[RahulNagaraj]

Bentley has unveiled what it claims to be the world's largest carbon-fibre wheels to go into production. The wheels measure 22-inches in diameter and will debut on the Bentayga SUV later this year.



The luxury car brand claims that the wheels comply with Technical Inspection Association (TUV) standards. These are also the first carbon wheels ever produced to pass biaxial stress testing, radial & lateral impact testing, tyre over-pressure and other excessive torque tests.



The carbon wheels have also gone through a range of impact and performance tests, including testing on the Nurburgring Nordschleife, before its final sign off.



Bentley claims that apart from weight savings, the new carbon fibre wheels offer a number of advantages over aluminium rims. These include increased safety, better steering control, improved braking performance due to the reduced unsprung mass and reduced tyre wear.

The pricing for the carbon wheels will be announced later.

Link to Team-BHP news

[abhishek46]

First create a massive lumbering 2.5 tonnage behemoth.

And then offer to save ~20Kgs of weight by applying carbon wheels.

Well done!

[SnS_12]

Just carbon fibre on wheels looks too boring.. If weight reduction is the aim then Titanium and CB work well as demonstrated by HRE

[Kosfactor]

Plastic leather seats, plastic interiors and now Plastic wheels as well. Imagine the premium they would charge for this over good old shiny metal wheels. What a wonderful world we are in

[GTO]

Mod Note: Thread moved to the tyre & wheel section!

[Turbohead]

Considering how stiff carbon fibre is, wouldn't the ride quality go for a toss? I mean the whole point of a Bentley is to go wafting or cruising. After all, most car reviewers mention how you can feel every rumble in a carbon fibre body.

Confused with Bentley's intention

[RedTerrano]

Originally Posted by Turbohead

Considering how stiff carbon fibre is, wouldn't the ride quality go for a toss?

I am no expert but it's obvious that the rims don't deform. Its the tyres and shock absorbers who deform and this results in ride quality.

[QuentinTino]

For all practical purposes, these wheels are a total dud
But,
For all exuberant purposes these wheels look RICH!
I won’t be surprised if I see one of these in the Ambani Garage soon

[kar_thikr]

As impressive as this is, What Koenigsegg made 6 years ago was even more spectacular. They have now pioneered the aircore design, which are the hollow-spoke 20 & 21-inch wheels weighing a maximum of 8 Kg.

These are the hollow-core carbon fibre wheel with 24k white gold rated for 500km/hr and weighs 5.9kg.

There is no specific mention about the weight of the Bentley wheels anywhere in any article.

[thechinmay]

Originally Posted by RahulNagaraj

The carbon wheels have also gone through a range of impact and performance tests, including testing on the Nurburgring Nordschleife, before its final sign off.

The Nurburgring is fine and all, but will they handle the potholes on the Western Express Highway at 80 kmph?

On a serious note, carbon fibre is extremely difficult to repair and is prone to cracking. Hopefully they have overcome these limitations and they manage to open the door for more applications of carbon fibre.

[shree_shell]

Originally Posted by abhishek46

First create a massive lumbering 2.5 tonnage behemoth.

And then offer to save ~20Kgs of weight by applying carbon wheels.

Well done!

One may argue that weight reduction in critical components like unsprung masses may be even more important in luxury SUVs. Even a few lbs make a big difference. That's just physics.

A tire with less weight produces fewer forces within the suspension, leading to composed ride quality. Heavy cars can easily lose composure when the unsprung mass cannot be controlled, even leading to a brief loss of contact with the ground. Looking at the direction all the sports-luxury SUVs are going, with a sportier setup, the unsprung mass may be even more influential than ever while calibrating the ride.

It's a pretty smart move from Bently IMO - working within the constraints of what's physically possible while making sure they stay true to the luxury and comfort brand they are known for. As far as the price of fixing/replacing the carbon fiber wheels is concerned, I don't think the buyers will lose sleep over it.

[v1p3r]

Bentley is merely the customer that is reselling this wheel option through its Mulliner program. The credit for this should go to RIBA Composites, which was founded nearly 35 years ago, and is the major CFRP supplier to Ferrari - all your Ferrari CF trim, the Alfa 4C and 8C chassis, that sort of stuff. This wheel was to be launched 3 years ago, but was delayed in development, since RIBA had major issues with stresses on 5/6/8 spoke wheels.

