Tyre Pressures

CrazyChemist_2

Hello :j

Had a set of 4 Dunlop SP30 175/70 R13 82T fitted to my Nissan Almera, which states on the inner door panel that for a 3 person configuration, the front tyres should be inflated to 32 and rear to 30. For a 5 person load, the front should be 35 and rear 38.

However, we will be making a 70 mile journey soon, and shortly after that a 200 mile trip and I have heard that tyre pressures should be increased for long distance journeys. There will be 3 occupants in the vehicle on both occasions so should I reset the car tyres pressures to 32 & 30 or increase these to the 5 person load pressures? Why should the tyres pressures be increased and wouldn't this lead to abnormal wear on the tyres if not enough weight in the car?

I am not too sure about increasing the pressures as I know that tyres to tend to heat up slightly and thus increase the tyre pressure further.

I normally use the 5-person pressures when city driving with one/two people in the car - is this ok or not?

Silent_Bob_3

I'd use the ones listed inside the doors but add 1 or 2 psi to those figures to aid better fuel economy.

CrazyChemist_2

wouldn't they heat up and expand during the jouney? Also if the pressures are too high couldn't the tyre have less tread in contact with the road?

Porker

If the pressure is too low, and youre driving at speed, the tyre wall will build up heat as it bells out to a D shape (if looking at it in profile), and this is where youre most likely to see a failiure, hence speed pressures are normally higher. Same with load, if the car is crushing the tyres and deforming the sidewall then heat will build up which could cause a failiure on the stressed part. Pressures are a trade off with contact area with the road - over inflated tyres will reduce the contact footprint and therefore reduce your ability to stop and steer.

CrazyChemist_2

my sidewalls seem to be bulging slightly but I'm unsure of whether this is normal... I currently have the 5-person load pressures but just 1-2 persons in the car usually.

tonys_3

I am surprised that there is so much of a difference between three and five people.However you should reduce the pressures when you no longer have
five on board since the difference in the two figures could invalidate your insurance in the event of a claim.

If you have a 2 litre Almera,then the pressure for motorway and long distance driving is 36psi all round according to http://www.thetyrepressuremonitor.com

averagepunter

tonys wrote:

I am surprised that there is so much of a difference between three and five people.However you should reduce the pressures when you no longer have
five on board since the difference in the two figures could invalidate your insurance in the event of a claim.

Is this true? Having incorrect tyre pressures could invalidate insurance? In that case, half the country are driving around with no insurance.

afbrown

Has anyone tried this method? Recommended by Which?!?

http://www.uniflate.com

I'm off to Europe next week for a long drive and this looks like a snap at £1.75p per tyre.

CrazyChemist_2

Nissan Almera Recommended Tyre Pressure
1.4 16v Equation 95 - Onwards 34 30 36 38

This is not convincing - why would I take their advice when my car side door panel says 32 and 30 for light loads and 35 and 38 for loaded/fast journeys?

So are there any concerns about driving long distance with 3 occupants but at the higher pressures (35 and 38)?

RaceyRichard

Why do you not just go and ask your local experts i.e. most places such as kwik fit will give free advice.

You will also have peice of mind who the info came from rather than relying on many different opinions.

Further more they know more than just about tyres,brakes and exausts!

They certainly saved my fiance and her mums life when they spotted a major problem which could have proved fatal with her mums car when she had a new exhaust fitted.

Thank you Kwik Fit in Kidderminster :A this has been the best FREE advice i have known of for a long time!

Silent_Bob_3

Obviously a good Kwik Fit then as most of them are rubbish and know less than blind man.