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Daveg

Tyre pressure

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On my Passat there are 2  sets of tyre pressures on label displayed 

(2 people in car  and 5 people in car .) The latter has pressures  about 10 psi more . Question is what do I set them at for 2 people plus caravan ? I have decided on the 5 people set up , however I don't want the fuss of letting air out when I'm without van . Any thoughts 

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If you’re towing a caravan set them to whatever the highest pressure is no matter how many people are in the car

Don’t bother letting them down again whilst you’re on site, the ride may be a little firmer but don’t stress out about it.

Edited by Borussia 1900

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That is what I've done . So when  holiday is over would I need to reduce pressure . ? Seems a bit of a hassle ( away with caravan every month ) 

 

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10 minutes ago, Daveg said:

That is what I've done . So when  holiday is over would I need to reduce pressure . ? Seems a bit of a hassle ( away with caravan every month ) 

 

Daveg, definitely put the pressures back down to ‘normal’ when driving solo as over-inflated tyres are as dangerous as under-inflated ones - there’ll be less contact area and less stickyness (technical term:)).

 

Mine vary by just 5psi, but I inflate them before towing and deflate on arrival, then re-inflate before the journey home.  I have both pressures marked on the gauge.

 

John

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I use the higher pressure ( for 5 people)  and leave them at that year round

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9 hours ago, Daveg said:

That is what I've done . So when  holiday is over would I need to reduce pressure . ? Seems a bit of a hassle ( away with caravan every month ) 

 

 

You should be checking/adjusting the tyre pressures at least that often anyway

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I'm one of those who increases the pressure when towing, then drop it down to normal when the van's sited. Letting air out is quick and easy. Its the remembering to get the compressor from underneath the boot floor before packing up that I seem to have an issue with 😁

 

  • I agree completely 1

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I’m in Spain at the moment, my towing pressures are over 1 bar more than normal driving and they get left at that pressure whilst we’re here. Done lots of solo driving here on baking roads and heavy rain, apart from a harsher ride I’ve not noticed any significant difference in handling or braking.

If I tow at the lower pressure it is very noticeable.

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43 minutes ago, Borussia 1900 said:

I’ve not noticed any significant difference in handling or braking.

 

Of course not, you will only really notice on the day you need 100% !

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The two Passat's I had were on 235/45x17 tyres.

 

When towing we were nearly always just two of us with nothing heavy in the boot.

 

When towing I always felt that the fully loaded 10psi extra figure was too high for just an increase of 85kg nose weight.

 

Then 10PSi figure is designed for 3x75kg passengers in the back seat and 200kg of boot luggage.

 

I found the best balance when towing with a lightly loaded Passat was an increase of 5psi which I was happy to leave at that through our time away.

Edited by logiclee

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You’ll also get better fuel economy at the higher pressures. 

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Volvo prints an "ECO" pressure on the table of pressures inside the door, for my car this is 39 PSI and is the same as the "Fully Loaded" pressure; so I run this for all situations.

 

I ran my previous car at the recommended solo/2 people pressure for normal driving and the front tyres exhibited wear consistent with under-inflation. 

Edited by Custard Avenger

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If the OP reads the handbook he will find that the pressures are 36psi all round and 38/44 fully loaded. There is also a comfort setting of 33psi all round which makes a huge difference

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27 minutes ago, Woodentop said:

If the OP reads the handbook he will find that the pressures are 36psi all round and 38/44 fully loaded. There is also a comfort setting of 33psi all round which makes a huge difference

It depends on year with the Passat (And tyre size)

 

My B6 just had 33psi for 2 people and 44psi fully laden.  My B7 had 33psi 2 people, 44psi fully laden and 36psi Eco.

But now the newer cars have 36psi as the 2 people setting with 33 as "Comfort".

 

I suspect there will be some compliance issue with the emission test but  I found the difference between 33 and 36psi was negligible for economy but significant for comfort so 33psi was what I ran at.

 

Lee

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21 minutes ago, logiclee said:

It depends on year with the Passat (And tyre size)

 

My B6 just had 33psi for 2 people and 44psi fully laden.  My B7 had 33psi 2 people, 44psi fully laden and 36psi Eco.

But now the newer cars have 36psi as the 2 people setting with 33 as "Comfort".

 

I suspect there will be some compliance issue with the emission test but  I found the difference between 33 and 36psi was negligible for economy but significant for comfort so 33psi was what I ran at.

 

Lee

 

+1

Exactly my point.

It didn't help with the tyre size either.

The B6 was 235/45R17

The B7 was 235/40R18

The B8 is 235/45R18

The difference between 40 and 45 profile is very noticable both in comfort and handling.

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15 minutes ago, Woodentop said:

 

The difference between 40 and 45 profile is very noticable both in comfort and handling.

 

A little off topic here but tyre profile will be one of the reasons why some people are happy to run with higher pressure for a while and some wont.

 

I've been through a world of indecision earlier this year.

