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      11-29-2020, 12:13 PM   #45
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Originally Posted by brava09 View Post
So the 56% nose weight for the audis is bad, but the 53% nose weight of the new M3 competition is about the same. Add the awd and there you have the 56%
Not quite sure where you are getting at here...

To recap: 50-50 weight distribution is not ideal, contrary to what BMW wants us to believe. Rear weight bias is preferable for sport driving dynamics. 53% front weight bias for the G8X is certainly not going in the right direction. And yes, the AWD G8X will be even worse with 54-55% of its weight on the front axle. The RS4's 56% is even worse. And in case you wonder, yes those % points are all significant in terms of driving dynamics. That's the whole point of my post.

And I am not an Audi hater, quite the contrary, we've had an S or RS Audi in our driveway for the last decade. My wife has a deposit down for a 2021 RS6. We are actually moving away from BMW as my next purchase will not be an ///M.
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      11-29-2020, 12:46 PM   #46
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The F90 has 54.4% weight on the front axle. As CanAutM3 note the G8X AWD is likely to be very similar to that number. The G8X adding significant front track and rubber to the road vs. the F8X should help counter understeer. To what degree? We’ll have to wait 6-8 months to see.
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      11-29-2020, 01:15 PM   #47
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I don’t know if anyone here is an F1 fan but if any of the new weight is contributing to a safer car, I’ll gladly take it.
The miracle engineering that saved Grosjean’s life today, how is that even possible for a human to survive that?
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      11-29-2020, 01:41 PM   #48
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Originally Posted by solstice View Post
The F90 has 54.4% weight on the front axle. As CanAutM3 note the G8X AWD is likely to be very similar to that number. The G8X adding significant front track and rubber to the road vs. the F8X should help counter understeer. To what degree? We’ll have to wait 6-8 months to see.
We'll have to wait for TireRack tread width measurements to conclude, but based on nominal dimensions, I would not say the G8X has added "significant" rubber to the road. It is typical of the increase in size between generations:

225/255 E46
245/265 E9X
255/275 F8X base
265/285 F8X comp/CS/GTS
275/285 G8X base /comp
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      11-29-2020, 01:45 PM   #49
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Quote:
Originally Posted by CanAutM3 View Post
We'll have to wait for TireRack tread width measurements to conclude, but based on nominal dimensions, I would not say the G8X has added "significant" rubber to the road. It is typical of the increase in size between generations:

225/255 E46
245/265 E9X
255/275 F8X base
265/285 F8X comp/CS/GTS
275/285 G8X base /comp
My car has 255s the only width available at launch so I’m sure it’s significant. The 265s came later. Maybe the G8X will add 285s later for some models...we don’t know.

Also significant and unusual aren’t the same thing, it can be typical and still be significant

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      11-29-2020, 03:22 PM   #50
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Originally Posted by solstice View Post
My car has 255s the only width available at launch so I’m sure it’s significant. The 265s came later. Maybe the G8X will add 285s later for some models...we don’t know.

Also significant and unusual aren’t the same thing, it can be typical and still be significant
I don't consider going one-up is size to be "significant". The 20-21 MP wheels are 285/30R20-295/25R21 though. I think what is more telling is that they have reduced the width stagger, likely to offset the front weight bias.
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      11-29-2020, 04:57 PM   #51
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Originally Posted by CanAutM3 View Post
I don't consider going one-up is size to be "significant". The 20-21 MP wheels are 285/30R20-295/25R21 though. I think what is more telling is that they have reduced the width stagger, likely to offset the front weight bias.
Well we will have to disagree here. I’ve upsized cars front tire width one size a few times and there is a very notable difference. Two or three sizes (MP, maybe CS ) as will be the case with my car is very significant.

What further make me optimistic is that the majority of the preproduction car drivers singled out the front axles better bite when compared to the F82 competition. It is likely the main reason is improved front end tire grip. More front end grip should result in reduced understeer at the same speed. At the edge there could still be more understeer than the F8X but that will be at a higher speed than the F8X is capable of.

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      11-29-2020, 05:29 PM   #52
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Where this discussion of front/rear balance become really interesting is the two opposite measures taken.

- The staggered width is reduced which increases front grip bias.
- Staggered diameter is introduced increasing rear grip bias.

So why are they introducing the staggered diameter on this car which by specifications should have understeer tendencies? That is a nice little mystery
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      12-02-2020, 01:59 PM   #53
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Quote:
Originally Posted by solstice View Post
The superior motors, ergonomics and balance of an RWD chassis as it always has been. Nothing has changed in this equation. Audi has had the one advantage of traction but that is now gone making the Audi even more irrelevant.
I agree. BMW makes a terrific vehicle. Design is the current hangup--IMHO.
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      12-04-2020, 07:10 AM   #54
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Quote:
Originally Posted by solstice View Post
Where this discussion of front/rear balance become really interesting is the two opposite measures taken.

- The staggered width is reduced which increases front grip bias.
- Staggered diameter is introduced increasing rear grip bias.

