Tyre pressure

pgj2015

What psi would you out in 195/65/r15 tyres?

AndyBoBandy

https://www.boards.ie/discussion/2058376967/tyre-pressure

depends on the car and its weight…

what does the door card say? (usually lists recommended tyre pressures)

pgj2015

3.4 bar but the tyres are supposed to be 205/65/r15

Alun

3.4 bar is very high, that's around 50psi! Are you sure it's not 2.4?

User1998

If in doubt anything between 30 PSI and 40 PSI will be fine

colm_mcm

what car is it?

pgj2015

actually yes, I says 2.4 bar.

I usually put 34 psi in but the tyres were wearing on the outside so was told my a mechanic to put 40 psi.

sundodger5

Why did you change the tyre size? Tyres also have a load rating and changing the size would possibly lower what that load rating is pkus the changes to how your speedometer reads. Plus upping the tyre pressure will not fix wear if it is one side of the tyre

pgj2015

https://www.boards.ie/discussion/comment/122745621#Comment_122745621

The tyre guy I bought tyres from said the ones on it were too wide and there was no need to have tyres that wide.

Atlantic Dawn

https://www.boards.ie/discussion/comment/122745642#Comment_122745642

What tyre sizes originally came on the car when new? Usually inside the fuel door, glovebox or drivers door pillar there will be a sticker indicating the sizes of tyre that the car came with and recommended pressures.

kirving

What car is it?

A 330e with a full boot at 5 passengers is supposed to have up to 51psi.

pgj2015

https://www.boards.ie/discussion/comment/122745683#Comment_122745683

Peugeot partner passenger car.

pgj2015

https://www.boards.ie/discussion/comment/122745668#Comment_122745668

205/65/r15

mickdw

https://www.boards.ie/discussion/comment/122745642#Comment_122745642

Sounds Like the tyre man wanted to sell what he had to hand.

They are only one step smaller but it will effect your speedo but not by alot.

2.4 bar is somewhere between 34 to 35 psi.

pgj2015

https://www.boards.ie/discussion/comment/122745725#Comment_122745725

He said the wider tyres were more expensive. ah its hard to know who to listen to, the mechanic said to put 40 psi in.

SVI40

https://www.boards.ie/discussion/comment/122745757#Comment_122745757

Listen to what the manufacturer says goes on the car. They have better idea than you tyre man.

sundodger5

Worked in tyres for years. Used to come across this often enough. Usually a case of selling what he had in stock rather than losing the sale.

Pay heed to the load indice as well, i would be a bit less concerned if the 195s have the same load indice as the original 205s.

Esel

Your speedometer will now read just 2% over your real speed, whereas on the original size it would be a higher margin.

Just be aware that you can't drive at an indicated 130 and assume you're only really doing 120 anymore!

Now, an indicated 123-124 wil mean you are doing 120 actual.

See

https://tiresize.com/

pgj2015

Maybe I should go back to 205s? even though i have been driving on the 195s for years and never got a speeding ticket.

mickdw

https://www.boards.ie/discussion/comment/122746471#Comment_122746471

They have fitted a smaller rolling radius tyre so for any indicated dash speed, they will be moving slower than they originally were.

Esel

https://www.boards.ie/discussion/comment/122746913#Comment_122746913

From that website

mickdw

https://www.boards.ie/discussion/comment/122747266#Comment_122747266

You are not interpreting it correctly.

It assumes original reading is exactly right so on the original tyre, they assume 100km per hour dash display is 100 km per hour actual speed. The revised smaller radius tyre results in 100 km per hour dash display being a slower actual speed.

If.the dash over read to start with, you.would have the situation for example of 110kmh display being a true 100 originally. Now being on smaller tyre 110kmh display becomes a true 98.

Esel

I understand, thanks.

Good site all the same (if you can interpret it correctly)! 😀

User1998

Just use Google Maps/Waze and compare it to your speedometer

Stephenc66

A quick Googe appears to show a 195/65 R15 as being an option on a Peugeot Partner and 2.4bar/34psi being the correct tire pressure.

A rule of thumb is if the tires are wearing both the outside edges excessively, they are under inflated if they are wearing the centre excessively, they are over inflated.

It appears from what you say the mechanic is suggestion they are underinflated hence the suggestion to go to 40psi which appears a big jump.

If it were me I’d set the tire pressures when the tires are cold and keep increasing by 2psi until there is a change in tire wear pattern. Remembering over or under inflated tires can cause handling problems especially under heavy braking.

From my own experience as an example, similar but different my VW Touareg eats the centre out of tires at factory settings but re-setting them to factory settings when hot has cured this and the pressure is lower now when cold and it is these pressures I set the tires to when cold.

In the case of a tire wearing on one side of a tire more than the other it usually points to badly aligned steering or suspension geometry. If this is happening with you then maybe your car needs a four-wheel alignment.

Hope this helps

Dex Dexta

Use the “4 psi rule-of-thumb”. Tyres should rise by 4psi from cold to hot. Stick 33psi in them cold, go for a spirted drive to get tyres hot, then measure. If the rise is less than 4 add air - if greater than 4 then deflate.

pgj2015

https://www.boards.ie/discussion/comment/122748643#Comment_122748643

I was putting 34 psi in the tyres. it was the 2 left tyres that wore on the outside. I got the tracking done a few months ago (seems like only a few months ago) will check for the receipt. I will get the mechanic to put it up on the lift to see if there is any suspension parts broke.

mickdw

2 left side tyres wearing on 1 side is down to more than pressures.

