Tyre Pressures CLA

[Chelters]

Acquired a CLA 220 diesel new 63 plate with 225/40R tyres inflated to 230 kPa front and 210 rear by dealer. The fuel cap sticker instructs however pressures of 270 and 240. Which set of pressures is correct?

 

[turbopete]

this does seem odd. usually MB tyres are higher pressures at the REAR rather than the front

it could be, however that both pressures are correct. the dealer may have set the tyres for unladen/lightly loaded car and the pressures you quote are for a fully laden car?

 

[whitenemesis]

Maybe as the CLA is fwd the pressures are higher at the front?

I would go with the pressures stated on the fuel filler flap. It wouldn't be the first time a garage has got inflation pressures wrong.

 

[Chelters]

Yes I assumed it was higher for the front as it's Fwd
The fully laden sticker states 290 front and 280 rear which does seem high
The problem is that although v pleased with the car that branch of the dealership inspires me with no trust whatsoever

 

[JBell]

I would believe what the sticker says

 

[exjag]

It's quite a big difference, but couldn't be accounted for by discrepancy between your gauge and theirs I suppose? I have several different gauges and they all provide different readings. One mechanical one I bought recently, of a 'good make', read way above the others.

I've tried to find a way of checking gauges against a known standard, but have been unable to do so. Trading Standards don't do it.

 

[grober]

Many car manufacturers have started to increase their recommended tyre pressures in order to achieve better fuel consumption/ emission figures. This may be in excess of the pressures required for the adequate load carrying capacity of the tyre/vehicle in question. I would suggest seeking an opinion from a third party - the tyre manufacturer.

 

[toby1]

Go with the manufacturer. They built the thing!

 

[grober]

Go with the manufacturer. They built the thing!

They don't build the tyres. In the old days manufacturers used to publish recommended tyre pressures for a certain model in their car owner handbooks - not now. Now its only a sticky-on label on the fuel cap- why do you think that is?

 

[JBell]

They don't build the tyres. In the old days manufacturers used to publish recommended tyre pressures for a certain model in their car owner handbooks - not now. Now its only a sticky-on label on the fuel cap- why do you think that is?

Because it's easier to get too when checking the pressures?

 

[rhud]

Many car manufacturers have started to increase their recommended tyre pressures in order to achieve better fuel consumption/ emission figures. This may be in excess of the pressures required for the adequate load carrying capacity of the tyre/vehicle in question. I would suggest seeking an opinion from a third party - the tyre manufacturer.

This is exactly right and costs them nothing. But 38psi on the rear tyres of an A Class? Crazy.

 

[JBell]

38psi on the rear tyres of an A Class? Crazy.

That will give a nice ride!!!!!!

 

[rhud]

That will give a nice ride!!!!!!

Yes ridiculous. The A is never going to ride like an S Class,but with 29 all round its ok. However whenever I have a service they insist on whacking them up to 32/38!

 

[Chelters]

Yes tyre gauges give variable readings but I use an electronic one which I have calibrated against an accurate track bicycle pump (honest!)
It's my first outing on this forum and I'd like to thank you all for the advice