Tyre Pressures - get 'em right!

[MarkCL]

All - I know this has most likely been posted a gazillion times before but I just thought it worth popping in a quick "reminder" thread about getting the tyre pressures right.

My car has just not feeling right in the handling and I've been meaning to check the tyre pressures for months now, but each time I've been in the garage and rememberd either the air pump has been occupied or broken :evil: Anyway, I remembered again yesterday and did them at home using a digital tyre pressue gauge and foot pump. Intial findings were that all four tyres were different pressures to start with LOL!

The result after having inflated them to proper values - almost like having a different car!! All pressures are now correct front and back and finally the car feels like it should - all the suspension parts etc working together and even braking feels better and more stable!

So - for just a small investment in time and effort I got my car riding like it should. Moral of the story - regularly check your tyre pressures and your car will thank you for it

Cheers,
Mark

 

[bigasotonuk]

Mark,
What pressure do you put in the C43?
As I can,t find it in the handbook, and the sticker in the fuel flap is wrong, it says the same as my handbook that the car had only 215 tyres on it all round. 215 being the winter tyre size.

 

[Aussie Nick]

I think the manufacturer's recommendation is based on a soft ride. I have pumped mine up to higher values for better handling and fuel economy. I am aware that overinflating can cause the tyres to wear on the inside. However underinflating may cause scrubbing on the inside of the tyreface.
It is best to experiment until the correct tyre pressures are discovered.

 

[David Nock]

Tyre Checks - Once a fortnight and always before a long fast motorway type run.
A home footpump and good pressure guage is essential.
Your tyres will repay your outlay with greatly extended tyre life, you will get a bit of excercise pumping away and your own life might be extended as well.

 

[vijilants]

I use one of those michelin 12v tyre inflators.

Must be the best gadget Ive ever bought.....no more trips to the petrol station to use a seriously battered and inaccurate guages, and no more queueing.

I would highly recommend one of these !!!!!

http://www.autoexpress.co.uk/products/products/218223/mini_compressors.html

 

[MarkCL]

Andy - at the mo I'm running 34psi in the rears and 30psi in the front, but as Aussie Nick has suggested, it's really a question of experimentation of higher & lower pressures till you find a setting thats just right for you. So far all I do know for sure is that the way I have it currently set is far better than it was

After some monkeying around on my GT-Four I ended up with two settings that worked well for me - 34psi all round and 36psi all round (235/45 tyres, 17 inch wheels all round and 4 wheel drive). The latter worked best for track days and rolling road sessions whereas 34psi was the best for everyday fast road - hence my choice for the rears on the C43 Originally I was thinking about putting 32psi in the fronts and this will be something I'll try out in a week or two just to see how that feels once I've gotten used to this setting. I'll post up findings of my experiments if you're interested? There might even theoretically be some positive gain in mpg, though it will be pretty small I imagine

Cheers,
Mark

 

[jubhi]

Should you still regularly check tyre pressures if you have the "Tyre Pressure Loss Warning System" ?

Just that I would assume the computer would flag up when tyre pressure has been lost and so have therefore not checked my prressure in at least 3 months...

 

[tromppost]

Tyre Checks - Once a fortnight and always before a long fast motorway type run.
A home footpump and good pressure guage is essential.
Your tyres will repay your outlay with greatly extended tyre life, you will get a bit of excercise pumping away and your own life might be extended as well.

Do not forget the spare, those that still have them!

 

[bigasotonuk]

Hi,
Many thanks Mark for your insight I,ll try as suggested 30 front, 34 rear.
I may even try 32 myself as I think I,m running 30 at the moment.

 

[jpbp200]

I've been running with a slow puncture for a little while now. (requires inflating every 10 days and only doing short runs into town etc so I'm not too bothered and funds are required elswhere!) However, it is certainly an interesting excercise in terms of experiencing different handling as the pressure deteriorates. The steering becomes sloppy and imprecise and 'wandering' in windy conditions is accentuated.

