Fusion360 stress testing?

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Hummina Shadeeba   10 MW

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Fusion360 stress testing?

Post by Hummina Shadeeba » Jan 21 2022 2:14pm

I’m doing a version of the “Russian illegal bike”, which I think is a great design, but instead of using the common 1500 watt hub I’ll be making the motor and using either a common aluminum 12mm thru axle or getting it made in chromoly.

The frame will be carbon with foam core and I can figure that out and don’t need help with that and the motor is simple enough but the custom swing arm (which I still have to add bracing to and the mount for the shock) and this thru axle and the aluminum plates it goes through I wonder how bulky to make it.


A standard quick release isn’t an axle and the wheel is supported by the hub as it sits in groves in the frame and fork but I hear the frames and forks that use a thru axle have a lot of variation in dimensions of the slot the hub fits in and the wheel is not supported by hub connection in this slot and ultimately thru axle wheels are sitting on the thru axle. I plan to have 11mm bearings sitting on the thru axle and those will be the stressed points.

I have to add trusses to the swing arms as well and really all aspects of it are made flying blind

Is there a good guide to stress testing and specifically what kind of loading and torsion should I expect on a bike?
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mxlemming   10 kW

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Re: Fusion360 stress testing?

Post by mxlemming » Jan 23 2022 7:20pm

Is that thing you've drawn a belt or the swing arm?

It'll need to be like 10x thicker if a swing arm and the rear will need a massive pulley if it's a belt.

Use tubes for the rear swing arm.

Bank on 30kg side load on the tyre causing les than 10cm deflection on the wheel as a reasonable starting point. I measured about this much on a few of my full suspension bikes.

12mm through axles are common.
Hold my beer while I divide by zero :flame:

Hummina Shadeeba   10 MW

10 MW
Posts: 2393
Joined: Apr 25 2014 10:26pm
Location: Sausalito

Re: Fusion360 stress testing?

Post by Hummina Shadeeba » Jan 23 2022 7:53pm

mxlemming wrote:
Jan 23 2022 7:20pm
Is that thing you've drawn a belt or the swing arm?

It'll need to be like 10x thicker if a swing arm and the rear will need a massive pulley if it's a belt.

Use tubes for the rear swing arm.

Bank on 30kg side load on the tyre causing les than 10cm deflection on the wheel as a reasonable starting point. I measured about this much on a few of my full suspension bikes.

12mm through axles are common.

It’s a hollow swingarm. 20x30mm at the thin end. I was planning to add trusses and a brace to mount the shock. It more so shows how the motor n bearings mount and how the steel dropouts will connect . If u know anywhere that could weld tubes for the swing arm that sounds more appropriate and likely cheaper.

Thanks for a common deflection of the wheel. I guess I could add a found wheel design off thingiverse or somewhere to add to my design to test.

12mm aluminum thru axles are common and I guess strong enough and no need for custom and steel. I have yet to get ahold of one and confirm it is a true 12mm shaft for a bearing and hate to have any play.

mxlemming   10 kW

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Re: Fusion360 stress testing?

Post by mxlemming » Jan 24 2022 4:16am

They are true 12mm and the ones i have run directly inside the bearings with minimal play.
Hold my beer while I divide by zero :flame:

Hummina Shadeeba   10 MW

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Posts: 2393
Joined: Apr 25 2014 10:26pm
Location: Sausalito

Re: Fusion360 stress testing?

Post by Hummina Shadeeba » Jan 24 2022 10:34am

When u say what u have fit in a bearing w minimal play.. you mean u slid a 12mm bore bearing on one? I think with a typical thru axle the hub is sitting on the axle and with a hair of clearance design into it for it to be easy to slide the axle in and the bearings are between two parts of the hub, no?

I used to have a thru axle bike but no longer

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