Tyre pressure - How much

[astina]

[color=#FF7F00:post_uid0]hey ive got kumho 205/40r17 zr712 tyres and just wondering what would be the best pressure to have them at? i think the guy said 40psi.[/color:post_uid0]

[Toyboy]

[color=#000000:post_uid0]Yeah dude when i got my 18's the tyre place told me to run no less than 40psi,he said it also applied to the 17's :cool:
Which would explain why the edge of my tyres wore out more than the rest of the tyre when i had my 17's,cause i used to only run 34psi in them :(

Cheers :D[/color:post_uid0]

[mrpayner]

[color=#000000:post_uid0]I remember when I got my FM-901's put on in 205/50x15, the dude said to run them on 40psi too. I thought it was unusual, so I usually run on 34-36 psi.

Adam[/color:post_uid0]

[Dogo]

[color=#000000:post_uid0]mine are 40psi.

except one which died this morning and so is on 0psi !!

not just a puncture, the side of the tyre had split and ripped apart nicely.[/color:post_uid0]

[Asterix]

[color=#000000:post_uid0]Fair qn... My last car had the classy hubcaps running hardcore 175/65\14's.
Now I have 205/40/17's. The rear tyres are Nankanes (came with a set of these when I bought it). The front were just better than RWC condition so the dealer put a new pair of Sumitomos on the front. Both brands specify different pressures. From memory, the Sumi's say 45-51psi & the others say 40-46psi. WHAT THA??!!
Whadda you guys reckon?[/color:post_uid0]

[MrShadow]

[color=#000000:post_uid0]Run them both at 45-46 psi as this appears to be common to both... ???[/color:post_uid0]

[Critter]

[color=#000000:post_uid0]I was told 40 psi for my 205/40-17s but i use 38psi all round.

The difference in how well the tyres work with 2psi less amazes me......i think you need to experiment a bit, i 've been between 34 and 44 psi, 38 just works.....[/color:post_uid0]

[TURBO MAZDA]

[color=#000000:post_uid0]I have 205/40-ZR17s, I run 38psi in the front and 36psi in the rear.

I have noticed, that the tyre pressure affects the performance of the car, for example, if i run 32 psi in the front tyres i get alot more wheel spin and it doesn't handel as good, so tyre pressure plays a big part in my car.[/color:post_uid0]

[sik astina]

[color=#0000FF:post_uid0]on my 17's i run 38psi. and for long trips etc. canberra, newcaslte i run 40psi


-Mick[/color:post_uid0]

[sirex]

[color=#000000:post_uid0]So, should I be running high 30's or 40psi on my 205/50/16's? Should it be the same all round or higher on the front than the back?[/color:post_uid0]

[Critter]

[color=#000000:post_uid0]I was running 34 all round when I was using 195/50-16s.[/color:post_uid0]

[RedTop]

[color=#000000:post_uid0]Hey Sirex,

I have the same 205/50/16's also and I usually have 34 at the front and 32 on the rear....nothing lower...

RT[/color:post_uid0]

[Rupewrecht]

[color=#000000:post_uid0]i usually run about 36psi in my 205/40/R17s...

Maybe i should be running a bit more. I need to with the added weight (of the intercooler/turbo etc) in the front now.[/color:post_uid0]

[ABC]

[color=#000000:post_uid0]I tend to run about 36 or so on my 16s but like Critter said, just experiment a bit. But I wouldn't go less than about 32-34.

I checked the tyres on my sister's pulsar last time I washed it and one of them was at 14! *:O She says that it runs much better now that they are all at 32. I wonder why? :)[/color:post_uid0]

[sam_seventyseven]

[color=#000000:post_uid1]I've got Yokohamas A539 205/45 R16 and I'm running them at 32 or 36psi depending on where I'm driving. I work in the country so I do a lot of high speed driving so more often than not, they are running around 36psi. Oh yeah, I also filled them with Nitro at Bob Jane (Epping, Vic). It makes a big difference the car and tyres feel compared to normal air. It was $5.50 per wheel with free pressure check and top-ups[/color:post_uid1]

[deon_attard]

[color=#000000:post_uid0]I took a trip up the cost this weekend to Townsville (800km return) and ran 38 in the front, 36 in the back and it didn't feel too bad.

The east coast road is pretty good for the most of it.

In the rough stuff its still harsh as. One of my mates works at a tyre place and wants me to try some "Avon" tyres which he says have a softer side wall hence more give & smoother ride.

I'm still thinking of going back to a 16" wheel, but want to do that without spoiling the looks of the car - if that is possible??

Deon.[/color:post_uid0]

[BigMal]

[color=#000000:post_uid1]I wouldn't run a softer sidewall on an 18" tyre thats asking
for a damaged rim. Maybe change your springs to whiteline
but stay standard height or maybe 1" lower as the front
whitelines are progressive over the standard linear. You
can then have a slightly softer poundage for the first
couple of inches to give a better ride but then harder
once the spring compresses past that.

Regards

Mal[/color:post_uid1]

[BigBoyLemonade]

[color=#006666:post_uid0]I run upto 50psi in mine on trips.. I wear the crap out of the outside on my tyres

Recommended to run 40psi according to the tyre shop... My engineerer told me to run upto 70psi to get it over rego.. (supposely it lifts the car up half an inch) but the tyre says only to run no more than 50psi...

Generally the higher the pressure, the harder the ride but lower pressures in the rain are better for grip[/color:post_uid0]

[mrpayner]

[color=#000000:post_uid0]Crap! With 70psi wouldn't there be a huge risk in blowing out?? That's phenomenal!

