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different tires front/rear- problem??

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jonph

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Apr 26, 2004, 7:40:42 AM4/26/04
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I have a BMW 330 which needs new rear tires, the fronts are standard
Michelins, I want to eventually have all Pirelli P-Zero Rossos so I want to
put the Pirelli's on the rear now. The BMW dealership tell me that
different tyre brands front and rear can cause problems, particularly for
the automatic transmission. Is this true?

thanks,
Jonathan
jhjph...@ANTISPAM.hotmail.com


Jeremy

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Apr 26, 2004, 7:44:41 AM4/26/04
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In article <c6isfs$qq5$1...@news6.svr.pol.co.uk>, jonph says...

> I have a BMW 330 which needs new rear tires, the fronts are standard
> Michelins, I want to eventually have all Pirelli P-Zero Rossos so I want to
> put the Pirelli's on the rear now. The BMW dealership tell me that
> different tyre brands front and rear can cause problems, particularly for
> the automatic transmission. Is this true?

I could be worng but I don't think that's true for 2wd cars - I have
heard of problems with 4wd though if you don't have matching tyres F&R.

It is not recommended to have different tyre types on the same axle
though.

--
jeremy
['97 BMW 523i SE Touring]

Fred W.

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Apr 26, 2004, 10:05:13 AM4/26/04
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"jonph" <ne...@greenonred.co.uk> wrote in message
news:c6isfs$qq5$1...@news6.svr.pol.co.uk...

> I have a BMW 330 which needs new rear tires, the fronts are standard
> Michelins, I want to eventually have all Pirelli P-Zero Rossos so I want
to
> put the Pirelli's on the rear now. The BMW dealership tell me that
> different tyre brands front and rear can cause problems, particularly for
> the automatic transmission. Is this true?

Not so much for the transmission, but the outside tire circumferences should
be close or you will fool the ABS / TCS into thinking that the smaller
wheels are slipping or the bigger ones are locking up. I would think that if
you replaced with the same size tires you should be OK

-Fred W


jonph

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Apr 26, 2004, 10:35:40 AM4/26/04
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I'm not talking about changing the tire size, just replacing the same size
tires with different brand.


"Fred W." <Fred.Wills@allspam myrealbox.com> wrote in message
news:dsKdnU6ESru...@adelphia.com...

Fred W.

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Apr 26, 2004, 11:11:00 AM4/26/04
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"jonph" <ne...@greenonred.co.uk> wrote in message
news:c6j6o3$bfi$1...@news5.svr.pol.co.uk...

> I'm not talking about changing the tire size, just replacing the same size
> tires with different brand.


Right, and the point which I did not make very well is that tire
circumference for the same "size" varies by brand and also obviously
decreases some as the tires wear.

Try going to www.tirerack.com and look up the specs for circumference of the
original tires and the ones you are considering. Then reduce the
circumference of the old front tires by 3.14 (pi) times twice the amount of
tread wear. This would give you the actual comparison of the circumferences
between the old ones on the front and new ones in the rear.

-Fred W


adder

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Apr 27, 2004, 4:39:05 AM4/27/04
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Just put the new tyres on, drive it & don't worry about it. It can
make the handling a bit odd if you're really pushing the car but not
enough to worry about.
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