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C4 - DS4 Owners :: Forums :: C4 Picasso and Grand Picasso - PRE 2013 only :: C4 Picasso and Grand Picasso General questions

C4GP and C4P Tyre Pressures

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fixerman   
Thu Apr 29 2010, 06:10am
Member No: #13128
Joined: Apr 01 2010
Location: London
BigJohnD wrote ...

snoopystorm wrote ...

I have just had new tyres put onto my car filled with Nitrogen curtosey of the workers at Kwik Fit, 5% better fuel economy, 5% better road handling and 25% more tyre life!! I don't know what pressure they are at now.

Yeah right. Don't forget regular air is 80% nitrogen any way!

Aircraft tyres are inflated using Nitrogen but as far as I know the reason is purely safety as pure Nitrogen is an inert gas and will not add to a potential fire resulting from an accident. Also it is less likely to alter in volume and pressure with changes in temperature.
Mark T   
Wed Jan 05 2011, 08:59am
Tyre pressures: Area of contact patch of tyre on road and deformability of tyre are reduced with higher pressures. So expect reduced dry grip and a firmer ride and better fuel economy if you run high pressures with light car load. Conversely, heavier steering, softer ride, increased fuel consumption with lower pressures. Outside manufacturer limits / uneven pressures expect to damage tyres and or car as you hit something, out of control. I normally run 3.2 Bar all round as often 5 or 6 people in car. Had new tyres fitted which fitter only put 30psi in and noticed big difference in handling / economy.
VTRPLUS27   
Wed Feb 22 2012, 05:29am
Member No: #24370
Joined: Feb 20 2012
Location: Hants
There is a problem here with the conversions, 2.4 bar equals 34.8 psi and not 32 as given in the tyre tables.
1 bar equals 14.503 psi.
Dave_Retired.   
Wed Feb 22 2012, 06:51am

Member No: #1
Joined: Aug 07 2006
Location: Northumberland
Use the conversion tool above that's what it's there for

Those label pictures are from Michelins site, and not what Citroen Engineers are recommending as per the 'A' pillar label on all UK models..
BigJohnD   
Wed Feb 22 2012, 07:08am

Member No: #82
Joined: Jan 22 2007
Location: Hoylake
I use the "Bar" settings as stated on the label by the driver's door hinge, as they'll be original Citroën measurements.
harry.potter   
Tue Apr 10 2012, 03:56pm
Have just changed from Premacy 215 R 55 16s to Vredestien after 30,000 miles
I checked pressure fortnightly and ran at the door-post labelled 35 psi.
At changeover I had more than 2.5 mm left but I wanted more in winter.
The outer tread was down to 1.5 but the centers were more all round.
I think that the 35 psi is too low as indicated by the wear pattern and am now running at 38 psi.
There does not seem to be any downside in performance. The noise is better.
And I got it done under £400 instead of £650. They are highly rated tyres and I'm happy
pedal   
Mon May 05 2014, 01:14pm
Member No: #503
Joined: Jun 27 2007
Location: Derby
I've posted this somewhere on the site before but I've consistently got better wear/more even wear by setting the pressure at 2.3bar and 3.1/3.3 when loaded for holiday etc and of course rotating the wheels every 10000mls. the higher settings tend to wear the centers more and the lower setting always wore the outsides more etc.
routemaster1   
Mon May 05 2014, 02:13pm
Member No: #574
Joined: Jul 08 2007
Location: Dorset
pedal wrote ...

I've posted this somewhere on the site before but I've consistently got better wear/more even wear by setting the pressure at 2.3bar and 3.1/3.3 when loaded for holiday etc and of course rotating the wheels every 10000mls. the higher settings tend to wear the centers more and the lower setting always wore the outsides more etc.

