Tyre Pressure Conflicting Reports

[garyogden1957]

I know it could be dangerous with the wrong tyre pressures in your car buyt I am getting conflicting reports.

My question was inputted to National Tyres and Kwik Fits website where you enter your reg number. It came back as 32 front and 26 rear for a ford fiesta zetec diesel 1.6 - 195/45R 16.

I spoke to Ford and they said 32 front 34 rear.

On the passenger door well it say 33 for carrying 2 passengers. So I have put 33 in all round is this safe and why do websites dish out wrong/dangerous information?

 

[TimST2]

Go with what's written on the car.

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[garyogden1957]

Thanks

 

[TomsFocus]

33 all round sounds too high for the rears on a Fiesta unless you are loaded up with luggage and passengers.  Don't you find its a bit 'floaty' at speed on the motorway?  I'd double check the sticker in the car personally.

There is actually a safe 'tolerance' of tyre pressures which is why you find discrepancies between websites.  Some cars also list different pressures for 'comfort' and 'economy' (higher pressures give better economy but less comfort and vice versa) so it's always best to use the figures shown on your actual car.

[garyogden1957]

Surely 26 in rear is too low?

 

[garyogden1957]

Just spoke with Kwik Fit and they say always go with the info on the sticker on the car door-well. It says 33 so that must be right? I am still unsure so I will check the manual also.

 

[TomsFocus]

6 minutes ago, garyogden1957 said:

Surely 26 in rear is too low?

 

26 rear is right for normal load.  The rear end of a Fiesta is very light when empty.  If you regularly carry luggage or a full tank of fuel then raise it a bit.  Here are the figures from the manual:

[TimST2]

Totally depends on the model / tyre size. My Fiesta ST is 36F/26R on the stock 205/40/R17 Bridgestone Potenzas.

Out of interest I just tried some of the online tyre pressure calculators and they all came back with incorrect values...

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[garyogden1957]

I will stick with what the car door well sticker says for 195/45R 16 1.6 Diesel.

[TomsFocus]

43 minutes ago, garyogden1957 said:

I will stick with what the car door well sticker says for 195/45R 16 1.6 Diesel.

That's a pretty poorly designed sticker tbh! 

The 1.6 Diesel there is only relating to the 14 or 15" wheels above it (note the asterisk).  195/45/16 is 31 front & 26 rear for normal load on the sticker.  But that's even different to the handbook which suggests33psi front!  

[TimST2]

If it helps, here's what's written in my manual (the 1.6L Ecoboost entry certainly matches what's on the sticker on my ST).

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[TimST2]

If it helps, here's what's written in my manual (the 1.6L Ecoboost entry certainly matches what's on the sticker on my ST).

 

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For future reference, as we're not in the Fiesta sub-forum, these are the recommended Fiesta tyre pressures for the whole range from the 2016 manual that came with my ST...

[TomsFocus]

13 hours ago, TimST2 said:

For future reference, as we're not in the Fiesta sub-forum, these are the recommended Fiesta tyre pressures for the whole range from the 2016 manual that came with my ST...

Look at the one for the OP's car...it's different yet again, now 35psi front!   Though that's probably for lower emissions by 2016 tbf.

[TimST2]

 

 

 

Look at the one for the OP's car...it's different yet again, now 35psi front! [emoji38]  Though that's probably for lower emissions by 2016 tbf.

That's interesting - I hadn't realised they change tyre pressures to help meet emissions. By my school of thought tyre pressures should be set for maximum grip and also even tyre wear! Fit more efficient tyres to meet emissions sure but don't overinflate?

 

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[TomsFocus]

1 hour ago, TimST2 said:

That's interesting - I hadn't realised they change tyre pressures to help meet emissions. By my school of thought tyre pressures should be set for maximum grip and also even tyre wear! Fit more efficient tyres to meet emissions sure but don't overinflate?

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Why would manufacturers care about tyre wear?  It's a consumable part that isn't covered under warranty.  And as long as they can meet the regs for braking distances they won't be after maximum grip either, more grip just wastes fuel and creates more emissions.

You'll find most tyres fitted to modern 'eco' cars are low profile and thin in width as well as being a slippery compound.  Boosting tyre pressures and giving a rock solid ride is just another way to improve efficiency...