tyres, basically means installing tyres on to your vehicle that have a larger wheel diameter than the standard tyre fitment, while retaining the overall rolling radius the same, which is achieved by reducing the tyre profile.

Sound a bit complicated?

Stick with us and we'll break it all down for you.

A few years ago, tyre Plus Sizing was a realm it seemed only the most dedicated and performance-minded car buffs among us knew much about.

But at JAX Tyres, we can think of plenty of reasons why up Sizing could be a tyre option to suit many, and we pride ourselves on meeting your Plus Sizing needs professionally and safely.

The Thick and Thin of Plus Sizing

Plus Sizing your tyres can be also referred to as stepping up.

(Video) How To Make Sure Your Tyres Will Work With Your Wheels & Frame | GCN's Guide To Tyre Compatibility

So if your standard fitment was a 15 inch wheel, a Plus One tyre would be 16 inch and a Plus Two would be 17 inch etc.

The diagram below shows the permissibile conversion from a 15" through to a 20" tyre.Plus One Tyre Sizing: Learn How To Plus Size Tyres & Wheels (1)

While it may sound simple just to increase the diameter of your wheels, as you step up size notches, attention must be paid to the Aspect Ratio of the tyre too.

A tyre's aspect ratio is the percentage that refers to the relationship of the height of the tyre's sidewall to its width.

The lower the figure, the greater a tyre's section width. The importance here is to ensure that the wider tyre does not intefere with any of the vehicle's body parts. A wider tyre will provide you with increased grip and better braking performance but if it comes into contact with any mechanical part of the vehicle, this is dangerous and could compromise the safety of you and other road users.

Professional Plus Sizing is a Must

If the mathematics of tyre Plus Sizing is making your head spin, don't despair - JAX Tyres's qualified tyre professionals will handle these considerations for you.

All you have to do is to consider the diameter of the wheel you want to Plus Size and what results you're looking to achieve.

When it comes to working out how much to Plus Size your tyres and the performance outcomes you can expect, it pays to first consider what you're hoping to gain from your Plus Sizing experience.

The Pros of Plus Sizing

As we mentioned earlier, you don't have to be a performance driver to benefit from tyre Plus Sizing.

Put simply, Plus Sized tyres can improve the handling of your car!

(Video) Understanding Tire Sizes | Tech Tuesday #145

Each Plus Size level you move up will lessen the amount of tyre to rigid alloy - this means your tyre tread sits more squarely on the road and your car will respond better to your responses when braking or accelerating.

A professionally Plus Sized vehicle - as you would expect from a JAX Tyres Tyre dealer - will also ensure that speedometer and odometer accuracy is kept in the same, it might even be improved, and in most cases vehicles with Plus Sized tyres certainly look more visually appealing.

Considering the above, you can see that the two main reasons why people opt for Plus Sized tyres are:

  • Performance
  • Appearance

Plus Sized performance

When it comes to maximising the performance of your vehicle, it makes sense that your wheels will be one of the first considerations you make.

It doesn't take a automotive expert to understand that a wider tyre offers greater traction & grip on the road, but there is also the benefit of the shorter tyre sidewall it provides. For those not in the know, a tyre's sidewall is where numbers and letters, which make up the international identification system for tyres, are presented.

The sidewall numbers and letters will normally tell you the tyre's:

  • Brand - The company that manufactured the tyre
  • Series - The manufacturer will create a series of tyres that differ in terms of performance and handling characteristics
  • Model - This takes into account the tyre's construction, tread design and ride
  • Width - Important when Plus Sizing - this number will tell you the width of the tyre in millimetres.
  • Aspect Ratio - The height of the tyre sidewall from the rim to the tread - expressed as a percentage.
  • Speed Rating - The maximum speed the tyre is designed to travel at a given load
  • Load Rating - The maximum load the tyre is designed to carry at a desiginated maximum speed.

Customers who choose to Plus Size their tyres may have also heard about the benefits of getting the shortest sidewall height possible.

