Koenigsegg Make first hollow carbon fiber wheel
 

The 2013 Agera R features the world's first hollow, one piece, super light carbon fiber wheel, using a proprietary method developed by Koenigsegg named Aircore Technology. The Aircore wheels save close to 20kg in unsprung mass, while providing great integrity and safety. The only metal part in the wheel is the tire valve - the rest is all one piece hollow carbon.

Read more: http://www.worldcarfans.com/11203024...#ixzz1nzCUDIOf

That's pretty interesting, wish there was more info on the wheel.

A company called 360 has been making CF wheels or some time...


http://www.exoticsandluxury.com/wp-c...rged-photo.jpg

yeah but theres is hollow.....

Ah, I see... Sounds unnecessary...

Technological advance is unnecessary? Excessive, yes. Unnecessary? No.

That's what I've been looking for a while (more hollow wheel info) to show my shop and see what they think but I keep getting that same little info then about the car.

Hollow CF is nothing new. Epoxy resin (not polyester resin), polystyrene core. Make part. Dissolve out core with acetone. Done.

All right, but outside of the occasional motorcycle wheel, has there been any other application of hollow CF wheels? The fact that Koenigsegg is confident enough to put these onto a production car says something...that the technology is getting to a usable point while being safe. I bet it's just a matter of cost now.

That's all that it ever has been for years. Koenigsegg is a niche builder with huge margins so the CF wheels isn't really earth-shattering news. Tech is mature but still expensive due to the amount of labour involved, that's all.

Wow. CF being used for all types of interesting ways. I want more info about the wheel though.

I know CF is light & strong and all... but is it strong enough to take the all the beating?

The first? hardly.

The first OEM hollow spoke cfrp wheels, sure. Formula SAE teams have been making them since ~2005.


That all depends on how large of a safety factor the engineers used. But , yes, cfrp wheels can be ridiculously tough/strong if they are designed to be.

Can you teach me some... I'm a newb on those thing.

Dimman, I know you know some info too, so spill it out to teach me ;)

Right? Especially since CF tends to break clean and or shatter instead of cracking. Would be interesting to see what their R&D found happens to the wheel in regular usage and how long these things stay reliable for.

Exactly, how well will these wheels stand up for?

have fun using those on anything but a racetrack. You can't repair CF like aluminum or magnesium. These would be for those with mere money than sense...and show cars (same thing)

A factor of safety is used by engineers to account for material defects and other unforeseen events that would cause a part to fail during operation.

In the case of a wheel, the engineers would have started of with certain design requirements, such as a minimum strength and a minimum fatigue life. The wheel would have to be able to withstand the occasional pothole and last through 100,000+ miles of use. So they'd figure out what sort of loads will be placed on the wheels and how many times it will happen. Either with real world testing or a lab experiment, they'd find out how much force the wheel is subjected to when it hits a pothole of a certain size at a certain speed, and they would design the wheel to not bend/break under that force. But since the engineers can never be perfectly sure that every wheel will be made perfectly (most won't be), or that the impact will be exactly as predicted, they need to add in extra strength to make sure that the wheels won't fail and cause someone to be hurt or killed.

If a 6061-T6 aluminum (yield stress of 40,000 psi) part was being designed with a safety factor of 2, the maximum stress anywhere on the part during the expected loading scenario should not exceed 20,000psi. 20 x 2 = 40.

Safety factors are required in any application, even when weight is crucial. NASA uses safety factors in the range of 1.1-1.05 on satellites and rockets, and that's part of the reason why their stuff costs as much as it does: utterly insane quality control.

If Koenigsegg designed the wheels to be durable, they will be. If they sacrificed durability for weight, they won't be.

1.1-1.05???

Aviation uses a safety factor of 10 minimum building aircraft/parts (hence why whenever fraudulent grade parts are intentionally sold for repairs, consequences can be catastrophic). I would expect NASA to be higher.

^ Curious how much serious composite engineering went into them. Wouldn't they have been better off using unidirectional fibers designed to resist specific loads? I know that's how racing tubs are designed. Also custom 'homemade' carbon bicycle frames.

Of course I guess it could be a purely cosmetic outer layer because shiny 2x2 carbon = sexiness.

Plus is Koenigsegg honestly considered OEM? I though they were really expensive kit cars with Ford power? (ie they made frames, bodies, interiors and maybe suspension links and everything else was off-the-shelf)

Thanks, I kinda got an idea... I still a bit confused, but I got the basic down :happy0180:

We must be using the term differently. To the best of my knowledge 1.5 is standard practice for aviation.

Not as sexy as 12k spread tow cloth.:drool:

I would be flabbergasted if there hasn't been a great deal of time and expertise put into those wheels. I'm sure there are unidirectional fibers somewhere in the layup, but wheels are also subjected to a great deal of shear force as well, for which 45/-45 cloth is ideal.

To the best of my knowledge, they do just about everything in-house or have supplied bespoke. In the past they've sourced engines from Ford, but they have now designed and developed their own. They're a lot closer to Pagani than to Caterham.

I really hate using Wiki for this sort of stuff.

http://en.wikipedia.org/wiki/Safety_factor

I read of safety factor when I was studying lifting equipment (particularly ropes, slings, chains, etc). I remember 10 off the top of my head and 5 for things like elevators and cranes.

Apparently wiki at the bottom [Choosing Design Factors] has it quoted as 1.2-3.0 depending on materials and structural part. Looking at FAA it seems like those are the tolerances, depending on the part or structure. Perhaps what I learned was bunk, and used for easy examples... who knows. Carry on!

Did a bit of looking, and the new Agera is a whole lot improved over the original CCR (what I think of when I think Koenigsegg).

Looks like they invested their over-priced kit-car profits wisely.

What were the problems with the old Dymag (CF rim magnesium center) wheels? Something about de-lamination or breaking from braking heat?

How would a whole carbon wheel affect brake temperature in this case since there is less of a heat-sink to suck heat away from the hub?

I thought the issue with those was fatigue failure in the magnesium spokes, or maybe a failure in the adhesive between the magnesium and carbon. I don't recall anything about delamination, though I may be mistaken.

The hub would probably run a bit hotter, but most of the brake cooling comes from airflow through the rotor. It was an issue with the very first CFRP wheels which were, I believe, made by Lancia for WRC back in the 80's. They were pretty much solid disks with very little in the way of ventilation.

These look so good, I think I may make my own damn carbon fiber wheels!








Only with an aluminum core.













Sourced from Rota...

Perhaps excessive is a better word then...

the 360 wheels look wayyyy better.

Also, CF wheels are old news, at least in the Motorcycle world. But hollow, that's pretty cool.

Only concern is, CF is known to be very strong, but when it reaches it's failure point...it's known to be catastrophic

Yeah but these go to 11