I would suggest that for normal use a visual inspection once a week is sufficient unless like me you have a problem then daily is obviously advisable. If you have tyre pressure warning it is worth bearing in mind that the system is not infallible so a periodic visual check is always in your best interest.

 

[David Nock]

Should you still regularly check tyre pressures if you have the "Tyre Pressure Loss Warning System" ?

Just that I would assume the computer would flag up when tyre pressure has been lost and so have therefore not checked my prressure in at least 3 months...

Maybe not in this case, but I'd certainly want to put the gauge on every month and look for tread damage etc.
Does the pressure loss system read overpressure? Because tyres inflate harder as the summer weather arrives and the ambient temp goes up.

 

[darrenb1707]

I've just fitted 19" alloys to my 2001 CLK 230K. I'm running 235x35s on the rear and 225x35s on the front. Anyone know what the recommended pressures would be?

 

[jubhi]

Maybe not in this case, but I'd certainly want to put the gauge on every month and look for tread damage etc.
Does the pressure loss system read overpressure? Because tyres inflate harder as the summer weather arrives and the ambient temp goes up.

Hi,

I don't believe it does advise of overpressure. Once you have inflated the tyres to the correct pressure you are supposed to reset the system via the dash computer and then the system re-calibrates whilst driving over a certain number of miles and then once any pressure loss is detected it informs you exactly which tyre to check etc...

 

[hawk20]

Hi,

I don't believe it does advise of overpressure. Once you have inflated the tyres to the correct pressure you are supposed to reset the system via the dash computer and then the system re-calibrates whilst driving over a certain number of miles and then once any pressure loss is detected it informs you exactly which tyre to check etc...

Yes. But you need to lose a fair amount of air before it registers so regular checking is still in order.

Talking of cars wandering when tyres are inflated wrongly, Micheldever (who are huge tyre suppliers to MB dealers and others) have found that on some Mercs if you put different tyres front and rear it can seriously affect handling. Different makes have different wall stiffness and so lean is greater or lesser depending on make. C class especially susceptible apparently.

 

[television]

I think the manufacturer's recommendation is based on a soft ride. I have pumped mine up to higher values for better handling and fuel economy. I am aware that overinflating can cause the tyres to wear on the inside. However underinflating may cause scrubbing on the inside of the tyreface.
It is best to experiment until the correct tyre pressures are discovered.

Sorry to nit pick,, over inflation wears the center of the tyre

 

[grpar]

Couldn't agree more about stepping up the pressure above the recommended norm.

Can't remember who suggested it a few weeks back on a different thread, but on my 54 C-class I've put the fronts to 32/33 and the rears to 35 and the car behaves markedly better.

 

[hawk20]

Sorry to nit pick,, over inflation wears the center of the tyre

Quite right, as the tyre goes slightly rounded in cross section instead of flat on the surface. Similarly under-inflating wears the sides of the tyres (instead of being flat, the surface goes slightly concave).

 

[whitenemesis]

Couldn't agree more about stepping up the pressure above the recommended norm.

Can't remember who suggested it a few weeks back on a different thread, but on my 54 C-class I've put the fronts to 32/33 and the rears to 35 and the car behaves markedly better.

Those are within the "normal" recommended pressures for my car...

 

[Mr Teddy Bear]

I've just fitted 19" alloys to my 2001 CLK 230K. I'm running 235x35s on the rear and 225x35s on the front. Anyone know what the recommended pressures would be?

I have a 98 clk 230 sport kompressor i've just fitted new [to me] 17" AMG's with 225x45 front and 245x40 rear got 32psi front and back at present however will keep this thread updated after doing some research!

 

[grpar]

Those are within the "normal" recommended pressures for my car...

Sorry Whitenemesis, I should have been clearer. When I said "recommended" norm I was referring to the sticker on the inside of the petrol cap. 30F and 33R are the typical values, although it seems you can go as high as 41 psi on the rear if you're carrying heavy loads. Does the mother-in-law constitute a wide or heavy load, I wonder ?