Carbon Fiber Wheels and Wheel Shells

[albino_insect]

I was surfing on a legends site and found this page full of carbon fiber wheels and wheel shells and thought I would share it:
http://www.hyperracing.com/browse.asp?id=830&classid=6&catid=435

I don't see any weights, but they sure do look cool.

[albino_insect]

I was surfing on a legends site and found this page full of carbon fiber wheels and wheel shells and thought I would share it:
http://www.hyperracing.com/browse.asp?id=830&classid=6&catid=435

I don't see any weights, but they sure do look cool.

[Dave M]

they look like injection molded plastic. defenetly not a traditional layup.

[Erich Ohlde]

The wheels are made by a company here in Lawrence. These wheels are indestructible. ATV racers use these all the time, there have even been racers who have ran 5-10 miles in an endurance race on a flat tire with NO damage to the wheel. The wheels do not bend or break, and if they do HiPer will usually replace them (as i believe there is a lifetime guarantee not sure thought).

The company doesn't make 13 inch wheels yet. But I have a feeling if enough people call asking for 13" wheels that our wish might be granted. If you have any questions about these wheels call 877.GO.HIPER and ask for Clancy.

[Wright D]

The wheels might not break, but how much do they flex? Stiffness is important in wheels shell when you want to control camber and tow deflection under loading.

[Jersey Tom]

Those look really odd for carbon fiber. Interesting.

[Erich Ohlde]

These wheels have a very high material stiffness. And they have virtually zero plastic deformation. HiPer did a test where they squeeze a wheel into an egg shape in an arbor press (about one full inch of vertical deformation) and left it overnight in the press. After 2 days out of the arbor press the wheels were back to within their manufacturing tolerance for roundness. These are pretty amazing wheels. and the weight is comparable to an aluminum wheel.

[Travis Garrison]

Tom,

They look odd because they are most likely chopped fibers, lots of plastic parts you handle have chopped carbon in them, so it's nothing new, just a good method to reinforce an injection molded part. The down side is that while I'm sure they are good wheels, their properties aren't going to be anywhere near what they would be with continuous fibers.

[Chris Allbee]

Yeah...until you've actually held one of these wheels and then beat it around, I wouldn't be too quick to judge them. I've seen Erich do things to them that would have ended an aluminum wheel or damaged a more brittle traditional lay-up. Seriously these things are cool.

[Erich Ohlde]

For example:
(devilish grin) How many prepreg carbon wheels would you take and throw as hard as you can at the floor and let them bounce to a stop? This is a demonstration technique that HiPer uses to get peoples attention at trade-shows and ATV races.
-OR- (and this is my personal favorite)
Here is HiPer's old test rig:
(1) 10foot tall steel pipe
(2) pivot bolted to the floor on one end of the pipe
(3) wheel bolted to the free end of the pipe
(4) pipe filled with oil for extra inertia
(5) pull the pipe up to vertical
(6) tip the pipe over and let it bounce
The HiPer wheels have absolutely zero plastic deformation, barely even scratched. They used a comparable Weld, and American Racing wheel (Aluminum) and the wheel was nothing but spare aluminum at the end of the test.

I'll get some pics of the wheel in arbor press in the next couple of days and post them.

[Frank]

IMHO,

13" Carbon outers are best made using 15" and 10" braid..

http://www.uq.edu.au/fsae/Frank/images/teams/2005.jpg

[Wright D]

Plastic deformation? Why would a racecar engineer care about that in a wheel? Why not make the wheel from rubber, and then it would never plastically deform either. Most injected molded plastics can absorb a lot of energy without plastically deforming, but are less stiff then metals.

I am interested in the stiffness and weight.

[Travis Garrison]

Frank,

How did you get your braids? Any chance I could get some pics? garrisont at gmail

[Erich Ohlde]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wright D:
Plastic deformation? Why would a racecar engineer care about that in a wheel? Why not make the wheel from rubber, and then it would never plastically deform either. Most injected molded plastics can absorb a lot of energy without plastically deforming, but are less stiff then metals.

I am interested in the stiffness and weight. </div></BLOCKQUOTE>

Are you serious?

[Storbeck]

We are more concerned with stiffness than strength; by the time you've added enough material to make it stiff enough, it's almost always more than strong enough. FSAE wheels rarely break, and almost never come into contact with solid objects. The thing you have to worry about is stiffness.

Same thing with uprights and chassis.

[Wright D]

Sorry, I should make my posts more straight forward. I was not serious about the rubber wheel. I was serious about the stiffness though. Controlling the amount of unwanted deflection in your car's chassis will allow you to place the tire contact patch closer to the spot that you want it to be (or at least closer to the spot your kinematics tool thinks it is at).

