Hubless Wheel Feasibility Project

[Oldbiscuit]

Bart, I’m no engineer but I’m questioning your roller layout. You keep talking about side plate flex, wouldn’t you eliminate that if your rollers straddled the rim instead of alternating side to side? It would seem that if you had a solid axle that passed through both plates and rollers with no side play in the rollers, the plates would be stiff. What if you made the plate into an upside down u shape ?

 

[The Renaissance Man]

It would seem that if you had a solid axle that passed through both plates and rollers with no side play in the rollers, the plates would be stiff.

I was questioning the offset rollers from the start. Looks like it puts unnecessary stress on the bolts and plates.

 

[BartRidesEternal]

Bart, I’m no engineer but I’m questioning your roller layout. You keep talking about side plate flex, wouldn’t you eliminate that if your rollers straddled the rim instead of alternating side to side? It would seem that if you had a solid axle that passed through both plates and rollers with no side play in the rollers, the plates would be stiff. What if you made the plate into an upside down u shape ?

Thanks for your reply Oldbiscuit! I don't see any issues on your ideas there.
If the rollers make good use of the rims sides, the stiffness of the rim would help keep the base plates in check. I agree.

I was questioning the offset rollers from the start. Looks like it puts unnecessary stress on the bolts and plates.

I agree.
My first concern was the load on the bearing. And bolts/plates are easier to 'strengthen' or stiffen, since they are static.
Yet I chose to go for 'standardized rollers' because customizing from 'staff material' or '3D printing' was much too expensive for my budget. These rollers were the best option that I had in sight.
The lowest roller, which will carry the most weight and stress can have two bearings side-by-side. There is room for that.

In the meantime (pigheaded as I am ) I ordered the plates at a lasercutter.

Lower plates will be 3mm S355 constructional steel.
Upper plates are 5mm aluminum. This also shaves a bit of weight:

• 3mm steel = 140 grams.
• 5mm aluminum = 77 grams.

Next are the shafts.

Load carrying shafts (bottom) will be 10mm steel, CroMoly, something like that. I did thought about it a little bit before ordering the plates though.

• Shafts or roller wheels should be easily replaced, easily adjusted and stay in their position.
• I need the rollers to be adjustable a little bit left to right. So a different rim can be utilized or this rim can properly hold its course

 

[Ulu]

I just went through this whole thread for the first time and three things occurred to me.

A bicycle is such a well perfected machine that we can usually only make it heavier and more complicated and less efficient.

This design replaces an axle & two bearings by several axles and several smaller bearings, & adds a lot of bearing friction.

Now those are skateboard bearings. They come from the small power tool industry.

I have been a skateboarder since 1964, so I know that skateboard bearings get filthy fast and you have to clean them or change them regularly. I had to do that every week when I was riding daily, and nobody greases their bicycle bearings every week. (Except racers and such.)

Having shielded bearings keeps them cleaner but then it also makes it harder to clean them when they get dirty as the shields must be removed.

Bicycle bearings are a foot off the ground, but you’re going to put those skateboard bearings right down there in the dust.

But even worse you’ve got the completely unprotected bearing surfaces between the skateboard wheels and the bicycle rim, which will be constantly getting filthy and rough, adding massive friction to the whole business in a very short period of time.

Now as an art project, I say go for it. You’ll have one of the coolest looking things in town.

But as an engineering project you are trying to uninvent the wheel-on-axle and replace it with the pre-wheel tech of using multiple rollers to move a load.

I predict that after less than 10 miles of riding you will either hang this on the wall or disassemble it for parts to build better machinery.