Ever wondered what low-profile tyres are? Well wonder no longer, as we explain tyre profiles and what they mean for your car. If you've been looking at used cars for sale, or you want to buy new tyres for your car, then you might have come across the phrase 'low profile tyre'. But what does it mean? Well, obviously it relates to your car's tyres, and it refers to the size of the tyre sidewalls in relation to the tread that comes into contact with the road.
If a tyre has a low profile, it means that the sidewall of the tyre is shallower than normal, and it usually means that the tyre is fitted to a larger diameter wheel. Low-profile tyres with big wheels are usually the preserve of higher performance models in a new carrange, although there's nothing stopping owners from fitting bigger wheels with low-profile tyres to a standard model.
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But why would you want to add low-profile tyres to your car? Well, it's a cost-effective way of giving an ordinary model a sharper look. A set of shiny, larger diameter alloys fitted with low-profile tyres can perk up the appearance of any car, especially if it originally came with steel wheels and cheap plastic trims. Another benefit of low-profile tyres is an improvement in a car's handling.
Of course the opposite of a low profile tyre is a high profile one, and the difference is visually obvious when the two are compared, because there's a lot more tyre sidewall before you get to the wheel. You'll normally find these on basic cars and 4x4s that need the extra height to protect the wheels from damage on rough terrain. You'll also find higher tyre profiles on Formula One cars, as the tyre and wheel dimensions are fixed by the rules.
The size of a tyre sidewall is recorded on the sidewall itself, as part of the string of numbers that signifies the overall size of the tyre. This code shows the width of the tyre tread, the height of the sidewall and the diameter of wheel the tyre is designed to be fitted to. While the tyre width is in millimetres and the wheel size is in inches, the sidewall size is expressed as a percentage of the tyre's width. These percentages are set at five per cent increments, so the lower the number (down to about 30 per cent for the lowest of profiles), the shorter the sidewalls.
Low profile tyre pros and cons
One benefit of low-profile tyres is the fact they usually look smarter than standard tyre set-ups. That's because if you're going to fit low-profile tyres, you must put them on larger wheels so that the overall rolling diameter of your car's tyres and wheels stays the same.
This is important, because if you just go ahead and fit lower profile tyres to your existing wheels, the smaller rolling diameter will play havoc with your car's systems.
A smaller overall diameter of wheel and tyre will rotate faster than a standard one, so your car's odometer will click over faster, and show a higher mileage than you have actually travelled. It will also affect the reading of your car's speedometer, as you are likely to be travelling at a different speed to the one being shown. It will probably be a lower speed, but it's still inaccurate.
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Your car's gearing will also be affected, while modern safety electronics rely on a car's tyre diameter to function correctly in the event of an incident. Your car will also likely sit a little lower, so if it already has trouble scraping over speed bumps, this will only be made worse.
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As well as adding a sportier look to a car, low-profile tyres can boost a car's handling. The shorter sidewalls aren't as flexible as the taller ones on high profile tyres, which means the car doesn't roll and bounce about quite as much. This boosts grip and the effectiveness of the suspension at keeping the car stable in corners.
This can have beneficial effects for a car's performance, as extra grip means a car can go around a corner faster, but the downside to this will be a firmer ride over bumps. The tyre sidewall acts as part of the car's suspension, and if there is less sidewall and a smaller cushion of air to absorb bumps, these shocks will transmit through the wheels and suspension to the cabin, making for a more uncomfortable ride for passengers. In recent years, some car makers have designed their cars to be more comfortable on large diameter wheels as standard, although that is unlikely to be the case when fitting aftermarket wheels and tyres to a vehicle.
The question is whether you can put up with this extra firmness for the added grip and roadholding the tyres will provide. If you're increasing tyre size by an inch, it might not have a big effect on soaking up bumps, but if you're increasing size by two or three inches, then you're likely to notice the difference. And if the bumps are severe - especially crashing into potholes - then there's a greater risk of either the tyre or wheel suffering damage as a result, as a low-profile tyre doesn't have as much ability to absorb the impact as a standard tyre.
You’ll need to be more careful when parking too because low profile tyres put your alloy wheels close to the road and its various low level obstacles. Small kerbs and ridges that normal tyres would happily bump over can come into contact with your alloys and cause ‘kerbing’ damage when you have less protective rubber as a safety net.
Another negative of low-profile tyres is their higher cost. While the lower profile means there's less rubber to start with, these tyres tend to be designed with performance in mind, so they usually have more advanced construction so that they perform at their best. Of course, low-profile tyres need larger diameter wheels, and simply buying a set of these to fit them on will add to the expense.
Fitting low profile tyres: summary
For
- Improved looks
- Better handling
- More grip for extra performance
Against
- Reduced ride quality
- Increased cost
- Less protection for wheels and suspension
What are low profile tyres?
Today, there are many different tyre types available, including a broad range of low profile tyres for sale. Many drivers, however, are still not familiar with these options and are often unaware of a low profile tyres disadvantages and advantages.