Adam[/color:post_uid0]

[deon_attard]

[color=#000000:post_uid0]I'm wondering if there is a way to still make the car look good with smaller rims. I don't think the whiteline springs would make enough difference to make me happy.[/color:post_uid0]

[Toyboy]

[color=#000000:post_uid0]Personally i would keep the 18's on dude,with that kit on any smaller and it doesnt look right ???
I have the same kit,with 17's on and i didnt like it,looks hell better with the 18's :;):[/color:post_uid0]

[deon_attard]

[color=#000000:post_uid0]I love the look which was the inspiration behind the initial purchase.

I'd like to try some different tyres on it and see how that feels.[/color:post_uid0]

[BigBoyLemonade]

[color=#006666:post_uid0]yeah I wouldnt go above the max pressure rating 50psi[/color:post_uid0]

[bRaDiNhO]

[color=#FF0000:post_uid0]Same as turbomazda. 38psi front, 36psi rear. V8 driver Mal Rose told me this at a learn-how-to-slide-your-car day at Oran Park (also known as a defensive driving course :D ) Has worked well since, so never had reason to change.[/color:post_uid0]

[sam_seventyseven]

[color=#000000:post_uid0]I think the guy who said to run tyr epressures at 70psi is a bit silly. The tyre will most likely blow at 70psi. Its just plain dangerous, especially when even the tyre manufacturer says that the max pressure cannot exceed 50psi[/color:post_uid0]

[Trav]

[quote:post_uid0="sam_seventyseven"][color=#000000:post_uid0]I think the guy who said to run tyr epressures at 70psi is a bit silly. The tyre will most likely blow at 70psi. Its just plain dangerous, especially when even the tyre manufacturer says that the max pressure cannot exceed 50psi[/color:post_uid0][/quote:post_uid0]
[color=#3A6EA5:post_uid0]I think what tony was trying to say was that if the car is lowered too far it won't pass a rego inspection, so run them at 70psi to lift the car then put them down again to drive (correct me if i'm wrong here tony)...[/color:post_uid0]

[Dutchy]

I went to a defensive driving course that came with my insurance, it was free so i thought why not :) . The guy there said that small cars should have their tyre pressure on 32psi but medium cars should be 36psi and bigger vehicles like 4WD and stuff should be about 40psi. Now im beginning to wonder if it matters more about the tyres and rims rather than the size or weight of the car, or if that guy didnt know what he was talking about. :?
i always have kept mine on just over 32psi tho.

[Trav]

Welcome Dutchy!!
A friend of mine rund these courses and what you need to realise is that you should run your tyres at the manufacturers specs. Now these specs are everything to do with the tyres and rims. Like most of us on this board we have all changes our rims and therefore will need to alter the tyre pressure according to the tyre manufactures recomendations and also how the car performs.

The guy running your course is used to dealing with idiots that don't know much about cars, so the KISS priciple is used.

[mussing]

I've had my bg since last April, and noticed a slow decline in handling over the 6000kms that I've driven it. I now get a significant amount of understeer in the wet, and fishtailed for the first time ever not two weeks ago (mildly, in the rain, on a hill start).

The last time I re-pressurised my tyres would've been last October or so. They currently read 29psi at the front and 26 at the back, which are the manufacturer's recommendations, but I'm not convinced. I spoke to another bg driver, who said that he always keeps his at 32 (I assume that's the front, not sure about the back).

I'm running on the stock 14" wheels, and relatively new Westlake H660 tyres with plenty of tread. I also drive carefully and always corner in first or second, but the decrease in handling is noticeable. Should I increase the front to 32psi? If so, should I increase the back to about 28-29?

[marcs_sp20]

36psi all round should be the go...

[DavoAust]

Thats pretty low pressure. I used to keep my 14"s at around 34psi. It was 35 at the front and 33 at the back i think. You'll be getting understeer as the tyres will just deform sideways instead of being pushed against the road.

[bourbon]

i suggest 34-35psi on each corner...

30 is even too low...

[hks_kansei]

I run 37-38psi on my 17s

and 35psi front, and 38psi rear on my 15s (but that's for skidpan, to help reduce understeer)

[mussing]

Thanks for the input. I increased each tyre to about 35psi with my dad's air compressor and noticed the better handling straight away.

On that note, how often does everyone check their tyre pressure? And how long can I expect the pressure to stay at that level?

[hks_kansei]

Go buy a tyre gauge (they're only about $20) and check them every week or two.

only check the pressure when the tyres are cold (ie, car has not been driven that day, such as the morning)

[andrewck]

I think a lot has to do with the tyre profile you are using for tyre pressures. Also depends on the level of comfort that you require.

Just my opinion

70 series = 32 to 34 psi

60 series = 34 to 36 psi

50 series = 36 to 38 psi

40 series and below = 38 to 42 psi

BTW those temps are the hot pressures so allow 2 psi less when cold.

These are the pressures I have found to work very well in just about all conditions.

Also tyre pressures should be checked fortnightly

[DavoAust]

ok i had a long talk to the bridgestone mech that changed my tyres over. apparently for handling purposes run 14" at around 36 psi hot, so 34 psi cold.

17" with a 40 profile should be around 41 hot so 39 cold. i've run my nexens higher and lower and you can tell the difference. under that by 2-3psi means smoother ride but more understeer. over it by 2-3psi is a had ride with understeer to quick oversteer coming off the throttle