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ThoreauHD
05-12-2006, 09:19 PM
Hi,

I have 15 inch Bridgestone Potenza G 009 i believe. The maximum psi is listed at 44. What is the recommended pressure for decent mpg while still being safe. I read that 35-36 may be about right but a bit noisy, but I'm wondering what E34 owners do typically. Thank you.

Zeuk in Oz
05-12-2006, 09:22 PM
Hi,

I have 15 inch Bridgestone Potenza G 009 i believe. The maximum psi is listed at 44. What is the recommended pressure for decent mpg while still being safe. I read that 35-36 may be about right but a bit noisy, but I'm wondering what E34 owners do typically. Thank you.
I run 36-38 for normal use and at least 40 on a trip.

ThoreauHD
05-12-2006, 09:33 PM
OK, thanks.

Adnan
05-12-2006, 10:06 PM
Hi,

I have typically adhered to the settings on the door panel tag: 30 front, 35 rear. The car seems very happy at that setting.

The tires are Yoko AVSdb S2 in the stock 225/60-15 size.

Regards,
Adnan

KenB
05-12-2006, 10:57 PM
I have the same Bridgestones, run 32 front and 33 rear. I started with the door jamb numbers and made these adjustments. With a V8, you might want more up front with the extra weight. Try a couple of different pressures within the tires' and BMW's recommended range and see what you like.

ThoreauHD
05-12-2006, 11:09 PM
Yea, the front is a bit mushed and was looking at adjusting it properly.

Russell
05-13-2006, 07:23 AM
Questions:
Do you rotate tires?
What is the wear pattern? I would suspect the middle
How is your ride? Rough or compliant?
We are talking about stock 15 inch tires?

IMO, your tire pressures just seem rather extreme unless you carry 4 people and a trunk full of stuff at all times.

Zeuk in Oz
05-14-2006, 05:38 PM
Questions:
Do you rotate tires?
What is the wear pattern? I would suspect the middle
How is your ride? Rough or compliant?
We are talking about stock 15 inch tires?

IMO, your tire pressures just seem rather extreme unless you carry 4 people and a trunk full of stuff at all times.
Yes, I rotate front to rear / rear to front on same side half way through tyre life.

Yes my wear pattern is slightly more in the middle than the sides but that is quite deliberate. Usually the car carries one or 2 people.

When a tyre is stressed, as in braking or cornering, it apparently has a habit of sucking in the middle. Thus running "normal or recommended" tyre pressures will give even wear but during cornering or braking you do not have all of the tyre on the road - only the sides.

By running higher tyre pressures, and therefore wearing out the middle more than the sides, when stressed the tyre once again sucks in the middle leaving you with the whole tyre flat on the road when cornering or braking, which in my opinion is the objective. You want as much of the tyre flat on the road during cornering and braking.

These higher tyre pressures also make handling much more precise which I presumes makes sense if my presumptions about tyre behaviour under stress are correct.

My ride is really soft and smooth but this is probably helped by running standard 15" wheels and also Michelin tyres which have a fairly soft side-wall.

I found that my ride improved dramatically when I replaced my worn thrust arms and bushings.

ThoreauHD
05-14-2006, 08:14 PM
The wear pattern... Everything I have on the car is new OEM(15 inch stock). I'm preserving it for posterity. Plain jane perfect and OEM. The tires have 500 miles on them. They are new and have been aligned by the dealer and also a bmw independent service center.

Taking all the advice together, I averaged the mean and set the front to 35.5 and the rear to 36.5. I have a digital PSI reader, so that's how I get the .5. It seems to ride better now, but it could all be in my head. The fronts don't look mushed into the pavement, which is quite helpful when taking turns at 60 mph. Not that I would do that, but if I did.. it would be helpful. Thanks for the advice guys. I can't find **** for tech specs on these tires. You're a lifesaver.

Russell
05-14-2006, 08:23 PM
Thanks. I just replaced my stut arms and bushings and the ride really improved. The front struts were replaced last year. I had lowered the front pressure to 29 psi to hopefully make it ride a bit better.

I think I will begin experimenting with higher tire pressures with digital gauge. I still need to replace my rear struts as they are original. You have been most helpful.

632 Regal
05-14-2006, 10:12 PM
I do 33 front 38 rear, used to run 30/34 but the sides of the front tires were starting to wear a bit.