Staggered 19" front 20" rear with 255mm and 285mm Pilot Sport 4S

[Nictrix]

I would guess you've reduced your acceleration by raising the gearing of your car, those big wheels look to have a greater rolling radius than standard wheels. Tell us what profiles you're running?
Rob

Actually, no as my wheels and tires weigh significantly less than the OEM set up. Less power is required to rotate a lower mass, or put another way, it is easier to rotate a lower mass than a heavier mass. My wheels and tires reduce rotating weight by 22 pounds compared to stock wheels and tires and as such are easier to rotate. Also, with a properly tuned N54 motor, which makes 400 hp or more, the issue is further reduced as a concern.

So what profile rear tyres are you using, as your reasoning only takes into account half of the relevant data?
Rob

Does the fact that the wheels are a lot lighter and easier to rotate not mean that they will spin easier under power?

 

[Valor1]

One HUGE disadvantage you have stated "less weight per cubic centimetre riding on the larger tires" With more rubber on the road their is as you correctly state less pressure on the tyre'. As a result you have poorer grip especially in wet or damp conditions where the tyres dynamics rely on the weight of the vehicle to push it down through the water film and contact the road.
When tyres/wheels are selected by a manufacturer they are done by very skilled engineers, tyre specialists, and computers. They also use feedback from their race teams.
So, they probably know best, best left alone, safety before aesthetics.......

Oh, and make sure you tell your insurer as you have modified the cars handling......

I don't think any race team feeds back information regarding optimal tyre size for a road car, two completely different applications.

Cars often have multiple tyre setups depending on spec. The 3 series for example has optional staggered wheels which come with the M Sport kit. The efficient dynamics cars come with smaller sizes again to reduce fuel consumption.

The tyres are the Z4 aren't selected solely for performance, they also take fuel consumption and road noise into consideration. Putting wider tyres on the Z4 will improve traction but will also increase fuel use and road noise into the cabin.

I can guarantee you that race teams feedback into road car development, why do you think they race to win? It showcases the manufacturers technologies and abilities, M series cars are very race orientated.
Yes cars often have staggered setups AS DESIGNED AND TESTED BY PROFESSIONALS.
All tyres are selected SOLELY for performance, you seem to think that it is only grip that is relative to tyre performance, it includes noise - economy - comfort - grip - braking wet/dry - cornering - acceleration.
Have a read of this website giving the views of professionals in the matter https://www.driving.co.uk/car-clinic/what-you-need-to-know-before-changing-the-size-of-the-wheels-and-tyres-on-your-car/

Sorry, this is just too silly to waste time on. I know engineers who work at mainstream manufacturers and who work for exotic car manufacturers. This will come as a great surprise to you: Bean counters at major manufacturers are not putting the best possible gear in your car. Do you see a carbon fiber driveshaft? Carbon ceramic brakes? Forged or carbon fiber wheels? A carbon fiber tub? Heck, the Z4 has uber cheap brakes in it and just about the worst possible tires with the RFT and you want to tell me this car can't benefit from a forged wheels and maximum performance tires? Wow. Okay. Check please!

 

[Valor1]

Actually, no as my wheels and tires weigh significantly less than the OEM set up. Less power is required to rotate a lower mass, or put another way, it is easier to rotate a lower mass than a heavier mass. My wheels and tires reduce rotating weight by 22 pounds compared to stock wheels and tires and as such are easier to rotate. Also, with a properly tuned N54 motor, which makes 400 hp or more, the issue is further reduced as a concern.

So what profile rear tyres are you using, as your reasoning only takes into account half of the relevant data?
Rob

Does the fact that the wheels are a lot lighter and easier to rotate not mean that they will spin easier under power?

Well, let's just say the Pagani BC and Koenigsegg I saw this weekend....and Jay Leno's Ford GT I saw a couple of weeks ago, all have carbon fiber wheels. Koenigsegg states their carbon wheels save nearly 20kg of weight. (My forged wheels are saving about 10Kg). I'll let folks here do the math and exercise common sense.

 

[Valor1]

So what profile rear tyres are you using, as your reasoning only takes into account half of the relevant data?
Rob

Does the fact that the wheels are a lot lighter and easier to rotate not mean that they will spin easier under power?

Well, let's just say the Pagani BC and Koenigsegg I saw this weekend....and Jay Leno's Ford GT I saw a couple of weeks ago, all have carbon fiber wheels. Koenigsegg states their carbon wheels save nearly 20kg of weight. (My forged wheels are saving about 10Kg). Less mass is easier to "spin" while larger tires with better traction will grip better. So yes, they will spin faster while these tires will have much more grip.

 

[Smartbear]

Actually, no as my wheels and tires weigh significantly less than the OEM set up. Less power is required to rotate a lower mass, or put another way, it is easier to rotate a lower mass than a heavier mass. My wheels and tires reduce rotating weight by 22 pounds compared to stock wheels and tires and as such are easier to rotate. Also, with a properly tuned N54 motor, which makes 400 hp or more, the issue is further reduced as a concern.