Defining Low Profile Tyres
All car tyres are defined by various key parameters, such as their width, profile height and rim diameter. When it comes to working out the tyre size, all of these parameters are interconnected. As such, if one changes, the others must also be adapted.
This is because tyres need to maintain the total wheel diameter and height recommended by the car’s manufacturer. An important part of this is the profile height, also known as the tyre series, which is the ratio between the height section of a tyre (the sidewall) and the width. As such, the sidewall is never actively stated in a physical measurement, it is always a percentage in relation to the width.
If in doubt, remember that the Profile (Series) = Tyre Height / Tyre Width *100%
Of course, this dimension is not an absolute value but, rather, a combination of the width and height. This is important to note, because a small change in width will then change how ‘tall’ a sidewall is, even if the ratio is the same. The sidewall on a 205/55 R16 tyre, for instance, will have a shorter profile than a 225/55 R16option, even though both have a 55% ratio. Ultimately, the total diameter on the former option will be smaller.
So, with all this in mind, what are low profile tyres? To consider tyres low profile, they must have a relatively low profile. Many drivers would argue this is anything from 50 below, yet others would also count 55. Examples like the above can be considered low profile, as a result.
This is also something that has changed with time. In the 70s, anything with a ratio of 80 or less was considered a low profile option.
Who uses a low profile tyre?
Generally, low profile tyres are commonly found on medium and high-class vehicles, where they come factory fitted as original equipment. This is to make use of the many low profile tyre pros, which enhance racing characteristics and performance.
Because of this, as well as other advantages discussed shortly, such tyres are also used as replacement tyres for high class cars, or just by tuning enthusiasts looking to optimise their car.
What are the key characteristics of a low profile tyre?
The tyre industry, just like the wider automotive market, is constantly evolving. There is a very high rate of change, with a constant stream of new solutions and innovative trends. As such, the concept and characteristics of low profile tyres has also changed over time.
Recently, the 205/55 R16 has quickly established itself a firm favourite and is readily becoming one of the most popular tyre sizes for mid-range cars in Europe. Yet, because they are often used in such cars without rim protection, many people no longer consider them as low profile options.
As mentioned earlier, part of this is because two different tyres can have the same ratio, but it is the overall height of the sidewall that changes. As such, a 185/55 R16 tyre will be classed as low profile much more than a 205/55 R16, as the latter has a noticeably higher sidewall.
To surmise, we can generally assume that a tyre with a profile lesser than, or equal to, 50 or 55 can be considered as low, depending on the width of the tyre. Low profile options are also usually equipped with a rim protection flange, which is a sign many drivers use to determine if a tyre is low in profile or not.
What is the lowest profile tyre available?
In 2009, the ETRTO (European Tyre and Rim Technical Organisation) standards defined 20 as the lowest allowable series for tyre sizing. This meant that, for a number of years, tyres such as 375/20 R21 had the lowest profiles available.
However, manufacturers have started to push this boundary. Both the Nexen and Kumho tyre companies have introduced models with 15 per cent profiles. For Nexen tyres, this is the N3000 model, with a size of 365/15 R24. For Kumho, they have released the Kumho Ecsta SPT KU31, in a 385/15 R22 size.
Do low profile tyres wear more quickly?
When it comes to tyre construction, every model has to be designed for usability, as well as the durability set out by both its load index and speed index for its size. This is usually achieved by reinforcing the beading and the tyre tread. Since these two factors aren’t diminished by a smaller profile, it can be correctly assumed that low profile tyres last just as long as regular tyres.
However, the lower profile does make them more susceptible to damage. This includes driving without the correct tyre pressure, or with excessive loads. Similarly, driving over curbs or other obstacles, such as potholes, can cause extra damage.
Another factor you should consider is your driving style and character of the car you may wish to fit these tyres to. Low profile tyres are often used as sporting products, typically offering increased grip at the expense of quicker wear. As such, you may want to consider your practical requirements before choosing this option.
Currently, more and more models are also using run flat tyre technology. This allows for a decent level of driving, even when all tyre pressure is lost. These run flat options do, however, require additional reinforcement along the sidewalls and shoulders - similar to reinforced tyres - to allow the tyre to keep rolling.
How do low profile tyres influence suspension
If your car was originally equipped with low profile tyres by the manufacturer, you can be assumed that the suspension system is designed to provide the proper amount of functionality and durability.
Problems may, however, appear when the steering system and suspension and not adapted to larger rims and tyres that are less effective at cushioning. In these cases, the use of low profile tyres may lead to suspension failure more quickly. These tyres can also increase the risk of damaging your aluminium wheel rims, which are commonly used in this fashion. The rim protection will not save the rim if, for example, you drive over a hole in the road.
What pressure should you use in low profile tyres?
When it comes to low profile tyres, the right tyre pressure is vital. Over-inflation can significantly decrease the driving comfort, while an under-inflated tyre can lead to overheating and irreversible tyre damage.
Because of this, the recommended pressure values should be observed at all times. Some manufacturers will even give an approved tyre option for both high and low variants, well often recommend a higher pressure for the latter. This is usually only be around 0.2 bar, but it is important that you stick to the recommended value.
