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Registered 2005 SLK350
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Discussion Starter #1
How lucky can I get? I recently bought a new 2012 Acura TSX on sale as future replacement for my daily driver 2003 Accord. Tonight a friend dropped off her 2011 BMW 328XI as she is leaving the country for a year or more so wants someone to look after/drive/store it. So I have at least a year to compare a few nice driveable cars.

First thing I did was go through the 328 manual and was surprised that while BMW recommended 91 AKI fuel they also state that 89 is OK and will not harm the engine. I wish MB agreed.

Second thing is trying the voice recognition for Nav, Radio, Contacts etc for about 2 hours since I buy cars without Nav and wow does it suck. Google Maps on my HTC Android is so much better. Voice recognition still has a long way to go. Why does a $300 phone have better tech than a $50k car?

Third: apparently the BMW has completely free maintenance including consumables (oil/wipers/etc) for the next 3 years so thats a good consideration.

Fourth: she was told when she bought the car that it had "Nitrogen tires" that needed to be replaced with Nitrogen at BMW. She wasn't sure whether they meant the nitogen or the tires but left me some money in case it needed "special" tires. Hmmmm lets see now ... what do I have that has 18" rims.

Gordon
 

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Premium Member
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2,117 Posts
nitrogen usually means nitrogen filled-it expands less as the tires warm, and tends to leak out less as its a larger molecule...
 

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Sadly Woolly has passed away
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17,375 Posts
nitrogen usually means nitrogen filled-it expands less as the tires warm, and tends to leak out less as its a larger molecule...
. . . and air is 78% Nitrogen . . .rubbing your tyres weekly with snake-oil is far better, as this keeps your tyres nice & supple and improves your ride :)
 

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Registered 2005 SLK350
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158 Posts
Gummi pflege works better than snake oil...

Seriously, nitrogen is better for your tires for several reasons, whether you would notice or not is a different question.
yes air is 78% nitrogen but it is also 21% oxygen. Oxygen will oxidize the rubber over time. At 30 psi this oxidation happens three times faster inside the tire than outside at atmospheric pressure. Many of us drive enough that bi or tri annual tire changes negate this oxidation, but over 4 + years it could degrade the rubber from the inside.
also water vapor is much more soluable in oxygen than nitrogen so there is a greater possibilility for moisture to condense with an air fill than nitrogen.
finally (and now the really esoteric) the thermal coefficients of expansion are slightly different between O2 and N2 so in theory straight N2 will expand at a more consistent rate than a mixed gas like air.
Then again there are those of us who index our plugs, shave webbing down on plastic intake tract, use synthetic brake fluid, etc... its all about what makes you feel good about your ride.
 
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