A shorter sidewall will produce crisper handling and better steering, but if the sidewall is too short the tyre can become overly "stiff" and can potentially make for a harsher ride for drivers and passengers.

For Example: A Plus One Plus Size would mean your wheel rim is half an inch closer to the ground than your Standard tyre size.

A Plus Two Plus Size would place your wheel rim 1 inch closer to the ground than your Standard tyre size.

(Video) Wheel and Tire Balancing, right and wrong way : Lucore Automotive

Plus Sized Appearance

Have you ever pulled up next to a car at the lights and remarked at how sporty or extreme it looked?

Pay more attention to its tyres next time - it's likely that the tyre fitments are plus sized!

While we don't suggest you think solely about appearance when deciding if Plus Sizing your tyres is an idea for your vehicle, there is no doubt that Plus Sized tyres can provide an edgier look for vehicles. This is usually because of the shorter sidewall, which means the rim is closer to the bitumen than normal.

Just remember - the team at JAX Tyres are tyre experts. Trust your local JAX Tyres to supply you with all of the knowhow, information and products that you will need to achieve the performance and appearance outcomes that you desire by fitting Plus Sized tyres to your vehicle.

Plus sized precautions

There are a few considerations you should make when Plus Sizing the tyres on your vehicle, and of course, always chat to a qualified team member at your local JAX Tyres about any concerns you may have.

Keep in mind:

  • A shorter tyre sidewall would mean the wheel rim is closer to the road - imagine what might happen if you hit a pothole at speed or find yourself battling road obstructions.
  • Passenger comfort may suffer slightly with a Plus Sized package. This is because the vehicle suspension has been set considering smaller diameter wheels and tyres having larger sidewall heights (greater aspect ratio). While this is no issue whatsoever for a performance vehicle, if your car's sole purpose is to drive the kids around, Plus Sizing may not be the best option in terms of family driving comfort.

Plus and Minus

Keep these quick tips in mind when making Plus Sizing plans for the tyres on your vehicle.

  • Your Plus Sized tyres should have the same rolling circumference as the Standard model recommended for the vehicle. Talk to your JAX Tyres tyre technician about what this means. Essentially this is to ensure that the vehicle's speedometer and electronics, such as traction control and anti skid devices, are not put out of calibration.
  • The Plus Sized tyre has to fit the wheel rim width; you must follow manufacturer guidelines here because anything other will not be safe.
  • You need to select Plus Sized tyres with an equal or higher load ratio. It is not legially permissibile to fit tyres that have a lower load carrying capacity that the original fitment.
  • Be cautious of inflation pressure, it must be in accordance with the vehicle manufacturer's prescribed levels that are clearly indicated on the tyre placard (located normally in the inside of the driver's door) or vehicle handbook. Ask your JAX Tyres technician about the importance of correct tyre pressures.
  • Be cautious of speed ratings; never choose a Plus Size tyre with a lesser speed rating than your standard tyre recommendation for the vehicle.
  • Ask your JAX Tyres technician about things you might need to think about if you ever need to add tyre chains to your Plus Sized tyres.
  • Remember that Plus Size tyres can impact your braking performance. A JAX Tyres technician fitting your Plus Sized tyres will run you through the ins and outs of this, but it is especially prevalent in SUV vehicles and has to do with the wider diameter of the tyre weighing more and making it tougher for your braking system to stop a heavier vehicle.

The Legislation

It is important to be aware that there is State Legislation regarding altering tyre and wheels from the original vehicle fitment.

The legislation for each of the states where JAX Tyres has a service outlet is summarised in the links below. This information could be subject to periodical change and is provided ONLY as an indication of local state regulations at this time.

For further details we suggest that you visit your local road transport authority or consult with your local JAX Tyres store manager, who will be pleased to assist with the technical requirements.

