dimensional circle

[Matteo90]

Hello everyone are new to the forum and I already propose you a problem: I have to design a rim, which will mount on a vehicle without motor, with gravitational propulsion, without shock absorbers, whose frame is completely made of wood... the mounted rubber is a full rubber ring, the total weight riders included is on the 220 kg... the rim should be made of aluminum, and using only the lathe, so I do not have the possibility to create races or things like that... and must be as light as possible.. the speeds of these means can also be quite high, about 110 km/h maximum... all the constraints I have written above are provided for by the regulation, so I can't in any way avoid them... Can someone tell me what calculations I can do to make sure the rim doesn't break? I do not have the measurements of the circle behind, but it remains small, I think 15cm in diameter or even less... the bearing that leans on the rim has external diameter 42mm seems to me... I thank everyone who takes the drink to answer. . .
(ps I used the search before opening the discussion but the only thing I found is this http://www.cad3d.it/forum1/showthread.php?t=15298&highlight=cerchioni and I don't think there are the answers I was looking for.. and if there were too difficult for an ignorant like me

 

[Tequila]

I read your post but I don't understand what you need to design!!! gravitational propulsion!!! but since you talk about: all the constraints I have written above are provided by the regulation... so speaking of regulation I assume that it is a means for some race, so post some links or image or design of what you have to do so that we can understand and help you.

Hi.

ps: I also add that it is your first message, to read the forum regulation and to present you

 

[Matteo90]

You're right I didn't show up! However it is, it is means destined to downhill competitions then gravitational propulsion! I forgot that the brakes don't act on the wheels so I don't have any problems letting space to disk or similar calipers. I would just like to know what calculations allow me to size the rim so that it is safe... Hello and thank you. .

 

[Tequila]

Hi, I saw you show up... Welcome to this forum!
As for the rim, we would need more details (post some photos of these machines). you say the tire is a full rubber ring, the size is by regulation or can you mount what you want? diameters, thickness and tread width. then how is it fixed to the aluminum circle? enters by interference, is glued (type that of cars rc). You know we need some details to better understand. I have never dimensioned such things, but here in the forum there are very prepared people and with as much details as possible the answers that will promise you to be given will be more targeted.

as you describe it seems a car of flintstones:biggrin:....without shock absorbers, whose frame is completely made of wood...

 

[MBT]

I turn the question in another way
how did you size the steering wheel and brakes?
because, in the end, not having propulsion your rim will have to endure the combined actions of steering and brakes, more obviously the bumps due to road roughness (unless you do not circumliate on a billiard carpet. . . )

 

[Matteo90]

I know they look like toys. but believe me a low order, the high rigidity gives these means a curved path outside the reach of a normal car... Every now and then we do tests with cars like 'opener' and we often have to stop to avoid dampering. . the rubbers have regulatory dimensions, maximum outer diameter 200 mm... those we use have a 75 mm ground footprint, while in the rear they are always of the same size, but double, coupled as in trucks.. currently the disk is composed of two parts that go to tighten the rubber, we have 3 screws passing that assemble the two disk means and tighten the rubber... Unfortunately at the moment I don't have all the measures, but as soon as I can take them and the places... the brakes are composed of a rubber skate that goes to the ground, downloading practically all the weight of the vehicle plus pilots on the ground, so the wheels do not have that stress. . the steering is very simple, takes into account the angle of hackerman and we can adjust the convergence, which normally is neutral... as soon as I place the drawings of the disks in section with all the odds, that I have at home... in the meantime, thanks to those who answered me and who will answer me