Which size wheels do you have. If I remember correctly the pressures vary quite a bit with size. 2.3bar is soft for the 215/50 R17 1 have. Rotation of wheels is no longer recommended, although I see no harm in it. However my experience is that the wear is almost the same on the front and the back, so is a waste of time and effort as 4 are required at the same time. And I dont seem to be able to get more than ~17000 miles on a set.
It is interesting that the same does not apply on our C3, which still has one original Michelin on the front which is getting very close to the end of its life at 37000miles (the other had to be replaced due to a bulging sidewall) but the rears are only about half worn.
FrankBullitt   
Mon May 05 2014, 03:10pm

Member No: #19238
Joined: Apr 12 2011
Location: Cambridgeshire
Yes, rotating isn't required - simply swap the backs to the front and put the new ones on the back although, as routemaster says, on the Picasso tyre wear us surprisingly similar both front and rear. I always kept ours at about 2.5 bar front and rear and 3.0 bar when loaded.
routemaster1   
Mon May 05 2014, 04:30pm
Member No: #574
Joined: Jul 08 2007
Location: Dorset
FrankBullitt wrote ...

Yes, rotating isn't required - simply swap the backs to the front and put the new ones on the back

I wouldn't bother with that either.
FrankBullitt   
Tue May 06 2014, 12:26am

Member No: #19238
Joined: Apr 12 2011
Location: Cambridgeshire
Not as the wear is the same on the Picasso but do otherwise - anyone whose ever seen what a part-worn tyre on a non-steering and unloaded rear wheel can do when lifting-off mid corner when there's a set of fresh tyres on the front would agree
routemaster1   
Tue May 06 2014, 01:19am
Member No: #574
Joined: Jul 08 2007
Location: Dorset
FrankBullitt wrote ...

Not as the wear is the same on the Picasso but do otherwise - anyone whose ever seen what a part-worn tyre on a non-steering and unloaded rear wheel can do when lifting-off mid corner when there's a set of fresh tyres on the front would agree

But on most cars where the fronts wear quicker, if you move them you finish with the worn ones on the back, which is the scenario you are describing. What I think you should do is leave them alone until the fronts need replacing, then new ones are fitted to the back.
FrankBullitt   
Tue May 06 2014, 04:27am

Member No: #19238
Joined: Apr 12 2011
Location: Cambridgeshire
routemaster1 wrote ...

FrankBullitt wrote ...

Not as the wear is the same on the Picasso but do otherwise - anyone whose ever seen what a part-worn tyre on a non-steering and unloaded rear wheel can do when lifting-off mid corner when there's a set of fresh tyres on the front would agree

But on most cars where the fronts wear quicker, if you move them you finish with the worn ones on the back, which is the scenario you are describing. What I think you should do is leave them alone until the fronts need replacing, then new ones are fitted to the back.



No, I'm advocating what you are describing - when replacing two worn front tyres, put the part worn ones from the back to the front and the fresh ones on the back. Always have the best tyres on the back.
DaveyP   
Tue May 06 2014, 05:12am
Member No: #34693
Joined: Mar 13 2014
Location: SW Scotland
Always have the best tyres on the back.


Errrrr....

In my short lived track experience (where I wanted to do three things... 1. Throw up, but doing that whilst wearing a full face helmet is not really an option. 2. Go home, but the big boys seemed kinda intent on forcing me to go in their general direction. 3. Win, came close a couple of times) if a rear didn't lift then you were not pushing hard enough, but on the Queens high way it sorta means you were pushing it harder than you should of been.

If there is a choice in the matter... IMHO better to have the steering end stay where one wants it and let the back take care of its self, rather than the other around.

So best on the front is my motto

Edit.. but I suppose that my way of thinking is because I know how to get the rear back in line without a panic attack... but once the fronts gone then life gets a bit harder,
pedal   
Tue May 06 2014, 05:29am
Member No: #503
Joined: Jun 27 2007
Location: Derby
FrankBullitt wrote ...

Yes, rotating isn't required - simply swap the backs to the front and put the new ones on the back although, as routemaster says, on the Picasso tyre wear us surprisingly similar both front and rear. I always kept ours at about 2.5 bar front and rear and 3.0 bar when loaded.


215/55 R16

I've had 3 GP's (all 1.6 VTR+ one manual then 2 EGS etc) first one i never kept long enough to notice the tyres etc, the 2nd one my primacy's were down to 3.5mm at 18k, my 3rd one i got the primacy's to 24k by playing with the pressures, since then I've only had Nokian wrg2 on my car, which to my amazement managed nearly 40k out of my first set (yes driven all year and lots of Spanish and south of France 35C+ weather) also grip better than the primacy's.

my Nokians are 215/55 R16 97V XL, which i run at minus 0.1 bar from the door panel figures
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