Enkei Rims material Question

[Vishnuatepork]

I will presume this Q goes out to all the machinists and riders.

I am trying to determine the kind of Aluminum Enkei Japan used in making the cast Alu wheels for my bike.

Suzuki VX800.  1990 cast alu...over 1/4" thick

They are heavy as all heck, and the question came up while talking to my machinist.  He said that they are made as light as they can be (at nearly 20# for the rim alone...he sees the world differently).  He seems to think that the engineers would never add unwanted weight...ya right....

Anyone recommend where to get a block of alu that is 6151-t6 about 20"x20"x5"?  I can get my cad programming/machining done free.  And I am curious to know what the cost would be...

Cheers
Alan

[MTABike]

Alan,
I used to buy big chunks of Al from these guys for machining projects at college. 
http://alreco.biz/
Have also called and had them ship me stuff I needed but couldn't source here in MT from CO.  There yard is quite a site, and there prices have always been reasonable.  I'm not sure that there would be anything reasonable about shipping that 195 lb chunk of Al across town, let alone cross country.
Good luck,
Scott

[Stainless1]

If you plan to machine a wheel, why 6151?  7050 stable plate might be a better choice.  Lots of large airplane parts that start as 200-300 lbs and end as 20 to 30 use that one... removing lots of material sometimes make parts warp.  The Yard in Wichita is also a good spot for thick al plate.  I think most of it is around $1.50 a pound.  



btw, Bob at ALRECO is a landspeed racer, ran a roadster I think.... still goes every year...

[Vishnuatepork]

The reason for going with 6151 is this>>>>

http://www.forged-wheel.com/About.htm

These guys make one of the lightest rims in ALu known to man.  I will base my designs off of what they do, there is enough info/pics around the net to make a pretty good CAD, I'll be a bit heavier but thats cuz I want them to last a while too .  I am open to suggestions on material!!!  I dont know enough about this, and would love some help.

Correct me if I'm wrong but doesnt the 7000 series alu require heat treatment/aging?
 

I spoke with my machinist again today.  He didnt realize how serious I am with this....  He's going to look at local sourcing of the 6151.....sucker shouldnt have offered his time for free

cheers
alan

[Peter Jack]

If you're planning to use the bike for Bonneville, maybe you shouldn't be looking at lightening the rims at all. It's really common to add significant weight to the swingarm to aid traction. By lightening the rim it would just mean that you'd have to add more to the swingarm. The flywheel effect doesn't hurt either as you have enough distance to accelerate the heavier wheel to ultimate speed and the extra gyro effect should add to stability. Just a thought that might save considerable expense.

Pete

[Saltfever]

Thanks for the link to the web site. Notice that they make a big deal about FORGING! They are proud of the fact their wheels are forgings. A forging takes blank stock and hammers it into a near net shape. Then finished machining is applied and that is the final product you see. You will not get the same material properties by just machining a non-forged blank of 6151. Forging dies could cost $15k-$20k. There may be alloys better suited to your needs if you are considering just machining to net shape.

[gearheadeh]

If you're planning to use the bike for Bonneville, maybe you shouldn't be looking at lightening the rims at all. It's really common to add significant weight to the swingarm to aid traction. By lightening the rim it would just mean that you'd have to add more to the swingarm. The flywheel effect doesn't hurt either as you have enough distance to accelerate the heavier wheel to ultimate speed and the extra gyro effect should add to stability. Just a thought that might save considerable expense.

Pete

Pete, something worth debating!
 Heavy car/bike.....Heavy flywheel for sure to slow down the effect of too much torque breaking the tires loose....Litest possible tire and rim to enable the tire to slow down and regain traction once it is lost!
Guys ....is this correct?

[Vishnuatepork]

I'm not planning on Bonneville, but Mojave.  When all is said and done, it'll likely be a track bike. 

I guess I dont understand the manufacturing as much as I thought.  So they stamp it before machining it?  Ugh, so much for that idea.  Unless another alu would work??  I guess its back to modifying swing arms and drive shafts.......ugh!!!!!!

[Peter Jack]

I don't see any reason to debate it. It's a person's choice to take what ever information is offered and either reject it or try it. The only way you'll ever find out the truth is to test. Theoretical ideas only result in theoretical results.

Pete

[MTABike]

Alan,
Do some "googling" about forging.  You might include the term "grain structure"  in such a search.  It would probably help you get your head around the whats and whys of the process.  There are a lot of wheels that are simply carved out of a big hunk of metal, although they are typically for custom chopper type of bikes and I'm not sure if the blanks are forged into a rough wheel shape first or not.  If you have "free" CAD work available, you might ask if they can also perform finite element analysis on the design to get a rough guess about stresses in such a wheel and weather or not it would hold up.  I'm a complete rookie when it comes to land speed racing, but I can't see the advantage to adding unsprung rotating weight on any bike.  Seems to me like the fastest bikes have fairly light wheels.  Take my unqualified opinion for what it's worth...
~Scott

[Peter Jack]

I come from a background of oval track, road racing and a little drag racing. At all of those venues light weight was important and light unsprung weight was really important. I still have problems agreeing with what appears to work at Bonneville but if you check out a lot of the record holding vehicles you'll find that very often weight is your friend and unsprung weight seems to have little importance in most cases. My inclination is still to build light and add ballast as needed but we probably don't need to go to the extremes to save weight that we do in other forms of racing.

I think the salt and its lower coefficient of friction plus the relatively smooth surface provided are the reasons for the difference.

Pete