Tyre pressures

Post by **smashymike** » 23 Nov 2004, 00:49

Xantia TD (95N), Xsara LX (Xreg) - both running Michelin Energys at 33/31psi & 2.4/2.3bar (whatever that is in psi!), my question is am i ok in running these pressured down a few pounds as the ride on both cars is quite hard. Are these pressures right? They are whats on the door column inside, could they be wrong?

David W · Post by **David W** » 23 Nov 2004, 01:03

Those tyre pressures are right, this is typical of the hardness many experience with these Michelin tyres.
A "few" pounds down will possibly increase edge wear and is not ideal at motorway speeds.
Having said that in my experience the average car/driver runs a few pounds down most of the time.
David
David

np · Post by np » 23 Nov 2004, 02:52

I recently upgraded my tyres from 185/65/15`s to 205/60/15`s.My pressures for normal use on 185 tyres are 33 psi frnt,30 rear.For estates with the 205 tyre,they are 35 psi frnt,33 rear.I put these pressures in the new tyres & the car was all over the place,didn`t feel safe.Put the pressures back the the figures for the smaller tyres with no more problems.I think alot of it is down to try`ll(?) & error.Hopefully no error.

jeremy · Post by **jeremy** » 23 Nov 2004, 03:26

Mike - what gauge are you using? I often check my tyres using a footpump with gauge on it. Nice and easy - blow them up till the needle is on the tell-tale - or so I thought. then one day I checked them with a pencil type gauge - they were about 4 psi over pressure!
Which one is right - having now used 2 pencil type gauges giving similar readings I'm inclined to trust them - I suppose I will now have to sample garage gauges and compare!
At present I use the pencil type gauge pressures and have checked to make sure nothing is running hot.
What is interesting is that Citroen never quote a heavy load or fast running figure.
Jeremy

np · Post by np » 23 Nov 2004, 03:51

I always use a Michelin foot pump,as tested by Auto Express,as it was the most accurate.

P 2501 · Post by **P 2501** » 23 Nov 2004, 12:48

Some footpumps have a better quality gauge than others and are more accurate. I have a cheapo pump with a really inaccurate gauge and i have got into the habit of checking with a pencil type gauge, and i find these to always be accurate.

mipster · Post by **mipster** » 23 Nov 2004, 19:10

<I>I always use a Michelin foot pump,as tested by Auto Express,as it was the most accurate.</I>
I bought a Michelin foot pump recently after destroying 2 cheap ones.
Used it to adjust the pressure on all 4 tyres after rotating the wheels.
But when I checked the pressure using a accurate guage all 4 where too high; tried it since and it's constantly 10% or more out - even borrowed a pencil guage which agreed with my dial guage.
BTW On my xantia the a 3psi difference on the rear tyres can cause a vibration like a wheel imbalance.
mipster

bxbodger · Post by **bxbodger** » 23 Nov 2004, 19:41

I actually run my BX fronts a few pounds OVER. I have a base spec diesel with <b>no power steering!!!!</b>[:0]
It doesn't seem to make any difference to rid, handling, or wear rates, just makes tight parking a bit easier.

Kowalski · Post by **Kowalski** » 23 Nov 2004, 21:19

Running underpressure can make your tyres overheat (possibly to disintegration), makes the tyres distort more under cornering, increases fuel consumption and decreases wet weather performance but it will improve comfort. Running tyres over pressure won't cause as many problems as running underpressure, it tends to make the ride hard and can make it a bit bouncy since your tyres aren't as damped as your suspension is.
If you start with over pressured tyres and lose pressure, you are better off than starting off with underinflated tyres and ending up with very underinflated tyres.
Its really best to run your tyres at the correct pressure, that way they have the characteristics that the car's suspension was designed for and their will wear evenly.

Post by **smashymike** » 23 Nov 2004, 22:53

Thanks all. Seems like i'd be better leaving things 'as-is'. As for gauges, the problem really started when i'd been using a cheapo footpumps gauge thinking all was well. Bought a SykesPickavant round one and that read 6lbs under, oh dear!! So i put the extra 6psi in and it felt aaaaawwwful. So, what did i do but buy a 'stick gauge thinking (hoping) it would calibrate with my footpump but oh no, it only verified the dial gauge. So where do i go from here? I'm now used to a softer ride but should i risk putting pressures down? Maybe a couple of psi won't hurt matters eh!