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 R16 option, 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.
Low profile tyres are often used in high-end, sporting vehicles.
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.
The Kumho Ecsta is an example of a very low profile tyre.
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.
Low profile tyres: the Nexen tyre with a 15 profile.
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 tyre pros and cons
When it comes to choosing low profile tyres, just as you would choose any other tyre, you need to consider the various positive and negative changes.
Low profile tyres advantages:
There are many low profile tyre pros to consider, including:
These tyres often look better, offering an aesthetic that many drivers appreciate.
The lower profile often means larger rims and wider tyres have to be used. This can be beneficial for braking and cornering on dry roads.
A lower sidewall also increases the rigidity of a tyre. This is especially important when cornering at high speeds, as well as smooth surfaces.
Low profile tyres offer better grip and, thus, better control and predictability. Side swaying is significantly less noticeable.
Low profile tyres disadvantages:
Likewise, low profile tyres are not without the share of cons, such as:
Low profile tyres offer a lower driving comfort. This includes mechanical (shock) comfort, as well as acoustic (tyre noise) comfort.
Lower sidewalls also increase rigidity, decreasing the cars evenness on rougher road surfaces.
An increased tread stiffness also means a smaller contact patch on uneven surfaces. This can hinder the tyre’s grip.
A lower profile tyre usually requires increased width, which generates additional noise.
You should also be aware that installing low profile tyres in cars which have not been adapted for stiffer wheels will have a negative impact on the suspension wear. Additionally, if you change the wheel diameter by more than 5 mm, you will also need to readjust the headlights.