What Wheel?

[raventare]

Mr. Lill, do you know what method of casting they use at Kosei? I have to claim ignorance in their company/products but you have placed them high on my radar.

[JimLill]

I think the problem arises when the "sticky" tire and light weight wheel meet an immovable object...a curb. Luckily they are only on the streets...don't curb your racing

I have witnessed lightweight wheel failure on a 4000 lb car being tracked, no curbs involved.

[raventare]

I know that anything can fail for any number of reasons, especially mfg defect. Magnesium wheels were the most prone to catastrophic failure due to micro cracking due to mis-handling prior to use. Then there are always people that don't read mfg recommendations for loading and use an 8-900 lb max load wheel for a 1000 lb + situation. They drive on the street for a while and think they are ready for "racing". Obviously the stress on a track is greater than you will find on the street and "viola" we have an incident. I guess you could just not drive to guaranty your safety...NOT! I am also guessing the "incident" you mentioned was a track day street car...can't think of a 4000 lb race car.

[JimLill]

Mr. Lill, do you know what method of casting they use at Kosei? I have to claim ignorance in their company/products but you have placed them high on my radar.

Sorry, I overlooked this......... see: http://www.koseijp.co.jp/engfl/NewPa...ogy/K-Spec.htm

[JimLill]

I am also guessing the "incident" you mentioned was a track day street car...can't think of a 4000 lb race car.

The Track = Watkins Glen Int'l
The Car = Volvo S60R (2 up)
The Speed and Turn = 100+ mph into T1

[scotto]

Sorry, I overlooked this......... see: http://www.koseijp.co.jp/engfl/NewPa...ogy/K-Spec.htm

Good discussion! I remember when Kosei was first being offered at Tire Rack. They had an article that explained their special casting process - which enables them to build a lighter yet 'strong' wheel.

Here's another link to more info on that process:

http://www.koseijp.co.jp/engfl/NewPa...rFormingP2.htm

The graphs are interesting showing strength across the wheel, pictures of the grain structure in the metal, and diagrams of the flow forming process. The one graph is perhaps telling showing how in 'conventional casting' that the inner rim has less tensile strength or the ability of the metal to not be pulled apart. ( This is where my current set of cast wheels has a crack )

Another graph shows that a wheel with the 'Super Forming' process should be able to endure more stress over more cycles than the typical casting methods do...

So for the engineer a more capable material requires less of it for the same design strength - typically.

I'm shopping for a new set of wheels, and lightness vs. confidence is a concern... Kosei is tempting even if light. I'm thinking track day, auto-x, plus every day use including the odd blast up a dirt road in the wrx..

These on a BRZ seem like an excellent choice.

[JimLill]

Toyota says that the stock wheel weighs 22 lbs. (in the SAE article)

[raventare]

That's only 8 pounds per wheel savings and wouldn't disturb your 7" OEM width. It would also allow 32lbs of added bracing under the car...at least at a standstill, to not disturb the OEM balance. Who knows what it could do for starting, going, stopping, turning and of course mileage.

[Jeredin]

A person named slaxx from FT86CLUB.com has this setup, and this combo is exactly what I'm planning on!

They have 17X7.5 of the OZ Alleggerita HLT, but I'm going for 17X8. I hope there won't be a problem with the TPMS.

This is the picture of their car.


At first I wanted the 18X8, but I think the 17s will be fine for performance and keep the weight down. WRB BRZ and Gold wheels--looks so good.

[JimLill]

I wonder how much the mini spare/tire weighs? Is it possible that a Kosei wheel + tire weighs less and gives you a real spare too?