Many owners choose low profile tyres, but they need to consider the correct tyre pressure. Why is this important? When dealing with low profiles, a smaller volume of air has to carry the same load. The extra pressure helps to counteract this deficiency.
Low Profile Tyres: Advantages And Disadvantages
How many times have you noticed a car running with those cool wheels and tyres that look larger than the standard ones fitted on your car? Chances are quite a few times, so we thought we'd shed some light on your rubber doubts. What you're seeing on these cars is an aftermarket modification, that of the fitment of bigger rims and low profile tyres. These tyres are ‘thinner' than conventional tyres and thus allow for bigger wheels to be installed in the same wheel well. However, while these tyres certainly look the part, there is more to know about them before rushing out and purchasing a set for your car.
1. How to read your tyre size Every tyre has details of the size of the tyre along with other information. Watch this space for more about the information seen on tyres. For now, let's focus on the size. In the example alongside, the tyre size details are 305/30ZR19 and can be read as follows:
- 305: The width of the tyre in millimetres
- 30: The profile or aspect ratio of the tyre (read further for more)
- Z: The speed rating of the tyre (here rated ‘Z' for above 300 km/h)
- R: Radial construction
- 19: The diameter of the tyre in inches
2. What is a tyre’s profile? The profile of a tyre is the depth of the sidewall, or the height of the side of the tyre, which is expressed as a percentage of the tyre's width. In our example (the 305/30ZR19 tyre), the profile or aspect ratio of the tyre is an extremely low 30, which means the tyre's sidewall depth is 30 percent of the 305-millimetre width. Aspect ratios of low profile tyres usually begin from 60, moving downwards as the sidewall gets narrower.
3. Advantages of low profile tyres Apart from doing wonders for the looks of your car, low profile tyres offer greatly improved levels of handling and grip, especially in the dry. Your car will also brake much better, with a wider contact patch (the area of the tyre in contact with the road) that provides greater traction than a conventional tyre. Low profile tyres will benefit your car's cornering characteristics by being able to handle greater cornering forces (CF), and steering performance sees a marked improvement as well.
4. Disadvantages of low profile tyres Possibly the biggest disadvantage of low profile tyres in an Indian context is the high susceptibility to tyre and rim damage, since these tyres have a smaller air cushion to work with to absorb harsh impacts from our pothole-ridden roads. Road noise also increases with these tyres because of the larger contact patch, and the ride of your car can become much stiffer. One also has to be much more watchful in the rain, since cars shod with low profile tyres offer less resistance to aquaplaning (when the water on the road forms a layer between the tyre and the surface of the road, leading to the car losing traction and skidding). Fuel economy also takes a hit, and last but not least, these tyres are expensive, costing much more than standard tyres.
5. Important to know! Key to remember is car makers allow for a maximum increase of three percent of the original tyre size. Any further upsizing and it will actually take away from the aforementioned handling advantages because the wheel well will not be able to accommodate the oversize tyre. One can often notice tell-tale signs of damage like chipped rubber on these upsized tyres since they end up scraping the sides of the wheel wells.
Should You Put Low-Profile tyres on Your New Car?
Nearly every new car seems to offer low-profile tyres. I like the look, but I've heard folks complain about jarring rides, frequent blowouts, rim damage, and greater wear at lower mileage. Should I avoid them?
Low-profile tyres do seem to be popping up on a lot more cars these days, but they're being offered for several reasons. Bigger wheels and skinnier sidewalls in a normal-size wheel well mean manufacturers can make room inside the wheel for larger brakes. Thin sidewalls are also stiffer and deliver better cornering and road feel. Let's not avoid the obvious thoughlow-profile tyres just look cooler than regular tyres.
When we say low-profile, we're talking about the size of the edge of the tyre. Read the numbers molded into the sidewall; the second number printed in the series is the aspect ratio, indicating sidewall thickness as a percentage of tread width. For example, a P225/45R15 tyre has a 15-inch wheel size with 225 mm of tread width, and the sidewall is 45 percent of tread width, or 101 mm. The higher the aspect ratio, the thicker the sidewall and the comfier the ride; lower aspect ratios lead to thinner sidewalls and a stiffer ride. There are drawbacks to this kind of rubber. tyres are a part of your car's suspensionthe sidewalls absorb some of the most vicious road imperfections. Unless the suspension has been designed to accommodate the stiffer sidewalls, it can mean a rougher ride. Blowouts (a hole in the tyre caused by road debris) shouldn't be more frequent than with normal tyres since the tread and ply construction aren't much different. Rapid deflation is something to be concerned about; hitting a pothole with thin sidewalls can damage the wheel. tyremakers constantly improve designs with more robust materials and construction, so newer tyres aren't damaged as often as old low-profile tyres.
If you're buying a new car for comfort, order smaller wheels fitted with larger-sidewall tyresthey'll offer a softer ride. Less aggressive shocks may help a bit but at the cost of handling. Beyond this, you're looking at changes to suspension hardware, which isn't for the faint of heart. You'll have a tough time finding parts anyway, as the aftermarket usually aims to make cars more rigid rather than pillow soft.
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