(Video) Measure for Custom Wheel & Tire Sizes - Summit Racing Quick Flicks

NSW Guidelines for Alternative Wheels and Tyres:

Click here for the RTA Guidelines for Alternative Wheels and Tyres.

QLD Transport Modifications Guide:

Click herefor the QLD Transport Modifications Guide.

VIC Light Vehicle Construction and Modification Guide:

Click here for the Light Vehicle Construction and Modification Guide.

TAS Vehicle and Traffic Regulations Guide:

Click here for the Vehicle and Traffic Regulations Guide.

ACT Guidelines for Alternative Wheels and Tyres:

We are currently in the process of clarifying the requirements.

In all cases, where tyre and wheel fitments are being changed from the original equipment, it is good practice to inform and involve your insurance company.

Plus Sizing Professionals

If you have decided that tyre Plus Sizing is the way forward for you, stop by your local JAX Tyres store and have a chat with any of the friendly staff on hand.

When discussing your Plus Sizing package with JAX Tyres Plus Sizing professionals, prepare to discuss:

  • Tyre Diameter - Ask the technician everything you need to know about the outside diameter of the Plus Sized tyre when it is mounted to the car and inflated as directed.
  • Overall Width - The width of the cross section of the tyre when mounted and inflated as directed.
  • Section Height - The space between the bead and the tread of the tyre.
  • Aspect Ratio - The tyres section height in relation to its section width - expressed as a percentage.
  • Tread Width - The distance between the inner tread shoulder and the outer tread shoulder.

Always ensure that whenever Plus Size tyres are fitted that you carefully check that there is no interference of the tyre against the vehicle body or wheel arch when the steering is on maximum lock.

Sometimes bigger really is better. Chat to your local JAX Tyres about Plus Sizing your tyres today!

(Video) Everything You Need to Know About Tires on Your Car, Truck or SUV


What is tire sizing plus 1? ›

PLUS ONE. If the wheel size is increased by one inch it is “Plus One.” This sizing mounts tires with an increased section width and a lower aspect ratio on wheels of a larger diameter. A Plus One fitment for a car with 16-inch original equipment wheels would use 17-inch wheels.

What is plus 1 and plus 2 wheels? ›

"Plus one" means that you increase the wheel diameter by one inch more than the original equipment (OE) wheel. "Plus two" means increasing the wheel diameter by two inches, and likewise with "plus three" increasing three inches, and so on.

How do I learn tire sizes? ›

The two-digit number after the slash mark in a tire size is the aspect ratio. For example, in a size P215/65 R15 tire, the 65 means that the height is equal to 65% of the tire's width. The bigger the aspect ratio, the bigger the tire's sidewall will be.

How do I know what size tire will fit my rims? ›

Identifying Compatible Tire Sizes

The first is in the driver's door jam. Open up the driver's door and look within the door jam or on the door itself and locate the sticker that has your tire information on it. Here you will find the wheel (rim) and tire size your vehicle came equipped with from the factory.

Are tires one size fits all? ›

Tires are a part of the wheel setup. For instance, your vehicle has a set size of rims, but you can buy different sizes of tires to fit those rims, as long as the middle of the tires is the correct size. That being said, a vehicle with bigger rims will often be able to fit larger tires than other vehicles.

Can I go one size wider on my tires? ›

As a general rule of thumb, it's safe to fit a tire up to 20 millimeters wider than stock on the original rim. The actual width of the tire will vary depending on the width of the rim: The tire will expand 5 millimeters for every half-inch (12.5 millimeters) increase in rim width.

What width rims for plus size tires? ›

Wider tires—2.8 inches and up—are considered “plus” tires, as their casings are even larger and are designed for rim widths between 35mm and 40mm.

What does 20 inch plus wheels mean? ›

"Plus two" would add two inches to the tire width and wheel diameter, and so on. If you're looking at going from 18-inch wheels to 20-inch, you'd be looking at "plus two" sizing.

