PSI

MrLCA

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Afternoon all,

Obviously I don't know better than Mercedes but following the PSI guidance under the fuel filler cap leaves my tyres looking really flat. The temptation is there to pump them up some more...

I've tried two different pumps to make sure one wasn't under reading.

Screenshot_20210223-172723.jpg

According to this I should be 33psi front and rear. I am reading it correctly aren't I? I have 18" wheels and it's only myself in the car 90% of the time.

Any harm in going up a few psi?

Lawrence.
 

KillerHERTZ

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Over inflating will increase tyre wear slightly. If you pump them up only a couple PSI more you should be fine.
 

Gazwould

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I've been running tyres for 20 years a smidge over 40 psi , tyre wear is minimal and I've yet to experience center over inflation wear .
 

ChrisHGTV

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I find the fuel flap pressures too high on my S212 so I actually run them lower. I’m on 17’s though. Lower profile tyres can look semi-flat sometimes. I’m always checking my wife’s pressures on her Abarth as they always look flat!
 

Stocious

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Good point, not sure. I thought it was about best fuel economy?
No suspension and tyre rating and psi are stated with car full of occupants, full tank of fuel, and vmax speed, tyres get hot at very high speeds and pressures change, anyway like someone posted above over inflated a little is no great concern, it’s not like Mercedes are featherlight jap econoboxes where a little too much pressure would eat center of tyre away, under inflation is far more a concern as this will on anycar cause both outer edges of tyres to wear and increase fuel economy and after what I’ve said imagine the heat generated by an under inflated tyre on the autobahn, saying that I recently inflated mine fronts more than rears,in line with what my father thought me, one time 28 psi was the ballpark with the type of car I had and tyres, equally important is that there inflated equally side to side, all alloy wheels will loose a little over a long time as I was thought, run them at a higher psi and check often best practice, remember the nitrogen phase some time ago, forget what the benefits were, seen a video of a tyre being dismounted and a cabbage size cluster found inside as one of those puncture repair products had been used, you’d be shocked if you’d of seen, I’ll never use after seeing and not so long ago it was an option with a slow puncture I had, was leaking at the bead from corrosion of the alloy, to finish up allways but premium tyres, I’m on what came with mine which were 4 of the same unsure of quality, never heard of brand, but allways buy the best or your choice of the best, order online even and have them fitted at tyre shop, but insider tip they will curse you soon as your gone as you didn’t buy off them, I’m due a spell on a set of pirrelis I think next, soft but a good choice, tyre performance has increase substantially in recent years, can pay huge money for some, through work the amount of part worn winter tyres fitted to cars that are out of date is worrying, long winded but buy the best and keep uniformly inflated, if sustaining high speed and more so if heavily loaded pressures need to be adjusted to suit, all cars are made to be setup from factory to be full of people full of fuel and boot full too, that’s why they drive better with say a bag of coal in boot, I’ve even known people to have sandbags in there boots, makes short work of bothersome roads especially at speed, after thought towing has to be accounted for also, only the most performance orientated cars will have other specifications regards tyre pressures, corner weights and loading, corner weighted cars are a pleasure to drive when done correctly
 
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MrLCA

MrLCA

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Right. I've stuck 38 psi in all round. Will see how it goes. Steering feels quicker but may be a placebo. Have also noticed excessive wear on the outside and inside edges. Will get another few miles out of them and then time for a change to match the eagles on the rear.

Cheers for your opinions all.
 

markjay

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Right. I've stuck 38 psi in all round. Will see how it goes. Steering feels quicker but may be a placebo. Have also noticed excessive wear on the outside and inside edges. Will get another few miles out of them and then time for a change to match the eagles on the rear.

Cheers for your opinions all.

38 all around is what I would do as well.

2-3 PSI above the high figure is fine, and if the car isn't loaded I would keep the same pressure all around.

Inflation pressure on the high side will make for sportier ride, lower fuel consumption, and lower tyre wear. The only downside is (potentially) a harsher ride.
 

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