Tyre Pressure Question

[JB0]

Since purchasing my vehicle, I only checked tyre pressure today. I kept the front threw at 40 psi and the back ones at 36. I know on the door sticker, it said front 35 and rear 32. However, I am going on a motorway journey with 2 passengers and some luggage to boot. This is why my friend recommended the 40/36 pressure.

Will this be fine?

[tobiasdog]

Hi there, what size of tyre do you have?

Regards

Allan

[FROSTYBALLS]

The door sticker should show the tyre pressures for various loads (ie up to 2 people, 2 people plus luggage, etc) - 35 front/32 rear sounds like the normal loading for up to two people in a diesel Auris. For example in my 1.33's the 'normal' tyre pressure is 32psi front and rear.

I would re-check the sticker and go for whichever seems to be the appropriate load/tyre pressure.

[UK Republic]

My SR is on Dunlop 225/45/17 and regardless of occupants and luggage the tyre pressures are 32 psi front and rear for speeds below 99 mph, above that the pressure is 36 psi, that is what is on the sticker and in the handbook.

I have to ask the question, Is your friend more knowledgeable in these matters than Toyota? I think not, so I would go with whatever the designers and builders of your car recommend.

regards Republic UK.

[JB0]

It's a standard size tyre.

He asked me if I was going to drive over 100 mph, and I said I average about 100 mph or 110 mph on the journey. It's a 2 litre d4d tr

[FROSTYBALLS]

Looking at the owners manual, for the 1AD-FTV engine (2.0 D4D) the recommended cold tyre pressures for a car with 4 or 5 people and fully loaded, tyre sizes 195/65R15 & 205/55R16:

1. more than 99mph 40psi front, 36psi rear

2. less than 99mph 35psi front. 32psi rear

So go with the 40psi and 36.

[JB0]

Thanks Frosty. I think the previous owner had it set at this and this is what I've been driving at locally as well.

[FROSTYBALLS]

So when you're driving locally, I'd drop the cold tyre pressures to the 35psi and 32, as having the tyres at 40/36 all the time could affect the handling.

See responses in: http://www.toyotaownersclub.com/forums/topic/149556-tyres-look-deflated-on-toyota-diesel-cars/

[JB0]

Yes, I think I will do when I'm back from my journey.

[UK Republic]

He should have asked you if you were crackers, if you keep me informed as to where you are driving I will make sure I am at least 100 miles away from you.

[FROSTYBALLS]

I'm certainly not condoning speeding in any way, shape or form. One has to be very aware of the very serious risks/consequences involved, not just to oneself but to others, and also, if caught at travelling over 100mph, of the fact one will certainly lose one's licence.

[Cyker]

I routinely used to run 40/35 on my previous Yaris, but currently run 38/33 on this one as it has different tyres.

Such a small increase isn't dangerous and doesn't affect handling noticeably - Maybe slightly more understeer on loose surfaces but more positive feel on twisty A-roads. It's important to drop them back to spec in the snow and ice but even under torrential rain I found the higher pressures were okay (If anything the tyres felt less prone to straight-line aquaplaning!)

A nice bonus is you get slightly better fuel economy!

The main downside is you get more road noise and the ride is noticeably harsher; May increase chances of suspension damage on very bad roads, but then again if your tyres are stupidly low profile, may also reduce the chances of rim damage on such roads!

For high-speed driving, higher is deffo better than lower tho'; The harder the tyre, the less it flexes and the less it flexes, the less chance there is for fatal heat-buildup which could cause the tyre materials to fail and burst - Too-low tyre pressures are much more dangerous than too-high!

[Uncle Buck]

When I read the '100 mph - 110 mph' bit, I actually thought the OP was joking. But if not, perhaps he's talking about travelling in a different country ? It is perfectly legal to drive at those speeds on a derestricted part of the German autobahn for example. My old Alfa used to sit at a steady 130 mph quite happily for over an hour on the way to the Nurburgring.