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7 Series - F01 / F02 (2009 - current)
The new re-designed 7 series F01 / F02 leads off the BMW Fxx chassis code!

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  #1  
Old 04-29-2012, 09:17 PM
chrischeung chrischeung is offline
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Why are the 20" tires on the ActiveHybrid different profiles?

I was wondering if anyone knew why the optional 20" tires on the ActiveHybrid 7 are lower profiles compared to the regular 750i tires. On the regular 750i. the 20" option (and individual 20s) are 245/45 front, 275/40 rear. Yet on the ActiveHybrid, the tires are 245/40 and 275/35 respectively, same width, lower profiled. All wheels are 20x8.5" and 20x10" front to rear.

In my experience, the same sized wheels for the same BMW have the same tires. Why the difference in this case? And if the reason was the ActiveHybrid was heavier so needed more sidewall/air, then the tires should be switched, with the AH running 45 and 40 profiles front to rear, instead of 40 to 35.

Can anyone give any insight?
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2012 ActiveHybrid 750i ED

3/12 ED 7 - thread ID 610350
1/11 ED 6 - thread ID 5767556&postcount=175
4/10 ED 5 - thread ID 453501
5/08 ED 4 - thread ID 290679
3/07 ED 3 - thread ID 201013
3/06 ED 2 - thread ID 136454

Last edited by chrischeung; 04-29-2012 at 10:16 PM.
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  #2  
Old 04-30-2012, 06:04 AM
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hd750Li hd750Li is offline
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I noticed that too when I first saw a 750AH. I asked my SA that same question....His answer was "in theory, the AH has 40 HP more than the traditional 750, and that's why the AH needs 'performance' tires made of a softer type of rubber that gives more grip. The downside is they wear out more quickly. The tradeoff is somewhat stiffer handling, which means better control, but a bumpier ride."
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Old 04-30-2012, 06:08 AM
Glen E Glen E is offline
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"they have less rolling ressitance for higher mileage" - per the training materials on the active cars...
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Old 04-30-2012, 08:42 AM
chrischeung chrischeung is offline
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Quote:
Originally Posted by Glen E View Post
"they have less rolling ressitance for higher mileage" - per the training materials on the active cars...
I think that was the case with the 2011 intial launch versions. But for 2012 they seem to be using the regular 750i tires, and definitely for the 20" option wheels, they are performance rubber.
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2012 ActiveHybrid 750i ED

3/12 ED 7 - thread ID 610350
1/11 ED 6 - thread ID 5767556&postcount=175
4/10 ED 5 - thread ID 453501
5/08 ED 4 - thread ID 290679
3/07 ED 3 - thread ID 201013
3/06 ED 2 - thread ID 136454
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  #5  
Old 04-30-2012, 08:45 AM
chrischeung chrischeung is offline
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Mein Auto: 2012 ActiveHybrid 7 SWB
Quote:
Originally Posted by hd750Li View Post
I noticed that too when I first saw a 750AH. I asked my SA that same question....His answer was "in theory, the AH has 40 HP more than the traditional 750, and that's why the AH needs 'performance' tires made of a softer type of rubber that gives more grip. The downside is they wear out more quickly. The tradeoff is somewhat stiffer handling, which means better control, but a bumpier ride."
Well, the 20" tires and wheels were offered on launch for the 7 series (in Europe), before the AH was released. Plus now looking at all the 7 series 20" upgrade wheels/tires, they all have the lower profile setup. You can see that here - http://www.alloywheelsdirect.net/bmw...ies_f01_alloys

So it's the newer options on the Individual and M-sport tires that are going higher in profile. Perhaps feedback was that the ride for the 7's was generally too choppy for a luxury ride?
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2012 ActiveHybrid 750i ED

3/12 ED 7 - thread ID 610350
1/11 ED 6 - thread ID 5767556&postcount=175
4/10 ED 5 - thread ID 453501
5/08 ED 4 - thread ID 290679
3/07 ED 3 - thread ID 201013
3/06 ED 2 - thread ID 136454

Last edited by chrischeung; 04-30-2012 at 08:46 AM.
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