Tyre Pressure

[Frugglymuggly]

Have Michelin 235/35 R 19 Crossclimate all round on my 2018 Octavia VRS diesel estate, and have had conflicting opinions for the correct pressure for normal everyday driving, ranging from 34 -39 psi. Can anyone help?

[Ootohere]

You know the weather, the road conditions and the weight / load in your car.

What feels right without being too firm.

Start with them at 39 PSI if you want, reset the TPMS and if you feel you want to let air out and checking the pressure and resetting the TPMS then do that.

[KenONeill]

32 minutes ago, Frugglymuggly said:

Have Michelin 235/35 R 19 Crossclimate all round on my 2018 Octavia VRS diesel estate, and have had conflicting opinions for the correct pressure for normal everyday driving, ranging from 34 -39 psi. Can anyone help?

There's usually a type specific sticker on the inside of the fuel filler flap.

[Stoofa]

Recently had Goodyear AS6's fitted - 235/35/19 - I run these at 40psi.

Edited 28 February, 2023 by Stoofa

[varooom]

Here you are from maintenance document

 

270kPa = 39PSI

290kPa = 42PSI

320kPa = 46PSI

 

Being 19 inch rubber they need the higher pressures for the sidewalls of course.

 

[Carlston]

235/35R19 are oversize tyres compared to the standard 225/35R19 tyre size.

 

Therefore Skoda don't list tyre pressures for the 235/35R19 tyre size.

 

However, comparing the load indexes of the standard tyre sizes with the load index of the oversize 235/35R19 tyre size you can estimate suitable tyre pressures.

 

Out of the four 205/50R17, 225/45R17, 225/40R18, and 225/35R19 tyre sizes, 225/40R18 has the closest load index to the oversize 235/35R19.

 

Estimated tyre pressures for the oversize 235/35R19 tyre size with the car half loaded

2.4Bar (35psi) front tyres

2.4Bar (35psi) rear tyres

 

However, I would probably try somewhere between 2.4Bar (35psi) front and 2.2Bar (32psi) rear for a less than half loaded car with very little weight in the back and 2.6Bar (38psi) front and 2.8Bar (41psi) rear for a car loaded somewhere between half and full.

 

Edited 28 February, 2023 by Carlston

[varooom]

VW Golf, here they show the same pressure for 225/35/R19 as they do for 235/35/R19, with a different load index.

So I fail to see why this would differ from the above Octavia chart?

 

[Ootohere]

Is a Golf estate the same?  As it is I do not want high pressures with an estate car with nothing much carried, maybe not even passengers in the rear.  

[varooom]

5 minutes ago, toot said:

Is a Golf estate the same?  As it is I do not want high pressures with an estate car with nothing much carried, maybe not even passengers in the rear.  

My point was the 225 or 235 didn't change the pressure requirements.

 

Which suggests the original pressure table above is probably the same with a 10kPa difference is all.

[Carlston]

57 minutes ago, varooom said:

VW Golf, here they show the same pressure for 225/35/R19 as they do for 235/35/R19, with a different load index.

So I fail to see why this would differ from the above Octavia chart?

 

 

VAG do a huge number of tyre pressure charts with a huge range of tyre pressures, often changing inexplicably from one version of a chart to the next updated version of the chart.

 

It probably depends which young apprentice they've given the job to, as to what tyre pressures make it onto the white label that they stick under the fuel filler flap.

 

None of the recommended tyre pressures that VAG give on their white labels are likely to be underinflated, but many will be overinflated...especially when they group tyres with different load indexes together such as 225/35R19 and 225/40R18 which are four different load indexes apart, ie. 88SL/92XL versus 84SL/88XL.

 

Notice in the VW Golf tyre pressure chart above, that 225/40R18 is incorrectly shown as having a load index of 82. It's either 88 for the standard load index or 92 for the extra load index, with the 225/40R18 tyre size.

 

225/40R18 can support a 12% heavier load than 225/35R19 when inflated to the same tyre pressure, yet in the chart above they've inexplicably grouped them together.

 

However, VAG won't always be recommending tyre pressures just on load carrying capacity but on handling characteristics. For example, many drivers will have added 3psi to their front tyre pressures at some point from what the manufacturer recommends simply to sharpen up the front steering/handling.

 

Load indexes

84 (500kg)

88 (560kg)

92 (630kg)

 

By giving a range of tyre pressures according to load, it leaves it up to the driver to decide what they want to go with that day.

 

It's always best to overinflate rather than underinflate. So if you had a multidrop delivery job and loaded the car up fully at the start of the day and emptied it completely by the end of the day, you would probably want to go with the tyre pressures recommended by the manufacturer for a fully loaded car.

 

Many firms that use lots of vans such as Royal Mail will inflate for the maximum gross weight of the vehicle, even though most of the time they will be lightly loaded. This doesn't help driver comfort, who most of the time will be driving around with tyres that are pumped up far too hard for the load. The same applies to buses. If the bus is half empty, the bus' tyres will be far too hard for the load resulting in a harder ride for the passengers.

 

Edited 28 February, 2023 by Carlston

[varooom]

At this point I feel sorry for the OP, ask a simple question and get different answers.

Hopefully they found the sticker in the fuel flap or door frame by now.

[Carlston]

10 hours ago, Frugglymuggly said:

Have Michelin 235/35 R 19 Crossclimate all round on my 2018 Octavia VRS diesel estate, and have had conflicting opinions for the correct pressure for normal everyday driving, ranging from 34 -39 psi. Can anyone help?

 

Have you got a white tyre pressure label under the fuel filler flap?

 

Example of white tyre pressure label under the fuel filler flap

Edited 28 February, 2023 by Carlston

[KenONeill]

4 hours ago, Carlston said:

None of the recommended tyre pressures that VAG give on their white labels are likely to be underinflated, but many will be overinflated.

OK, now explain why Toyo Proxes T1-R in the standard 205/55R16W size give an underinflation wear pattern when running the recommended pressures of Octavia1 Elegance and L&K models (observations taken by several different drivers, using different actual cars, living in different counties). Is it possibly that you are speeling generalisations and not hard facts on tyres?

[Carlston]

22 minutes ago, KenONeill said:

OK, now explain why Toyo Proxes T1-R in the standard 205/55R16W size give an underinflation wear pattern when running the recommended pressures of Octavia1 Elegance and L&K models (observations taken by several different drivers, using different actual cars, living in different counties). Is it possibly that you are speeling generalisations and not hard facts on tyres?

 

It's a fact. If you got stopped by VOSA (or whatever they are calling themselves nowadays) and they found that your tyres were underinflated you would be for the high jump Ken.

[KenONeill]

6 hours ago, Carlston said:

 

It's a fact. If you got stopped by VOSA (or whatever they are calling themselves nowadays) and they found that your tyres were underinflated you would be for the high jump Ken.

You are just spouting legal generalisations.