Bentley is a bit strange when it comes to CFRP stuff. The central trim on the Bentayga console is made of CF, or was in the early cars. They developed a special process to mould it into the specific shape needed - I think it was patented by Prodrive who were the vendors. After all the back and forth, they didn't really save much weight - a few hundred grams maybe - and the CF finish anyway got covered up by veneer, or in some cases just matte black / grey paint. Everyone who saw this play out was suitably amused and disappointed.

That's not to take away from the technical achievement of building this wheel. I would be delighted to see some testing and elemental analysis if it exists. I would suppose TUV reports are public so I just might get lucky.

Originally Posted by RedTerrano

I am no expert but it's obvious that the rims don't deform. Its the tyres and shock absorbers who deform and this results in ride quality.

You are right. A wheel's job is to be as stiff and as light as possible, given the pre-existing condition of cost.

Originally Posted by SnS_12

Just carbon fibre on wheels looks too boring.. If weight reduction is the aim then Titanium and CB work well as demonstrated by HRE

I would be loathe to trust additive manufacturing for high stress applications like SUV wheels. They may survive drag racing and some circuit racing, but I wager they will be far more prone to damage (as a factor of weight) than CF wheels.

Originally Posted by abhishek46

First create a massive lumbering 2.5 tonnage behemoth.

And then offer to save ~20Kgs of weight by applying carbon wheels.

A wheel saving a couple of kilos is felt a lot more than in the cabin. Unsprung weight deltas change steering feel, responsiveness, and suspension characteristics. There is a good human parallel - carry 5 kilos in a backpack and you may not get very tired even after walking a few km. But tie 2 x 2.5 kg weights around your ankles and attempt the same, and you'll know the difference.

Originally Posted by thechinmay

The Nurburgring is fine and all, but will they handle the potholes on the Western Express Highway at 80 kmph?
On a serious note, carbon fibre is extremely difficult to repair and is prone to cracking. Hopefully they have overcome these limitations and they manage to open the door for more applications of carbon fibre.

My guess is that they won't last a pothole shot. The repairing and prone to cracking bits remain the same - it will make no difference to someone who spends 6-7 cr on an SUV. Anyway zero depreciation insurance will cover replacement if you're rich enough to get these in the first place.

Originally Posted by kar_thikr

As impressive as this is, What Koenigsegg made 6 years ago was even more spectacular. They have now pioneered the aircore design, which are the hollow-spoke 20 & 21-inch wheels weighing a maximum of 8 Kg.
Attachment 2185441
These are the hollow-core carbon fibre wheel with 24k white gold rated for 500km/hr and weighs 5.9kg.

There is no specific mention about the weight of the Bentley wheels anywhere in any article.

K'egg (and Pagani) are masters of CF. I daresay that CvK is actually more of a scientist than Horacio, who is more of an artist. The wheel itself is a staggering achievement, though the 'AIRCORE' patent is more marketing than anything else. Hollow spoke wheels have been around for a while previously, K'egg's wheel was the first to have a hollow function in CF.

[SnS_12]

Originally Posted by v1p3r

I would be loathe to trust additive manufacturing for high stress applications like SUV wheels. They may survive drag racing and some circuit racing, but I wager they will be far more prone to damage (as a factor of weight) than CF wheels.

Looking at the cost of CF and Titanium rims, it will only be fitted in SUV's who's owners would like to go from A to B in style and these vehicles won't be subjected to any abuse (hopefully).

For proper SUV's these wheels would be too expensive and just won't solve the purpose for the environment they would be used.

HRE is just trying to show what is possible with additive manufacturing and this particular wheel was printed in 5 different pieces that were fixed to the carbon fiber hub using titanium fasteners. However, they plan to have printers in the future which will be capable of producing the entire rim in one piece.

The biggest benefit of using additive manufacturing for HRE was that only 5% of the original material was lost. In comparison, with traditional production methods, this can go up to 80%. When a wheel is forged, it starts with a big block of 45 kilos metal, usually aluminum. Most of this material is then machined to obtain a light and strong rim. Titanium has more interesting characteristics than aluminum, such as better resistance to corrosion and strength. However, performing the same machining operation from titanium would be extremely expensive. That’s why HRE is experimenting with 3D printing as it can be an interesting alternative.