The rear axles give bother on those resulting in uneven rear tyre wear

pgj2015

Should I go back to 34 psi?

Gooser14

https://www.boards.ie/discussion/comment/122750143#Comment_122750143

Do you rotate the tyres at set intervals. I rotate mine every 10000 km & end up with very even wear.

pgj2015

https://www.boards.ie/discussion/comment/122751556#Comment_122751556

no.

Dex Dexta

oops - I got that mixed up:

Use the “4 psi rule-of-thumb”. Tyres should rise by 4psi from cold to hot. Stick 33psi in them cold, go for a spirted drive to get tyres hot, then measure. If the rise is less than 4 then deflate - if greater than 4 then inflate.

Esel

https://www.boards.ie/discussion/comment/122751728#Comment_122751728

I think you got it right the first time?

Dex Dexta

I’m basing my edit on the thinking that a seriously under inflated tyre is more likely to blow-out due to the massive increase in pressure when it heats up?

Esel

There is no 'massive increase in pressure'. Your edit is still wrong IMO.

creedp

https://www.boards.ie/discussion/comment/122751795#Comment_122751795

Not a scientist but I don't think that is a definitive equation. All tyres increase in pressure when driven. As mentioned above there I'd no massive increase in pressure, irrespective of the cold tyre pressure. On the model 3 the tyres increase from 42psi to 44psi quite quickly - there is a constant readout on the screen. Similar increase on the Leaf from 40psi. Don't really know with the smax but they are inflated to 38psi cold. Never had an under/over inflation issue with tyres.

pgj2015

What does it take to heat them up? If you drove at 80 km per hour fir 10 minutes to get to the petrol station, would that heat them up?

Dex Dexta

About half an hour at 120 this time of year or say 20 mins in summer

Esel

https://www.boards.ie/discussion/comment/122753177#Comment_122753177

That would mean you drove nearly 28km round trip to check your pressures…

Buy a pressure gauge a good 12V compressor and do it anywhere - also, you will be able to re-inflate a flat tyre enough to get you home or to a garage/tyre shop if the puncture is not severe, which will mean not having to fit the spare wheel with the extra effort and risk that is involved in doing that.

It's easiest just to get in the habit of checking pressures when tyres are cold.

Dex Dexta

If you keep your vehicles as long as I do (26 yrs and 21 yrs with 2 of them here) it’s a good investment long term. (Do it in conjunction with a trip).

The point is you will know the optimum cold pressure using the 4 psi rule - stickers are unreliable/ a good starting point - car makers buy them by the millions.

Esel

https://www.boards.ie/discussion/comment/122753951#Comment_122753951

Your sticker statement is ludicrous.

Dex Dexta

Hyperbolic perhaps, but ludicrous? - hardly.

Esel

https://www.boards.ie/discussion/comment/122754435#Comment_122754435

I'm not changing my statement for any hyperbolics.

pgj2015

https://www.boards.ie/discussion/comment/122753635#Comment_122753635

I would be going into town anyway. not especially to check the tyres. have a good gauge bought lately.

Esel

https://www.boards.ie/discussion/comment/122754566#Comment_122754566

All you need is the compressor then. Lidl had a good one recently. Ring their customer care and they could say if store(s) near you still have them in stock.

Budget for about €20-€25 cost.

Believe me, you'll wonder why you didn't buy one earlier.

Stephenc66

https://www.boards.ie/discussion/comment/122750143#Comment_122750143

https://www.boards.ie/discussion/comment/122750433#Comment_122750433

I'm with mickdw on this one. Especially the back axe issues, I'd be starting there.

Charles Babbage

https://www.boards.ie/discussion/comment/122753635#Comment_122753635

This. I had a puncture at the weekend, I used my 30 year old pump that my dad gave me as a present and a pump was good for 5km or so. I initially used it to get home, then on Monday a couple of pumps brought to a neighbouring town, without any need to change the wheel. Worth it for that alone.

chooseusername

https://www.boards.ie/discussion/comment/122750143#Comment_122750143

Too many roundabouts on your commute to and from work.

You have Milton Keynes tyres.

User1998

https://www.boards.ie/discussion/comment/122758714#Comment_122758714

Same, I haven’t changed a tyre in years. I just pump the tyre to 45 PSI and drive straight to the tyre shop. Worked a treat this morning when I came out to a flat tyre after buying part worns yesterday. Tyre was still fully inflated when I arrived at the tyre shop.

Charles Babbage

https://www.boards.ie/discussion/comment/122759222#Comment_122759222

There is a previous post from me somewhere about this. I had a puncture on New Year's Eve, on the same tyre as it happens, a tyre now gone. I got home with a few pumps and changed the wheel for the space saver the next day in daylight, as it wasn't a great day for getting work done. Going home was still worth it and even if I had been far from home a pump would have brought me to a more convenient place to change the wheel.

mickdw

Punctures are a rare occurance now anyway.

Still not too pleased that my new car came without a tyre or inflator kit.

Pirelli seal inside tyres..... but I wouldn't have great faith in that system.