Help with tyre pressures

Quote:

---

Originally Posted by doogz__

Apparently run flat tyres, depending on size and make, carry a 15-27% weight penalty over non run-flat tyres.

That's a lot of unsprung weight!

---

Thank goodness you don't need to carry a spare :rolleyes: !

True, but a spare wheel would be sprung weight.

Unsprung weight is bad news. That's why race cars, and some road cars (E-type for example) had inboard brakes, to reduce unsprung mass.

Run-flats have a higher rotational inertia as well, adversely affecting braking and acceleration.

Can you tell i really don't like them? lol

Quote:

---

Originally Posted by doogz__

True, but a spare wheel would be sprung weight.

Unsprung weight is bad news. That's why race cars, and some road cars (E-type for example) had inboard brakes, to reduce unsprung mass.

Run-flats have a higher rotational inertia as well, adversely affecting braking and acceleration.

Can you tell i really don't like them? lol

---

Yeah, that was beginning to come across...............doesn't make you a bad person though :lol:

Quote:

---

Originally Posted by 0004BES

The pump at Tesco is set up for 28psi as standard.

---

you do know the arrow buttons will adjust this figure yeah? :p

Quote:

---

Originally Posted by GCA3N

Interesting Ryan, I never run that low think I will try that when I get back see what the difference is. I'm sure I have mentioned this before, but when I first got my new mini I checked the tyre pressures and they were 48-49 psi all round:eek: don't know to this date what that was all about.

---

thats normally delivery pressure, in theory the car can sit around in an airfeild for months without the tyre deformingsounds like it wasn't PDI'd properly :frown:

Bought a Michalin twin foot pump a few years back, I hate those petrol Garage ones. Got my RF 195/55/R16 87H set to 2.2 Bar or 32 Psi as the sticker in the door suggests.

Went into 3 different Tyre places today (long story short two of them would not do a puncture repair on a run flat) Anyway I asked them what they suggested I should run the tryes at pressure wise.

They gave me a print out and according to their computers, the 205/45/17 runflats (one, cooper and S) should be 36psi (front and back), and 39psi loaded. The JCW Cooper S can't remember the tyre is 39psi and 41 loaded. This is all very strange.

I should have said the figures I quoted were for the R50/53:blush: The R56 must be different:Whistle:

Quote:

---

Originally Posted by Big Gordy

I should have said the figures I quoted were for the R50/53:blush: The R56 must be different:Whistle:

---

Ah that's the reason for the discrepency.