So why are they introducing the staggered diameter on this car which by specifications should have understeer tendencies? That is a nice little mystery
It's the opposite. The staggered diameter improves front end grip. It's all about increasing front end grip on the G8X, likely to offset the increased front weight bias.
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      12-04-2020, 10:48 AM   #55
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Originally Posted by CanAutM3 View Post
It's the opposite. The staggered diameter improves front end grip. It's all about increasing front end grip on the G8X, likely to offset the increased front weight bias.
Exactly. Wider front tires and the help from the staggered diameter. It’s too early to jump on the negative impact of the shift in weight balance.
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      12-04-2020, 10:52 AM   #56
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Originally Posted by solstice View Post
Exactly. Wider front tires and the help from the staggered diameter. It’s too early to jump on the negative impact of the shift in weight balance.
More weight on the front is bad regardless what measures are done to try to counter the effect. Our RS3, has 255 front and 235 rear from the factory to offset the weight distribution, it helps but it does not alleviate the fact the it is nose heavy. For instance, it destroys its front tires on track in no time.
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      12-04-2020, 11:11 AM   #57
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Originally Posted by CanAutM3 View Post
More weight on the front is bad regardless what measures are done to try to counter the effect. Our RS3, has 255 front and 235 rear from the factory to offset the weight distribution, it helps but it does not alleviate the fact the it is nose heavy. For instance, it destroys its front tires on track in no time.
It’s also Haldex AWD so it’s not really comparable with the RWD or AWD G8X. But more weight, grip, power and higher speeds will undoubtedly increase tire and brake wear all around.

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      12-04-2020, 09:23 PM   #58
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I suspect the rears will be a limiting factor at 285, the front will have tons of grip. It will be an absolute hooligan out of the box I think with those torque levels. It will be fast around a track, in the same way an M8 is fast. Tons of mechanical grip, with big power controlled by a trick differential and clever electronics. Its going to absolutely lunch consumables and the AT gearbox will probably overheat with sticky tires, but no question its going to have serious pace.
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      12-04-2020, 09:28 PM   #59
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Originally Posted by Montaver View Post
I suspect the rears will be a limiting factor at 285, the front will have tons of grip. It will be an absolute hooligan out of the box I think with those torque levels. It will be fast around a track, in the same way an M8 is fast. Tons of mechanical grip, with big power controlled by a trick differential and clever electronics. Its going to absolutely lunch consumables and the AT gearbox will probably overheat with sticky tires, but no question its going to have serious pace.
Agreed, but you would hope the AT has been stress tested by the the G8X with sticky tires since in Europe you can have it with Cup 2 tires from the factory and then you have the M8 and M5 using the same transmission with even more power.
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      12-05-2020, 01:05 PM   #60
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Originally Posted by solstice View Post
Agreed, but you would hope the AT has been stress tested by the the G8X with sticky tires since in Europe you can have it with Cup 2 tires from the factory and then you have the M8 and M5 using the same transmission with even more power.
Not only in Europe. PSC2 are also offered an as option on the G8x in Canada
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      12-21-2020, 09:00 AM   #61
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Originally Posted by CanAutM3 View Post
Quote:
Originally Posted by solstice View Post
And the weight over the front axle is mainly a symptom of the FWD chassis where the engines are mounted more forward and only marginally a symptom of the AWD transfer case weight. I.e. adding AWD to a RWD car like a BMW or Porsche does not make it behave like an Audi. That is a misconception.
I agree, the chosen chassis architecture for Audi makes them very nose heavy. IIRC, the B9 RS4 carries a whopping 56% of its porky weight on the front axle. It is the combination of AWD and nose heaviness that makes them plow.

My point though is that BMW is edging more and more in that direction, heavier AWD cars with more weight on the front axle. This moves them closer to "Audi" handling dynamics and away from traditional BMW ones.
Case in point, excerpt from C&D M440i xDrive review:

It's now basically a two-ton car in the top M440i xDrive trim, with our test car placing a substantial 53.8 percent of that mass on its front wheels. Even with 19-inch Michelin Pilot Sport 4S summer tires (18s with all-seasons are standard), it managed only 0.91 g of skidpad grip, and understeer dominates.

The readout showed 53.8 percent of this car's nearly two-ton mass was positioned over the front axle. This certainly contributed to the M440i's poor 0.91-g skidpad result, the worst we've ever achieved in a Michelin Pilot Sport 4S–shod car.
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      12-22-2020, 11:55 AM   #62
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Quote:
Originally Posted by CanAutM3 View Post
Case in point, excerpt from C&D M440i xDrive review:

It's now basically a two-ton car in the top M440i xDrive trim, with our test car placing a substantial 53.8 percent of that mass on its front wheels. Even with 19-inch Michelin Pilot Sport 4S summer tires (18s with all-seasons are standard), it managed only 0.91 g of skidpad grip, and understeer dominates.

The readout showed 53.8 percent of this car's nearly two-ton mass was positioned over the front axle. This certainly contributed to the M440i's poor 0.91-g skidpad result, the worst we've ever achieved in a Michelin Pilot Sport 4S–shod car.
Good example of that one number isn’t always telling the other.
The F90 pulls a 1g with over 54% weight on the front axle. I expect the G8X to do a bit better than that.
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      12-22-2020, 05:01 PM   #63
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Originally Posted by solstice View Post
Good example of that one number isn’t always telling the other.
The F90 pulls a 1g with over 54% weight on the front axle. I expect the G8X to do a bit better than that.
///M will definitely work its magic on the F8X chassis. But physics is physics and one can only wonder what it could have done with a more favourable weight distribution.
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      12-22-2020, 05:34 PM   #64
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///M will definitely work its magic on the F8X chassis. But physics is physics and one can only wonder what it could have done with a more favourable weight distribution.
I’m sure M have been thinking this since the M1, if only we didn’t have to start with a family car...
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