What is the 3% rule on tires? ›

As a general rule, you want replacement tires that are within 3 percent of the diameter (height) measurement of your existing tires' diameter — assuming your current tires are what your owner's manual recommends.

What are the three common tire sizing methods? ›

Three sizing systems are employed today for passenger tires: P-metric, European metric and alpha-numeric. The most common system is P-metric. The size designation indicates cross section in millimeters, aspect ratio, type of construction and appropriate rim diameter.

What does 265 70 r17 mean? ›

265 is the width, 70 is the aspect ratio, R stands for radial, 17 is the wheel diameter and 115T is the load index and speed symbol. Cookie Settings.

Will any 20 inch tire fit a 20 inch rim? ›

Width Matters Too

Just because your rim is 20 inches in diameter and you found 20 inch tires doesn't mean they'll fit. You need to know the width of your rims before you can buy a set of tires.

What size tires can fit on a 17 inch rim? ›

Tire Sizes by Wheel Diameter
17" Options
20 more rows

What size tires can you put on a 16 inch rim? ›

Tire Sizes by Wheel Diameter
16" Options
14 more rows

Can I put different size tires on the front and back? ›

For optimal safety and performance, Continental recommends fitting the same tires to every wheel position on your car, so drivers should have the same brand, size, tread pattern, load index, and speed rating on the front and rear tires.

Can you run two different size tires on the same axle? ›

Having two different-sized tires on the same axle is generally not a good thing. If the diameter of the two tires is close, then the rolling radius is about the same, so in the short term, you probably won't have any damage, but long term, you run the risk of messing up your car's differential.

Do all 4 tires need to be same width? ›

It should go without saying, but all wheel drive and four wheel drives vehicles should have the same tire size on all four wheels. Having different sizes on some four wheel and all wheel drive vehicles can actually do damage to the vehicle.

Do thicker tires ride better? ›

As a general rule, bigger wheels result in a rougher ride. Switching to a smaller wheel and a thicker tire can give you a smoother ride without any major modifications to your car. However, if you go too crazy and change your wheel size too much, it can cause some problems.

Do you need an alignment after changing tire size? ›

When the tire size is different from the factory, a car's alignment will need to be adjusted after a tire change. This is because tires that are wider or taller than original equipment tires stretch the suspension slightly and cause changes in camber and caster angles, as well as toe angles.

What happens if your tires are too wide? ›

If disregarding the vehicle or tire manufacturer guidelines, there are potential hazards to fitting your wheels with wide tires. For one thing, tires may be more susceptible to aquaplaning or hydroplaning. Also, the car will have less control on slippery, loose surfaces like gravel.

What size tire will fit on a 9.5 inch wide rim? ›

Equivalency table
Rim widthMinimum tire widthIdeal tire width
8,5 Inches225 mm235 or 245 mm
9,0 Inches235 mm245 or 255 mm
9,5 Inches245 mm255 or 265 mm
10,0 Inches255 mm265 or 275 mm
12 more rows

Do I need wider rims for wider tires? ›

While you still need to ensure that wider tires will fit inside your wheel wells without rubbing, it's common to add an inch of width to your wheels—for example, going from a 7-inch-wide rim to an 8-inch-wide one. That allows a wider tire to be mounted.

Do wider wheels make tires wider? ›

Putting the same tire on a wider rim means the tire keeps the same diameter but gets a bigger width.

What size tires can you put on a 20 inch rim? ›

Tire Sizes by Wheel Diameter
20" Options
19 more rows

What tire size gives the smoothest ride? ›

Smaller wheel = smoothest ride quality, low stability, predictable handling, average road noise. Medium wheel = average ride quality, average stability, predictable handling, low road noise.

What is the magic formula for tires? ›

The Magic Formula (Pacejka) tire model for the longitudinal force is described by the following mathematical expression:Fy=D·sin[C·arctan{B·κ−E·(B·κ−arctan(Bκ)}]for pure longitudinal (brake/drive) slip κ.