If the wheel were too flexible then it could possibly negate all of that time getting the suspension geometry just right for your car. That is why when I choose components for a racing car I first ask my self what kind of loading it will be under; secondly whether that part should designed/selected for ultimate strength or stiffness.
Examples of the two different scenarios: seatbelt mounts – ultimate strength v. uprights – stiffness.

And since wheels fall into the stiffness design category, I would have to ask myself, what the stiffness to weight ratio of the wheel is???
With out being able to directly test a wheel how might one deduce an estimate? We could look at the material the shell is made out of, and compare it to the material a traditional shell is made of. We might compare the two materials stiffness to weight ratios. The second thing we could look at is the shape of the wheel itself. If the plastic has a lesser stiffness to weight ratio, it might be possible to alter the shape of the wheel shell to create a stiffer shape or a more material efficient shape. The Shape of injected molded plastic can easily be changed from that of the traditional spun wheel shell. It is a change in shape that might have the biggest effect on stiffness, not necessarily the material. It is however the use of a material that allows grater diversity in shape that might make these wheels better. I did notice that the shells had ribs on the out surface of the shells. The ribs looked to be in a radial pattern, and ran from the bolt ring out several inches, right over the highest stressed portion of a wheel shell. Might this change in shape be enough to overcome a loss (if there is one) in material properties by switching from aluminum?

Dose any body know what kind of material the shells are made of? Or rather; dose anybody know the stiffness to weight ratio of the material the wheels are made of? How is the shape different then the traditional spun shell?

One last thing, some teams mount the brake rotors to the hubs in close proximity to the wheels. When heat is conducted to the wheel from the brakes, or tires for that mater, how might the material properties change? How hot is too hot?

Again, apologizes for my previous post. In the future I will try to avoid sarcasm, as it is not easily distinguished when written as apposed to when sarcasm is spoken. One's tone can be heard, but might not be picked up when read. Plus this forum is way to nice a place to come off as an a-hole, which I have been told I can do.

[Erich Ohlde]

well that is all good. BUT these aren't FSAE wheels, they are ATV and Micro-Sprint wheels, and they are concerned with plastic deformation.
When and enduro-ATV racer blows a tire in the middle of a race he will be in a good state of mind knowing that the wheel he has on the axle can take a rock impact or land a jump and not bend and break. Or a Micro-Sprint guy who occasionaly hangs the rearend out a little too far and "nudges" the wall or another car. They don't want their wheels to bend and then cause a leak. Stiffness is good in FSAE wheels, I agree. But these aren't FSAE specific wheels.

[Garlic]

Right. So these are not FSAE wheels. Guess what? Everyone here still cares about how well they apply to FSAE. Not how great they are on an ATV. Nobody could care less about that. FSAE is the topic here, so don't be suprised if it comes up every once in awhile.

I agree these are great Baja wheels, but so far can't see how thwy are better than std. FSAE wheels (seem to weigh about the same)

[Wright D]

This is where I work (http://www.peterdmotorsports.com/), we build dirt circle track cars. Even though our cars only turn one way(left), and run on the dirt, stiffness of the chassis and suspension is still important to us, for the same reasons as in fsae.

The cars weigh in at 1000 lb. (rules mandated, we bolt on about 150 lb of ballast) and are powered with 1000-1300 cc high performance street bike motors.

I am going to set up a car for a solo 2 event, I think it will be fun. I will have to get tires, and take out the ballast of course.

One more stupid rule we have to fallow; we have to run steel wheels. How crappy is that!! But even the steel wheels get trashed when running them up against walls and other cars, it would interesting to see how a plastic would perform in those types of conditions. They could possibly out perform the steels that we are forced to run.

[Chris Allbee]

garlic obviously isn't concerned about coming off as an a**hole...I still believe that those wheels have some potential if the material and shape were fitted to FSAE. THAT seems to be the way Wright D was thinking...about the material and design application...you know, engineering thoughts...not just a random bash from the local village idiot (garlic).

[Garlic]

Yea, anyone that blasts someone is an idiot. (see above) http://fsae.com/groupee_common/emoticons/icon_wink.gif

No i don't care if I come across as an ahole, but of course, that's not my point, either. Obviously you don't either with a post like that. We have a lot in common!

It's nice when formalities are left by the wayside because sh*t gets done! I make plenty of engineering points but if I think somethings dumb I say so.

The stiffness question had been beaten around the bush about 5 times, overrun with glowing reports of how indestrucatble these things are.

[Chris Allbee]

i know i'm an a-hole. I don't deny it. I still think that a more FSAE friendly geometry with this material would be stiff enough and light enough to justify its use. If anything because they aren't as prone to cracking as the kaizers when installing tires.