Tyre pressure when car is fully loaded on a long journey.

[chrisyork007]

Hi all, I will be crossing Europe soon and would like to find out the correct tyre pressure for my tyres. My car is 2013 Skoda Superb Estate 2.0 Diesel. We are going to be three adults and lots and lots of luggage, the car will be full to the top, but nothing on the roof.

I have looked at the guidance on my fuel lid, and there are some recommendations of a 3.1 BAR which I think is way too much. Please see picture below:

 

 

 

 

I am thinking of doing the front ones in 2.4 and the back 2.6.

 

Any suggestions would be appreciated.

 

Thank you.

 

 

[cnc]

Go with the recommendations - that's what it's there for. Wrong pressure with wrong circumstances = dangerous or possible catastrophic tyre failure. Which one you eventually go for will depend upon the weight of the people and weight of the luggage, so without wanting to sound rude if the combined weight of the three adults plus heavy luggage is above the average go with the higher pressure, lighter people with lighter luggage lower pressure.

Edited 3 August, 2014 by cnc

[Penpusher]

We go abroad with two people and luggage in the boot, but nothing apart from coats on the back seat, so I usually go halfway between minimum and maximum recommended pressures.

[KBPhoto]

Mines an Octavia not a Superb, but I always go up to near the recommended pressures (usually about 0.4-0.2 bar below the recommended pressure) on the rears and then drop them once I've unloaded.

 

That's with 2 adults up front, two growing children in the rear and a boot full of camping kit.

 

HTH

[chrisyork007]

Hi guys, thanks for the replies, I think I'll go with 2.4 front and 2.6 back.

[Stinker]

Many years ago I had the same dilemma. 4 adults and baby(all the baby stuff on board) going on holiday. Boot filled to the neck and roof box fitted and filled also. Car was passat 115 tdi estate. Filled tyres to the recommended pressures for full load as per sticker. Handling was seriously compromised. Very skittish. Lurched round corners. Pulled over after 10 miles or so and let a good slug of air out of each tyre. Problem solved. Maybe if you're carrying the car's max payload these pressures would be OK(2.4 and 3.1) but you'll probably find all your extra luggage weighs the same as one decent sized adult so really you're only carrying the equivalent of 4 or 5 adults.

What all that means is I think your in the right area although 2.4 might make the front skittish especially if the extra weight is in the back.

Hope this helps:-)

[Manatee]

One thing the manufacturers  aim to do with the tyre pressure recommendations is to maintain the handling balance.  I don't mean at the limit, just normal cornering balance for normal driving.

 

The handling balance alters with load because the weight distribution moves further back. Considering the starting recommendation of 3.1 bar at maximum load, you might reduce that a bit as you have only three passengers;  but the fully loaded boot will still have a more material effect because of the greater distance from the c of g than the back seat.

 

As the c of g moves backwards, other things being equal, the balance will move towards oversteer.  Note that I am not talking about what happens when traction is broken, just what is happening with slip angles at normal speeds. 

 

The correction for that is to increase rear pressures relative to the fronts, to maintain the normal and desirable degree of understeer.  You are not doing that by just adding 0.2 bar to each.

 

Erring on the high side with tyre pressures is usually better than being too low.  Personally I'd go a bit nearer the 'fully-loaded' figure for the rears anyway.  If you want to split the difference for the bit-less-than-full-load, then 2.3/2.7 would seem more proportionate.  Just increasing the pressures by the same amount front and rear will not correct the change in balance caused by moving the weight distribution rearwards.

 

Assuming of course that the car is standard and that all the tyres have near enough the same characteristics and state of wear, or all bets are off.

 

This is just my musing on the question - I claim no special insight or knowledge, and have never had a Superb.

 

Incidentally - here is the plate for the Roomster Scout 1.2 TSI on 205/45R16 tyres - going from part load to full load means a recommended increase in pressures of a mere 0.1 bar (front) and a massive 1.1 bar (rear - from 2.1 bar to 3.2 bar).  It's not mainly about load carrying, it's about handling is my conclusion from that.

 

Edited 3 August, 2014 by Manatee