Tyre Pressures?

Swedish Mike

Swedish Mike

New Member
Hi,

I have 205 45 r16 tyres on my 1.4l petrol car. Can anyone please suggest pressures for mainly in town driving with 2 passengers and little load. Bar or psi works.
Cheers Mike 😊
 
I would suggest you won't go far wrong with between 32 to 35 psi all round but it's a little bit of personal preference.

I would personally go with 32 psi all round as the 1.4 petrol is fairly light and see how you go.

For reference I'm currently running 35 psi all round on our slightly heavier TDI 75 wearing slightly oversized 185/55/16 tyres.

Hope that helps a little 👍
 
Thank you. It does. Just changed to summer tyres and the tyre fitter had issues understanding that an A2 is so light.
 
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As you can see in the below chart, 205/45R16 has a higher standard load index than the standard A2 tyre sizes. This means that 205/45R16 tyres don't need as much air pressure as the standard tyre sizes.

Standard Load Index
175/60R15 81(462kg)
185/50R16 81(462kg)
205/40R17 80(450kg)
205/45R16 83(487kg)

For "town driving with two passengers and little load". I would try 32psi front/29psi rear, and then a slightly softer 29psi front/26psi rear.

However, adding two or three rear passenger and perhaps some heavy luggage in the back of the car, requires a big increase in tyre pressure...at least if you are going to be driving at high speed.

So 29psi front and 26psi rear could become 32psi front and 35psi rear when a lot of weight is added in the back.

For 205/40R17 tyres, a heavily loaded car might have 35psi front and 38psi rear. This allows the front tyres to support a weight of 720kg, and the rear tyres to support a weight of 780kg, ie. a total weight of 1,500kg.

According to wikipedia, the maximum kerb weight of the A2 is 1,030kg. So tyres that are inflated to support up to 1,500kg, provides for up to 470kg of load. If you had five passengers including driver weighing 75kg each, that's 375kg. So that 470kg is looking like plenty of tyre pressure for adding some luggage in the back as well.

Minimum tyre pressures are based on maths.

Maximum tyre pressures are based on owner's preference. Over-inflating tyres makes the ride harder. Although higher tyre pressures can make the steering and handling sharper. However, even on tyrereviews where they spend much of their time trying to shave one second off their lap times while testing around a race track, I doubt they over-inflate much.
 
Last edited:
carlston said:
As you can see in the below chart, 205/45R16 has a higher standard load index than the standard A2 tyre sizes. This means that 205/45R16 tyres don't need as much air pressure as the standard tyre sizes.

Standard Load Index
175/60R15 81(462kg)
185/50R16 81(462kg)
205/40R17 80(450kg)
205/45R16 83(487kg)

For "town driving with two passengers and little load". I would try 32psi front/29psi rear, and then a slightly softer 29psi front/26psi rear.

However, adding two or three rear passenger and perhaps some heavy luggage in the back of the car, requires a big increase in tyre pressure...at least if you are going to be driving at high speed.

So 29psi front and 26psi rear could become 32psi front and 35psi rear when a lot of weight is added in the back.

For 205/40R17 tyres, a heavily loaded car might have 35psi front and 38psi rear. This allows the front tyres to support a weight of 720kg, and the rear tyres to support a weight of 780kg, ie. a total weight of 1,500kg.

According to wikipedia, the maximum kerb weight of the A2 is 1,030kg. So tyres that are inflated to support up to 1,500kg, provides for up to 470kg of load. If you had five passengers including driver weighing 75kg each, that's 375kg. So that 470kg is looking like plenty of tyre pressure for adding some luggage in the back as well.

Minimum tyre pressures are based on maths.

Maximum tyre pressures are based on owner's preference. Over-inflating tyres makes the ride harder. Although higher tyre pressures can make the steering and handling sharper. However, even on tyrereviews where they spend much of their time trying to shave one second off their lap times while testing around a race track, I doubt they over-inflate much.
Click to expand...
Thank you for such a comprehensive answer. 😊👍🏻
 
carlston said:
As you can see in the below chart, 205/45R16 has a higher standard load index than the standard A2 tyre sizes. This means that 205/45R16 tyres don't need as much air pressure as the standard tyre sizes.

Standard Load Index
175/60R15 81(462kg)
185/50R16 81(462kg)
205/40R17 80(450kg)
205/45R16 83(487kg)

For "town driving with two passengers and little load". I would try 32psi front/29psi rear, and then a slightly softer 29psi front/26psi rear.

However, adding two or three rear passenger and perhaps some heavy luggage in the back of the car, requires a big increase in tyre pressure...at least if you are going to be driving at high speed.

So 29psi front and 26psi rear could become 32psi front and 35psi rear when a lot of weight is added in the back.

For 205/40R17 tyres, a heavily loaded car might have 35psi front and 38psi rear. This allows the front tyres to support a weight of 720kg, and the rear tyres to support a weight of 780kg, ie. a total weight of 1,500kg.

According to wikipedia, the maximum kerb weight of the A2 is 1,030kg. So tyres that are inflated to support up to 1,500kg, provides for up to 470kg of load. If you had five passengers including driver weighing 75kg each, that's 375kg. So that 470kg is looking like plenty of tyre pressure for adding some luggage in the back as well.

Minimum tyre pressures are based on maths.

Maximum tyre pressures are based on owner's preference. Over-inflating tyres makes the ride harder. Although higher tyre pressures can make the steering and handling sharper. However, even on tyrereviews where they spend much of their time trying to shave one second off their lap times while testing around a race track, I doubt they over-inflate much.
Click to expand...
For clarification and to avoid any confusion, all tyre sizes are available in different load ratings not just one, so the load ratings quoted aren't specific to the sizes quoted and you need to check the correct load rating for that size of tyre before buying them. In other words it's the load rating (81, 83, 87, 91 etc) for each specific size that determines its load rating and capability not the size of the tyre.

Also, as well as making the ride harder, over-inflating tyres too much can adversely effect handling and grip rather than improving it and also increase stopping distances when braking (particularly in the wet) as well as causing potential damage to suspension components too.

Positives of increasing tyre pressures slightly are you will achieve better mpg due to less rolling resistance as well as prolonging the tyres life due to less scrubbing of the shoulders especially when turning and under-inflated.

I personally never inflate tyres to the minimum recommended rating as who knows when you will have additional passengers in the car or have a load in the boot (grocery shopping for example) and you can't be altering the pressures every time you use the car. I tend to go with somewhere between the minimum and maximum to cover all eventualities as I would much rather have slightly more air in the tyres than not enough 👍
 
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