 

I wanted an XF but the years I was looking at had the following.

225/55x 17 Luxury

245/45x 18 Premium Luxury / R-Sport

245/40x 19 Portfolio

255/35x 20 XF-S

 

With a few options depending on year and a staggered option on high powered models.

 

The ride difference between the two extremes is night and day and I thought the 18's were the sweet spot.

 

I ended up with a Portfolio with 19's and 40 series tyres. Standard pressure is 33 which is fine on the open road but firm around town. Fully loaded pressure is 42psi but there's no way I'd drive around with that pressure in the tyres for a week or two. With a set of 17's and 55 profile tyres I dare say the higher pressure would be acceptable for a while.

 

Lee

 

 

 

 

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My Shogun has 265/60 R18 110V  Continental Sport Contact 5 SUV tyres on it and currently 3.2 bar in the fronts and 3.5 bar in the rears, a tad firm but it’s only for a couple of weeks

 

 

1B24F33B-E52D-4DF8-8C9A-D6E11388695F.jpeg

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Plenty of ground contact (only at the bottom though ;)) ‘stickyness’ has  remained unaffected. :)

 

48E2E00E-3CDD-41E9-AB7A-AED68AE426C7.png

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35 minutes ago, Borussia 1900 said:

Plenty of ground contact (only at the bottom though ;)) ‘stickyness’ has  remained unaffected. :)

 

48E2E00E-3CDD-41E9-AB7A-AED68AE426C7.png

 

A lot of sidewall there to cushion the extra pressure.

 

Although you may find that leaving the pressure up in something like this would be too much,

 

Not sure what year the OP's Passat is but it could well be on 40 profile tyres.

 

 

JAGUAR-XF-20”-Labyrinth-Front-ALLOY-AND-TYRE.jpg

Edited by logiclee

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15 minutes ago, logiclee said:

 

A lot of sidewall there to cushion the extra pressure.

 

Although you may find that leaving the pressure up in something like this would be too much,

 

Not sure what year the OP's Passat is but it could well be on 40 profile tyres.

 

 

JAGUAR-XF-20”-Labyrinth-Front-ALLOY-AND-TYRE.jpg

Yes, I can’t see there being much ‘give’ in those sidewalls

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Tyre pressures should be set when "cold"  i.e.  the ambient temperature.  A tyre pressure set at 20°C ambient will increase  by 2.2 psi when taken to an area with 35°C ambient temperature.

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32 minutes ago, beejay said:

Tyre pressures should be set when "cold"  i.e.  the ambient temperature.  A tyre pressure set at 20°C ambient will increase  by 2.2 psi when taken to an area with 35°C ambient temperature.

My 'Tyre Pressure Fault' Warning Light appeared last week just after 05:00 after leaving the Dieppe to Newhaven Ferry. Luckily, by the time I had remembered where the Menu was to clear the problem and had exhumed the footpump from the innermost depths of the caravan contents plus the kitchen sink in the back of the car, the tyre temperatures had cooled down to the ambient temperature ... :rolleyes:.

One day I'll surprise Mrs Marchie and get organised. My neighbour in France only speaks slowly enough for me to understand when he pops his head round the door of my 'workshop' - 'Quelle pagaille' ['What a shambles'] is a phrase I have heard often enough to memorise!

Steve

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7 hours ago, logiclee said:

The two Passat's I had were on 235/45x17 tyres.

 

When towing we were nearly always just two of us with nothing heavy in the boot.

 

When towing I always felt that the fully loaded 10psi extra figure was too high for just an increase of 85kg nose weight.

 

Then 10PSi figure is designed for 3x75kg passengers in the back seat and 200kg of boot luggage.

 

I found the best balance when towing with a lightly loaded Passat was an increase of 5psi which I was happy to leave at that through our time away.

My tyres are same and thats exactly what ive done ( split the difference) and it seems ok . You would think the labels would give a towing pressure recommendation , not just 2 passengers or 5. !

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44 minutes ago, Daveg said:

My tyres are same and thats exactly what ive done ( split the difference) and it seems ok . You would think the labels would give a towing pressure recommendation , not just 2 passengers or 5. !

 

VAG would say they give you a range from lightly loaded to fully loaded.

 

Then it's upto the driver to manage the tyre pressure between those figures depending on load.

 

It's difficult to manage a towing figure when it could be anything from a 300kg trailer for you tip rubbish or a 1800kg trailer maxing out the towing and noseweight limits.  Then are you towing with just a driver or 5 people and a boot full of luggage.

 

So a range of pressures is the best they can do and the driver can make a judgement based on load and experience.

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The rear pressure isn't just about the weight on the axle - higher pressures will stiffen the tyre sideways which promotes good stability - the fronts may also need increasing despite no increase in load in order to retain tha handling balance.

 

In the absence of specific towing recommendation in the handbook, using the full load rating when towing is a good policy, even if the car is lightly laden.

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