View Full Version : Interesting Composite Wheels
chavez
08-20-2007, 01:58 PM
Recently I've been researching composite wheels and stumbled across these wheels that I think belong to Tu Fast? Can anyone explain why they did it this way?
http://www4.ncsu.edu/~sdchavka/wheelinside.jpg
http://www4.ncsu.edu/~sdchavka/wheeloutside.jpg
chavez
08-20-2007, 01:58 PM
Recently I've been researching composite wheels and stumbled across these wheels that I think belong to Tu Fast? Can anyone explain why they did it this way?
http://www4.ncsu.edu/~sdchavka/wheelinside.jpg
http://www4.ncsu.edu/~sdchavka/wheeloutside.jpg
flavorPacket
08-20-2007, 02:11 PM
We were across the garage from them and asked the same thing. They said it was for sidewall stiffness/lateral movement of the contact patch
Marshall Grice
08-20-2007, 02:13 PM
You'll know what that flange does once you build a set of carbon wheels and then cut that flange off. http://fsae.com/groupee_common/emoticons/icon_wink.gif
Major stiffness increase.
Travis Garrison
08-21-2007, 02:03 PM
...also the tire puts load into the wheel mostly via a bearing load distribution on the bottom side of the inner bead...that flange would help shell deformation a great deal.
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Travis Garrison:
...also the tire puts load into the wheel mostly via a bearing load distribution on the bottom side of the inner bead...that flange would help shell deformation a great deal. </div></BLOCKQUOTE>
That's true up until a point. You'd have to look at buckling and crippling stresses in the flange.
But I do have to give kudos to them for that design to help with the tire patch. If it worked for them, that's awesome.
Bill Kunst
08-22-2007, 07:46 AM
ooooooo, ooo, oooo, question?????
How do you break the bead to get the tire off? Or is this like formula 1, one time use only?
http://www.flickr.com/photos/ben_michell/1105806559/in/set-72157601415004328/
I'm not gonna charge for use or anything, but credit where credit's due please :-P
I didn't speak to the team specifically about this, but if you have a proper fitting machine it should be fairly easy to fit and strip the tyre because you have one normal height flange and that's all you need.
Ben
Bill Kunst
08-22-2007, 12:47 PM
Yeah, to put the tire on. I have mounted hundreds of tires, and breaking the bead on the flanged side would be, to put it lightly, a little difficult.
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bill Kunst:
Yeah, to put the tire on. I have mounted hundreds of tires, and breaking the bead on the flanged side would be, to put it lightly, a little difficult. </div></BLOCKQUOTE>
Really? I'd have thought you could just compress the top of the sidewall and it would unseat fine.
Ben
Bill, you might want to check out how kart tires are put on and taken off by hand... no machines involved.
Ben, please check your PM's.
Christopher Catto
08-24-2007, 12:33 PM
sorry for sounding a bit dull, but you could have two flanges also just by bolting them on. i know bolts are heavy but anyway if you have carbon rims, then bolted carbon centre (in case you break one or just for simplicity) then the flanges can be part of the assembly. keeping things simple is for me better than the last gram of weight saving. at least thats what racing full size cars teaches you, unless one likes to spend half hours cursing each time the car is in the pits for changes.
saw those wheels in the past two years (in less advanced spec) and they are really nice. machined mag centre would make them much quicker to produce I think. and would in my op be almost as light if the profile of the wheel centre was well made. Dunno how Delft had their wheels this year, I missed FS2007 but maybe same as last year.
John Grego
08-28-2007, 08:20 AM
You'd have to come up with some way of measuring the effect on the spring rate of the tire and how much it effected the contact patch so that you could compensate in your suspension. I think it would probably have the same effect as increasing the air pressure.
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Christopher Catto:
saw those wheels in the past two years (in less advanced spec) and they are really nice. machined mag centre would make them much quicker to produce I think. </div></BLOCKQUOTE>
Really? If you consider how long it would take to cast/machine a mag centre vs the fact that the wheel as shown is a one piece moulded item I suspect your wrong. On the other hand I might be :-p
John: If you just raised air pressure you'd get an increase in vertical as well as lateral spring rate. This wheel would appear to give you an increase in lateral spring rate without increasing vertical rate. As a result you could in theory put a bigger contact patch on the road without decreasing lateral response.
Ben
John Grego
08-28-2007, 05:52 PM
It would give an increase in vertical as well since as the wheel encounters a bump only 1 side of the tire will deflect. So that means its almost doubling your vertical spring rate. It is unlike increasing air pressure since the contact patch in static remains the same (it decreases as pressure goes up).
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by John Grego:
It would give an increase in vertical as well since as the wheel encounters a bump only 1 side of the tire will deflect. So that means its almost doubling your vertical spring rate. It is unlike increasing air pressure since the contact patch in static remains the same (it decreases as pressure goes up). </div></BLOCKQUOTE>
That would be assuming that the tire would have 1 atm of air pressure in it (0 psi gauge) and that all deflection would be handled by the sidewalls. In reality, all of the tire around the contact patch deflects to some significance and the pressure in the tire matters a lot towards the spring rate of the tire at the contact patch.
John Grego
08-28-2007, 06:50 PM
Obviously the pressure has everything to do with the spring rate, I was thinking that putting that flange on the wheel might have a similar effect to increasing pressure.
But, if you put 10 psi in the tire and put the wheel on the ground the pressure will go up. The contact patch deflects more then the rest of the tire expands. Go try it.
Pete Marsh
08-28-2007, 06:53 PM
You could of course just buy a Goodyear tyre that does all this for you. Would be easier and lighter than special wheels trying to do a job that is really the tyres job anyway.
Pete.
John Grego
08-28-2007, 06:55 PM
Exactly, and with the tire consortium data there is no need to make all these assumptions about how the spring rate changes.
Brett Neale
08-29-2007, 04:16 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pete Marsh:
You could of course just buy a Goodyear tyre that does all this for you. Would be easier and lighter than special wheels trying to do a job that is really the tyres job anyway.
Pete. </div></BLOCKQUOTE>
Nice subliminal Goodyear plug there, Pete...
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