205/40/17 Tyre pressure?

[Mugen Civic]

Hi guys

Anyone know how much pressure to inflate a 205/40/17 tyre?

I used to always inflate about 30~32 PSI on stock 175/65/14
Issit the same?

Thanks

[trism]

i normally have my tyres at about 35psi

no matter the size

[magicmike]

should say what the recommended psi is on the tyre

if not usually 35-40

[SNKS2K]

doesn't matter what size the tyre is. the pressure is always the same.
keep it at about 35-38.

[JohnL]

should say what the recommended psi is on the tyre

if not usually 35-40

'Maximum' does not mean 'recommended'!

The max psi marked on the tyre is a max 'safe' working pressure at the maximum loading, and typically seems to be either 44psi or 51psi on passenger car tyres. I'm pretty sure that this isn't a number derived from destruction testing, but actually a rather arbitrary number arrived at from some 'approved' calculation involving various design paramenters of the tyre, the actual failure point will be way higher.

Rule of thumb for a starting point, try 10% below the 'max' marked on the sidewall, then experiment from there. There is no 'correct' psi for any particular tyre on any particular car for any particular driver prefference, though typically I think 32psi would be a bare minimum for adequate handling and steering response.

[Ry_]

I've got 205/40/17's.. They started out around 35-38 and last I checked they were 33-35. Was going to do a bit of highway driving over the weekend so I inflated them to 39-40 ish. I think anywhere from 35-40 is alright for mine, you know.. as long as it's not too close to the max psi.

[Mugen Civic]

okay
i'll try out 35 psi for today.
thanks guys

[VTi_b0i]

it says Max tyre pressure 44psi on them doesnt it? well mine does... i put bout 40

[02gzm]

The lower the tyre pressure the more grip you'll get but the more irregular wear will happen. Put lower pressure at the front and higher at the back to combat understeer ;)

[beeza]

I had 42 front and 40 rear on mine.Bit softer in the back for grip.

[dsp26]

for those who said anything below 38psi is giving poor advice.

should be around 40-42psi WARM for 205/40/17 as mentioned by some above

rough rule of thumb.. less sidewall = more pressure required

[beeza]

So true.I got 205/45/15's now and I'm runnin' 36 Front 34 Rear,again softer for the rear for more grip around dem' corners.

[dsp26]

this info is from people in the know.. remembered it since....



Tyre pressures should be at 36psi, not the 29psi and 32psi recommended on the tyre placard on the N14.

36psi is the required pressure for the proper 'footprint' of the tyre to be touching on the road, under-inflation causes the tyre to buckle and only the sides to touch, leaving the middle of the tyre not correctly in contact with the road.
The 29psi and 32psi listed on the N14, gives you a better ride quality, but compromises your safety / grip.
I've tested this theory as well, I find that the tyres roll a lot more when they are under-inflated, and grip is increased @ 36psi.
The ride is a little harder, but then its not that much difference.

Obviously some tyres have special requirements, especially in 4WD vehicals, but as a general rule its:
36psi around the city
38psi - 40psi for highway driving

(Source: Murcotts Advanced Driving Course)

Hope this helps



it all depends on tyre size as to what pressure to run, 36psi on 60 series tyres and above is far to much.

I am part of the dunlop motorsport team and fit tyres for all the kiwi v8's and they run between 21-24psi when inflated cold. as the tyre heats up it gets more pressure.

my standard rule of thumb is about 32-34 psi for every day driving with 60 series and above.
34-36 for 50-55 series tyres, 36-38 for 45 series tyres and 40+ for 40 series and below.
just look at a bmw tyre placcard, they run pressures like 44psi rear for a tyre like a 225/45x17 tyre. but they always wear the centre of the tyre if run at this pressure. hence a bit over inflated.



38psi is probably the tyre bead seating pressure for tyre fitters...

My GF's Civic has 42psi in her 17" Nankang NSII's!

I made the mistake of running 36psi in my 'XXXX' brand 18" tyres and within a few hundred kilometres, the had cracked the sidewalls from being crushed between the road and rim on bumps. I made a warranty claim and this certain tyre manufacturer refused and said they had heaps of claims because everybody under-inflates their tyres. Good for the tyre manufacturers pocket when I paid nearly $500 a tyre in 2003 and worst bit was, I got defected and fined by the cops for unsafe tyres!!

I changed brands at this stage and always keep my pressures above 40psi

[MZ3]

When i got my new tyres fitted 205-50 R17, they guy suggested around 38PSI. I've also been told if your running stock sized tyres and the side of the door says 30 or 33 or something.. a general rule is to go 10~15% above that since the pressures they suggest are aimed mainly at comfort rather than minimal tyre wear etc

[Mugen Civic]

wow great info, learning heaps about this,
i'm changing to 40 psi on my 205/40/17 and see how i'll go.