Should you always buy 4 tires at a time? ›

It's always best to replace all 4 tires at the same time. This is because all 4 tires spin independently of one another, and different tread depths and/or styles can cause them to spin at different speeds. That could potentially damage the drive train, and possibly affect an indirect TPMS system if the vehicle has one.

What size tire is best for winter driving? ›

A narrower tire does a better job in snow. As a rule of thumb, for winter tires you can reduce the width 10mm, increase the aspect ratio 10 percentage points, and get a wheel one inch smaller — in this case 215/60R16. This is called Minus One sizing.

What does the R mean in tire size? ›

Radial tires are the most common tires on the road in the United States today; thus “R” will usually be shown in the tire size designation. Radial construction means the tire's internal ply cords are oriented in a radial direction, from one bead over to the other, essentially perpendicular to the direction of rotation.

What is the most popular tire sizing system used today? ›

Metric & P-Metric Sizes

Most passenger car tires today are “metric” or “P-metric” (similar, with the “P” designating passenger car use).

What is the most important number on tire size? ›

The very last number in the sequence, “15,” is the diameter of the tire. This is an important number—this is the number you'll refer to when you need to know your tire size! The “15” indicates that this particular tire would fit a rim with a 15-inch diameter.

Should better tires go on front or back? ›

According to Tire Review, new tires should always go in the back. Rear tires provide the vehicle stability, and if they have little tread, then stability is lost.

What does M&S mean on a tire? ›

What Does M+S Mean on a Tire? M+S is an acronym for “mud and snow.” It's a branding found on the sidewall of some all-season tires. It's important to note there is no actual testing or accreditation to earn the M+S label.

What does 111s mean on a tire? ›

The measurement ends with the load index 111 or maximum weight that each wheel can bear and the speed index S or the maximum speed for which the tire has been approved.

Which tire is taller 70 or 75? ›

The higher the number, the taller the sidewall (and vice versa). From the foregoing, it appears that tires with the same section width should have the same width regardless of aspect ratio.

What does the V or H mean on tire size? ›

The speed rating on a tire indicates the fastest speed a tire can handle before it affects the tire's performance. Lower speed ratings (such as A8 or B) will mean that you won't have good control or handling of the car at highway speeds. Higher speed ratings, like H or ZR, can handle far beyond a normal highway speed.

What does V and H stand for on tire size? ›

The speed rating is expressed with letters, and there are several. Common examples are H and V: An H-rated tire can safely run at a sustained maximum speed of 130 mph and a V-rated tire at 149 mph. Other common speed ratings are S (112 mph) and T (118 mph).

What are the disadvantages of 20 inch rims? ›

Con: Greater Risk of Damage

Compared with the rubber surrounding a 17- or 18-inch wheel, the tire on a 20-incher doesn't have nearly as much sidewall, which not only makes it stiffer, but increases the likelihood that an obstacle on the road will cause a puncture or damage the wheel.

Can I put 18 inch tires on 19 inch rims? ›

Despite what your car salesperson may have told you, it's OK to get an 18-inch spare to go with your 19-inch wheels.

What is the most common 20 inch tire size? ›

The most popular 20" tires
  • P255/55R20.
  • 265/50R20.
  • 275/55R20.
  • 275/60R20.

Can I put any 17-inch tire on a 17-inch rim? ›

For diameter you'll need to be sure that your tires and wheels are an exact match, e.g. a 215/65R17 tire will only fit on a 17" diameter wheel. There's a bit more flexibility when it comes to wheel widths.

What's the difference between a 16 inch rim and a 17-inch rim? ›

The difference is of tyre size, where 16-inch wheels come with tyres that have larger sidewalls that act as cushions against sharp edges on the roads, like ruts and potholes. While 17-inch tyres look much better, provides a better grip on the road and no doubt increases the car ground clearance too.

What is the most common 17-inch tire size? ›

The most popular 17" tires
  • 215/55R17.
  • 225/45R17.
  • 225/65R17.
  • 265/70R17.

