Anyway... I like mine on 34 psi all round. feels nice and grippy in all conditions. I drive a leon cupra mk1.
I did notice today that mine states 33 for up to 3 people + luggage and something over 40 (can't remember the exact figure) for 5 people + luggage!
I must say, what I have heard agrees with antnee with lowering pressures in the snow for more grip. And with regards to most cars being 28-30psi, I have always thought the difference to be the lower profile tyres needing higher pressure to avoid the alloys touching the ground when driving over potholes etc....
OH NO NOT AGAIN!!!
LOL
Gas compresses, if your tyres were filled with a non compressable liquid, say water, the pressure in the tyres would not adversly effect the way the tyre deformed when hitting potholes.
With gas in there the tyre will deflect more with less pressure.
With a stiff race bred low profile tyre when you reduce the pressure the middle of the tyre comes away from the road and its only the outer edges that are touching the road.
As m0rk has said, over inflation pushes the middle of the tyre into the road and lifts the outer edges.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=2
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=3
Very interesting reading with pretty pictures too, lol
LOL
Gas compresses, if your tyres were filled with a non compressable liquid, say water, the pressure in the tyres would not adversly effect the way the tyre deformed when hitting potholes.
With gas in there the tyre will deflect more with less pressure.
With a stiff race bred low profile tyre when you reduce the pressure the middle of the tyre comes away from the road and its only the outer edges that are touching the road.
As m0rk has said, over inflation pushes the middle of the tyre into the road and lifts the outer edges.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=2
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=3
Very interesting reading with pretty pictures too, lol
yeah so if gas compresses, when a pothole is hit, the gas will compress, meaning less volume of air inside the tyre, and the tyre distorting allowing the alloy closer to the tarmac... obviously if this is done at a faster speed, the rim would stand a chance of making contact with the edge of the pothole and doing some damage... more pressure inside the tyre would reduce the chances of this surely???
Unless I've misunderstood you both, Willie is saying that the centre of the tyre will deform, but not the walls, so the rim should be safe?
even if that was the case, surely its no good for the tyre walls if they are taking all the strain? and that would be why the increased pressure is recommended for low profile tyres?
I thought they were designed to take the increased strain, like the difference between your house walls and roof; they're engineered to do different things but ultimately both (should) keep you warm and dry inside
By the way, as my best mate pointed out last night; I make very odd and seemingly unrelated analogies
By the way, as my best mate pointed out last night; I make very odd and seemingly unrelated analogies
haha no i do the same mate dont worry, i see where you're coming from....
yeah im guessing they will be engineered to take extra strain, but at the same time, a sharp pothole edge pressing against two tyre walls, or pressing against two tyre walls with 22cm of rubber also taking some of the pressure, surely the latter of the two would be the better option!
As reinforced as they may be, I can't see two bits of rubber (tyre walls) taking the strain of 350kg (1/4 of 1400kg) against the edge of a pothole very easily!
edit: and obviously if this were the front, then there would be more than 350kg per tyre!
yeah im guessing they will be engineered to take extra strain, but at the same time, a sharp pothole edge pressing against two tyre walls, or pressing against two tyre walls with 22cm of rubber also taking some of the pressure, surely the latter of the two would be the better option!
As reinforced as they may be, I can't see two bits of rubber (tyre walls) taking the strain of 350kg (1/4 of 1400kg) against the edge of a pothole very easily!
edit: and obviously if this were the front, then there would be more than 350kg per tyre!
ive never changed tyre presure for winter or summer that for car and lorrys, cars get 32psi all round, lorrys get 90 and the rear and 125psi on the front,
The volume of air will not change it will just be at a higher pressure. The volume of tyre will change but will be supported by a higher tyre pressure.
So yes the higher the pressure the less chance you have of bottoming out your alloys and busting tyre and rim.
BUT remember if you are say running at 50PSI and you hit a big pothole hard you do have the chance of raising the internal pressure beyond its limits and bursting the tyre without the rim hitting the tyre.
The rim would not be safer with less pressure as it will still be closer to the rim. It doesn't mean the tyre is further away from the rim it just means the centre of the tyre is slightly pushed intowards the inner rim.
Yes, more pressure = more resistance to alloy bottoming out on the tyre and busting it.
I thought they were designed to take the increased strain, like the difference between your house walls and roof; they're engineered to do different things but ultimately both (should) keep you warm and dry inside
By the way, as my best mate pointed out last night; I make very odd and seemingly unrelated analogies
I believe your mate about your analogies, but it's obviously what makes sense in your head
Yup the LCR is rated for 680-690Kgs for the front so pretty much half the car weight per wheel.
The long and short of it is, the bigger the profile the less chance you have of busting your tyre.
In Canada/North america they get SERIOUS pothole in the back end of winter/early spring. you won't see many guys running less than 50 profile tyres even on performance cars.
Must run 55+ profile.
At worst with large profile tyres you will damage the side wall giving you bubbles with low profile 35-40 tyres you WILL bust your alloy and tyre with a large pothole at speed.
I proved this last week with my brand new winter tyres on my Audi with 235-40-18's to my cost (£200)
![[:@]](/forums/styles/seatcupra/oldforumsmileys/furious.gif "Furious [:@]")
I don't know if we're misunderstanding each other or not, but I meant that what you had posted earlier suggested that the centre of the tread would deform over a bump, and not the edges near the tyre wall. I must admit that "The rim would not be safer with less pressure as it will still be closer to the rim" confused me a little because the rim will be closer to the rim?
OOPS
The centre of the tyre will deform standing still due to the reduced tyre pressure.
Over bumps it will act as a properly inflated tyre but with less air as a cusion to protect from the rim hitting the tyre and busting it.
Take a look at the links I've posted there very clear and well put.
The centre of the tyre will deform standing still due to the reduced tyre pressure.
Over bumps it will act as a properly inflated tyre but with less air as a cusion to protect from the rim hitting the tyre and busting it.
Take a look at the links I've posted there very clear and well put.
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