Anybody from Chalmers here? Question about your rims?

[Storbeck]

Quite posibly a stupid question, but how do you get the tire on and off this rim?

I don't see a drop center. Do you have to dissasemble the rim in order to get the tire on and off? Also, what holds the aluminum outer to the carbon inner? Is it just the six allen bolts that can be seen on the outside?

Adalaide's rims seem to be similiar. Anyone from that school here to comment?

http://www.me.chalmers.se/formula/2005%20site/bilder/ar...e/stockholm/falg.jpg (http://www.me.chalmers.se/formula/2005%20site/bilder/archive/stockholm/falg.jpg)

http://students.washington.edu/dennyt/fsae/pdr-aus03/pa...20inner%20wheel.html (http://students.washington.edu/dennyt/fsae/pdr-aus03/pages/Chalmers%20carbon%20inner%20wheel.html)

[Storbeck]

Quite posibly a stupid question, but how do you get the tire on and off this rim?

I don't see a drop center. Do you have to dissasemble the rim in order to get the tire on and off? Also, what holds the aluminum outer to the carbon inner? Is it just the six allen bolts that can be seen on the outside?

Adalaide's rims seem to be similiar. Anyone from that school here to comment?

http://www.me.chalmers.se/formula/2005%20site/bilder/ar...e/stockholm/falg.jpg (http://www.me.chalmers.se/formula/2005%20site/bilder/archive/stockholm/falg.jpg)

http://students.washington.edu/dennyt/fsae/pdr-aus03/pa...20inner%20wheel.html (http://students.washington.edu/dennyt/fsae/pdr-aus03/pages/Chalmers%20carbon%20inner%20wheel.html)

[clausen]

Hi there,

Yes we just copied Chalmers' wheels, but did't do as good a job. Theirs were ridiculously light.

Yes you do take them apart to get the tyre on and off. Not sure about theirs but ours sealed with an o-ring. Theoretically tyres should be easy to swap without needing machinery but they were still a bit of a pain in the arse.

Chalmers had 6 threaded metal inserts that were layed into the carbon. Ours bolted in from the inside using something like 16 screws. Instead of the carbon inner rim, we just had a thin aluminium spinning.

The idea was that you can make a very light wheel with a huge offset (inset, whatever), with lots of calliper clearance because of the lack of a drop centre, hence small scrub radius, no KPI, long wishbones, etc

Regs

[Amos]

Ha! A bit of a pain! Never forget the whole night we spent taking off and putting on tyres to test the spinning!

[Storbeck]

Where did you get the spun aluminum centers without the drop center?

[clausen]

we got them made,

we eventually had a helpful spinner with a modular tool that was nearly wide enough, and we made the end bit of the tool wich was parallel to the desired width and had a 10mm (roughly) chamfer before going down to the bolting face. It takes some careful design to have sealing faces that work and have somewhere for the air to go in. ours ended up heavy because of this. Would have liked to see a chalmers one in bits

[Cooper]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by clausen:
Theirs were ridiculously light.
</div></BLOCKQUOTE>

I don´t see the problem, we still use them http://fsae.com/groupee_common/emoticons/icon_smile.gif

[clausen]

No I certainly wasnt suggesting there was a problem with that fact!

[Cooper]

I think that this years team will use 12 inserts, so that the o-ring will work better.

[Andreas]

Hi!

Havent been on this forum for quite a while and it makes me really happy to see that the three year old design still is remembered.

clausen is perfectly right about those metal inserts that was 5mm thick mild steel with a shape of the "loaf" that can be seen in the second picture in the original post. In UK we used a 2mm oring in a to narrow groove but in Australia we made a proper groove with a 3mm oring (glued oring string) without problems.

The funny thing is I looked for a spinned aluminium ring with a large diameter bolt pattern but that seemed impossible to find. That is how the carbon idea was born. There wasn´t really that much calculations behind that carbon part as I didn´t know how to use the software, sound engineering and prototype testing set the laminate. The laminate of the cylindric part should be stiff enough that it wouldn´t buckle inwards due to air pressure and the tire mating area should be as stiff as possible preventing the rim to be oval under load. The 6 sandwich "loafs" were to axial strength from the bolts. I recall it was 3 or 4 layers of 300gram carbon with quite a lot extra at the tire mating area. The carbon was a total of 500grams

Clausen, I guess I talked to you at the exellent aussie 03 competition and you or someone else at adelaide talked about "copy" design. I haven´t seen it though, do you have a picture?

Regards Andreas, Chalmers -02, -03

[clausen]

Hi Andreas.

Yes I spoke to one of you guys about your wheels just before the 03 Comp when you were having a bit of a test session at the carpark near our uni - in the couple of days before the comp.

I don't have any photos handy, but you should be able to google your way to the current adelaide uni fsae website which should have pics.

Otherwise in the gallery section there is a thread with a few photos of our first testing in that car.