Can I put any 16 inch tire on a 16 inch rim? ›

Just considering rim diameter and tire bead diameter only, the answer is yes you can, if the tire is up to 1″ smaller, but don't do it. I have seen 16″ tires on 16.5″ rims. That mistake is not uncommon. I have seen 13″ tires on 14″ rims, and 14″ tires on 15″ rims.

Will any 16in tire fit on a 16 inch rim? ›

Wheel Diameter

In our example, the diameter is 16 inches. Wheel diameters can vary, but they typically range from 13"-24" (or higher for specialized low profile fitments). Only wheels and tires of the same diameter can be safely mounted together, meaning you can only mount a 16" tire on a 16" wheel.

Are 16 inch wheels better than 17 inch? ›

AAA - Yes, wheel size has a big impact on ride comfort. The smaller 16-inch wheels come with tyres that have larger sidewalls that act as cushions against sharp edges on the roads, like ruts and potholes. While 17-inch tyres look much better, the shorter sidewalls aren't as good in filtering out road shocks.

Is a plus a good tire? ›

They offer excellent performance, good ride quality and a safe driving experience with all of their models. All of the brands are manufactured in modern factories.

What is plus minus tire sizing? ›

A lot of drivers have already heard about Plus sizing, but most drivers do not know what the minus sizing is. The Minus sizing is a practice of mounting taller profile tires on smaller diameter wheels. This is the reverse concept of plus sizing and accordingly, it is called the minus concept or the minus sizing.

What do numbers mean on tire size? ›

The number 215 indicates the tire width in millimeters from sidewall to sidewall, so 215 millimeters in this case. 65 is the aspect ratio code, which means the ratio of its height to width. This tire has a height equal to 65% of its width. R indicates radial construction. 15 is the wheel size.

What is the strongest brand for the tires? ›

Michelin has once again topped the tyre table within Brand Finance's ranking of the world's strongest and most valuable brands. Michelin achieved a brand value of US$7.7 billion and a brand strength index score of 85.8 out of 100.

Is Firestone better than Tires Plus? ›

Firestone Complete Auto Care is most highly rated for Compensation and benefits and Tires Plus is most highly rated for Culture.
Overall Rating.
Overall Rating3.23.3
Job security and advancement3.02.9
2 more rows

Is a wider tire better or worse? ›

Narrow tires are cheaper but wider ones look better

The tire width will affect their price and several other characteristics, such as grip, noise level, driving comfort, and appearance. Replacing narrow tires with wider ones will usually increase rolling resistance and, therefore, slightly increase fuel consumption.

Can you use 2 different tire sizes? ›

Having two different-sized tires on the same axle is generally not a good thing. If the diameter of the two tires is close, then the rolling radius is about the same, so in the short term, you probably won't have any damage, but long term, you run the risk of messing up your car's differential.

What is the most important number on a tire? ›

A tire's load index is a measurement of how much weight each tire is designed to support. The larger the number, the higher the load capacity. This is one of the most important numbers on your tire.

What does R mean on a tire? ›

“R” stands for the construction method of the tire indicating the tire is a radial tire. The following two numbers (16) indicate the diameter of the wheel rim in inches. The next two or three numbers (94) indicate the load index of the tire.


1. Hed Talks: Choosing Tire Width for Plus Rims
(HED Cycling)
2. Tires & Wheel/Rim sizing explained | Ere Research Tech Talk
(Ere Research)
3. Understanding how to pick out the right size Tires, Rims and wheels
(Stanley "Dirt Monkey" Genadek)
4. Must Watch Before Buying Wheels - Getting The Wheel Size Right
(Ratchets And Wrenches)
5. How To Measure Wheel Size and Fitment Diameter Offset Backspacing Width Bolt Pattern Lug Nuts
(JEGS Performance)
6. How to measure your Wheel Offset / ET accurately


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