Tyre Pressure

paulgs1000 said:
Sasker - what year and model is your E85?

Different models and ages came with different size wheels and it would be helpful to know what it came with as standard.

:driving: :thumbsup:
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It's a 2003 z4 3.0i
 
Upload some close up pics of the front & rear wheel+tyre
245 is suggested max for 8j rim but 255 will go on & more than likely not look crazily out of place although the sidewall may look "balloony"
 
mr wilks said:
Upload some close up pics of the front & rear wheel+tyre
245 is suggested max for 8j rim but 255 will go on & more than likely not look crazily out of place although the sidewall may look "balloony"
Click to expand...

I sent you an email earlier with a load of pics attached. May be hard to see though on those ones

I also explained too that I prefer to wait to see if you get any of those wheels in all silver too. Don't think the black will go with my colour after doing a bit of a photo edit earlier on after we spoke
 
Your low aspect ratio tyres ( low hight /width division) need higher pressure , because the maximum load of such a tyre is given to high by the tyre makers.
So before the pressure is calculated out of the load on tyre and for the speed you drive , wich I can do for you with use of an even saver formula then the European tyre makers use , and I once got hold of and went running with, substract about 20% of the given maximum load ( is the same as lowering the loadindex by 8 ).

If you give here the needed data of car and tyres , I wil calculate a lowest pressure wich is save for the tyres.
From tyres: maximum load or loadindex of tyres and speedcode ( S to Y ) and the kind of tyre to determine the pressure needed for the maximum load, wich is not the maximum pressure of the tyre , only given on standard load and XL/reinforced/Extraload tyres.

From car the empty weight and motor in front of back, and the way you load it normally ( persons and their weight :cry: and lugage).
And also the Maximum permissable axle and vehicle weights ( MP A/V W) and the speed you sertainly wont go over and/or maximum technical speed of car.

I expect the outcome higher then you give but still front higher then rear , because load on front higher then rear mostly.
For fully loaded its the other way around mostly because MPAW is mostly rear higher then front.
Nowadays the car makers only give for normal use the pressure needed for the MPAW up to maximum technical car speed, and is says to be for 4 persons and load.
Before 2000 normal use pressure advice was for axle loads determined by the car maker for 3 persons and a little load.
And what now is normal use was before 2000 for fully loaded.
 
I have the correct size front wheels on I have just been told by my mechanic. About 2 inches smaller than the rear wheels so that's saved me some money.

Just need to get 2 x 225/40/18 tyres on and I'm all sorted. :D

God knows why someone decided to put 255 tyres on the front.

Steering and handling should be much improved once I get this done :driving:
 
2 inches :o hope thats a typo Ian :D 8j fronts & 8.5j rear is what you should have so approx 12mm difference in widths between them :thumbsup:
 
he just said about 2 inches but at least I know I have the right wheels now anyway.

Just ordered 2 part worn tyres so hopefully all sorted by Saturday afternoon
 
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