So what profile rear tyres are you using, as your reasoning only takes into account half of the relevant data?
Rob

Does the fact that the wheels are a lot lighter and easier to rotate not mean that they will spin easier under power?

If nothing else was changed I would agree, however the op hasn't revealed which tyre profile he's using on the rear & I suspect his tyre choice has raised the car's gearing which would have the effect of reducing the car's acceleration, or at least negating some of the gains that would have been made switching to lighter wheels & retaining the car's original gearing....
Rob

 

[Nictrix]

So what profile rear tyres are you using, as your reasoning only takes into account half of the relevant data?
Rob

Does the fact that the wheels are a lot lighter and easier to rotate not mean that they will spin easier under power?

Well, let's just say the Pagani BC and Koenigsegg I saw this weekend....and Jay Leno's Ford GT I saw a couple of weeks ago, all have carbon fiber wheels. Koenigsegg states their carbon wheels save nearly 20kg of weight. (My forged wheels are saving about 10Kg). I'll let folks here do the math and exercise common sense.

Big difference between all those cars and a Z, all of those have the weight of the engine over the rear wheels keeping it down.

 

[sunnydays]

I don't think any race team feeds back information regarding optimal tyre size for a road car, two completely different applications.

Cars often have multiple tyre setups depending on spec. The 3 series for example has optional staggered wheels which come with the M Sport kit. The efficient dynamics cars come with smaller sizes again to reduce fuel consumption.

The tyres are the Z4 aren't selected solely for performance, they also take fuel consumption and road noise into consideration. Putting wider tyres on the Z4 will improve traction but will also increase fuel use and road noise into the cabin.

I can guarantee you that race teams feedback into road car development, why do you think they race to win? It showcases the manufacturers technologies and abilities, M series cars are very race orientated.
Yes cars often have staggered setups AS DESIGNED AND TESTED BY PROFESSIONALS.
All tyres are selected SOLELY for performance, you seem to think that it is only grip that is relative to tyre performance, it includes noise - economy - comfort - grip - braking wet/dry - cornering - acceleration.
Have a read of this website giving the views of professionals in the matter https://www.driving.co.uk/car-clinic/what-you-need-to-know-before-changing-the-size-of-the-wheels-and-tyres-on-your-car/

Sorry, this is just too silly to waste time on. I know engineers who work at mainstream manufacturers and who work for exotic car manufacturers. This will come as a great surprise to you: Bean counters at major manufacturers are not putting the best possible gear in your car. Do you see a carbon fiber driveshaft? Carbon ceramic brakes? Forged or carbon fiber wheels? A carbon fiber tub? Heck, the Z4 has uber cheap brakes in it and just about the worst possible tires with the RFT and you want to tell me this car can't benefit from a forged wheels and maximum performance tires? Wow. Okay. Check please!

Agree to an extent but remember every car has its market. The reason this car has rfts is so it didnt destroy the last gen Z4M in reviews. The E89 is a GT cruiser not a track car or a super car.

Remember these cars are designed from the ground up, with certain compromises in mind. Cars like the Huayra and Zonda are no compromise all performance cars that are developed and built to take advantage of every last aspect of the car such as the wider tyres and contact patch playing through the suspension.

While lighter alloys and wider tyres should be better, if the car can not take advantage of these due to its inherant design then it acheives nothing.

 

[Valor1]

A few more pics of 19" front 20" rear.

 

[Ducklakeview]

Wow OP that is a nice colour combination. Is that melbourne red and a beige interior? Manual too? Must not be many of those around in 35i form

Don't start that again, please

Nice wheels BTW OP..

Mike

 

[MrPT]

What tyre profiles?

+1

Rear looks lower profile than the front. I guess with staggered diameter wheels you lose the ability to have a fatter rear for comfort (as per recent Porsches) and still keep things ok, visually.

They look pretty good though, OP. Your weather helps.

 

[Valor1]

Wow OP that is a nice colour combination. Is that melbourne red and a beige interior? Manual too? Must not be many of those around in 35i form

Don't start that again, please

Nice wheels BTW OP..

Mike

Thank you Mike

 

[Valor1]

What tyre profiles?

+1

Rear looks lower profile than the front. I guess with staggered diameter wheels you lose the ability to have a fatter rear for comfort (as per recent Porsches) and still keep things ok, visually.

They look pretty good though, OP. Your weather helps.

Off the top of my head I don't remember. I can tell you the car now rides infinitely better than the OEM Bridgestone runflats. When my car was delivered I was so disappointed by the ride quality and creaking noises that I was going to sell the car. But when i replaced the tires to the larger tires the ride quality improvement was night and day.