Beefing up an axle- what methods could i use?

[little_sparky]

Hello all,

I am halfway through building a tricycle turned trike called a 'Gladiator Chopper Trike' and have come to a bit of an obstacle that wont effect the build immediately, but I'm a bit iffy about it for the future.

I have a split axle (after really researching I probably should have used a differential but I didn't know I was going to put a motor on it straight away), but the size of the axle is what im worried about, each axle has a 15" commodore car wheel on it with the centres cut out and spoked to the axle, so its not exactly easy to take the tire off to use a 1" or 1 1/4" axle instead.

The two separate axles



The two rims and axles sanded and grinded down, with a bit of paint



The two wheels complete; spoked up with tires on



Axles are connected to the frame with pillow block bearings and two in the middle.



And finally the bike, near completion.


_________________________________________________________________________________________________

So now I ask the question, how can i beef up these axles? with a motor, a heavy rider and speeds around 30km an hour, the last thing you want is for your axle to give way and I'm not going to take the risk unless someone out there is 1000% positive and has proof that this wont break i just cant take the risk.

I will, of course, move the hubs/tires as close to the frame and bearings as I can to reduce that 'leaver' effect. I did think of drilling out a 1 1/4" piece of shaft, drilling from both ends to hollow out as long a piece as I can and then welding it as close to the hub as possible and changing the outside bearing to a 1 1/4" bearing, then drill out another one that would finish flush with the inner bearing and the first piece of drilled out shaft and that would mean that I could either cut a key way or grub screw my sprocket adapter into the 1 1/4" bar without any worries of it breaking on me.

So it would look a little something like this





Thanks
little_sparky

 

[JimDawson]

My biggest concern would be that the axle would break at the weld on the inner spoke hub. That looks like the weak point. Adding a tube over the axle as shown would actually put more stress in that area.

I would build a spool for the hub, and then slide that assembly over the axle. Then you will have to come up with a method of transferring the rotational force. Maybe a chain type coupling like this: http://www.mcmaster.com/#standard-shaft-couplings/=vfyvmv

 

[Dave Smith]

what is the OD size of the current axles?-----Dave

 

[little_sparky]

what is the OD size of the current axles?-----Dave

Sorry Dave i thought i mentioned that, i meant to but left it out, oops! it is a 3/4" axle without a keyway.

My biggest concern would be that the axle would break at the weld on the inner spoke hub. That looks like the weak point. Adding a tube over the axle as shown would actually put more stress in that area.

I would build a spool for the hub, and then slide that assembly over the axle. Then you will have to come up with a method of transferring the rotational force. Maybe a chain type coupling like this: http://www.mcmaster.com/#standard-shaft-couplings/=vfyvmv

This too was a concern in the back of my mind about it breaking or bending at the weld but this just confirms it, thank you

and what exactly do you mean by a spool for the hub? will i have to unspoke it to do that? because although that is an option, it is only one i will refer to if the axle bends or something like that because i will have to repaint the hubs, true up the wheels and put the tires on again which i don't even think it is possible to take the tires off now.

I really really wish that i used a bigger axle and painted the rims a different colour right from the start

Thanks
Little_sparky

 

[chuckorlando]

The axle is gonna bend . Way to thin for all that weight and over hang and being split does not help the cause. I would really use an off the shelf wheel. Well truth be told if I was building that to ride on the street, it would have either dual a-arms or trailing arms, or even a 2link/swinger or 4 link on each side. Spool in the center with a sprocket. Set of cheap VW axles, hubs, in board and out board cv's. All the parts to do a vw rear set up can be had off the shelf for little money

 

[Ebel440]

Is this getting a motorcycle engine or is it more of a bike with a motor? It could make a difference. I see its got cranks already so how many hp is the motor ? What type of steel is the axle made from.

 

[fixit]

Hello all,

I am halfway through building a tricycle turned trike called a 'Gladiator Chopper Trike' and have come to a bit of an obstacle that wont effect the build immediately, but I'm a bit iffy about it for the future.

I have a split axle (after really researching I probably should have used a differential but I didn't know I was going to put a motor on it straight away), but the size of the axle is what im worried about, each axle has a 15" commodore car wheel on it with the centres cut out and spoked to the axle, so its not exactly easy to take the tire off to use a 1" or 1 1/4" axle instead.

The two separate axles

View attachment 92386

The two rims and axles sanded and grinded down, with a bit of paint

View attachment 92387

The two wheels complete; spoked up with tires on

View attachment 92388

Axles are connected to the frame with pillow block bearings and two in the middle.

View attachment 92389

And finally the bike, near completion.

View attachment 92390
_________________________________________________________________________________________________

So now I ask the question, how can i beef up these axles? with a motor, a heavy rider and speeds around 30km an hour, the last thing you want is for your axle to give way and I'm not going to take the risk unless someone out there is 1000% positive and has proof that this wont break i just cant take the risk.

I will, of course, move the hubs/tires as close to the frame and bearings as I can to reduce that 'leaver' effect. I did think of drilling out a 1 1/4" piece of shaft, drilling from both ends to hollow out as long a piece as I can and then welding it as close to the hub as possible and changing the outside bearing to a 1 1/4" bearing, then drill out another one that would finish flush with the inner bearing and the first piece of drilled out shaft and that would mean that I could either cut a key way or grub screw my sprocket adapter into the 1 1/4" bar without any worries of it breaking on me.

So it would look a little something like this

View attachment 92394

View attachment 92395

Thanks
little_sparky

I built a similar scooter. Mine has a 1 inch solid axle with outboard pillow blocks. Wheels have a 3/4 inch bore and are about 8 inches outboard of bearings. I have had no axle breakage. It is driven with a 6 hp Honda 4 cycle engine, really fast (too fast). Major problem is solid axle, drives her straight ahead, she don't like to turn. There is not enough weight on front wheel, My layout looks similar to yours lots of weight on rear tyres light in front. If you install a differential you will solve that problem. I'll try to locate or take a photo.

fixit

 

[little_sparky]

Is this getting a motorcycle engine or is it more of a bike with a motor? It could make a difference. I see its got cranks already so how many hp is the motor ? What type of steel is the axle made from.

it will have a 6.5hp honda engine (gx200) with a torque converter on it so that it takes off slow and is easy on the axle. The axle i believe is just cold rolled mild steel. i am not 100% whether its hot or cold rolled though as i started this project 4 years ago when i was 12.

The axle is gonna bend . Way to thin for all that weight and over hang and being split does not help the cause. I would really use an off the shelf wheel. Well truth be told if I was building that to ride on the street, it would have either dual a-arms or trailing arms, or even a 2link/swinger or 4 link on each side. Spool in the center with a sprocket. Set of cheap VW axles, hubs, in board and out board cv's. All the parts to do a vw rear set up can be had off the shelf for little money

trust me, if i was starting the build right now that's exactly what i would do too, its amazing what you learn in 4 years. But unfortunately i am stuck with this and i really wish i could make the hubs again but i cant :/ I also really really like the look of the spoked wheels, that's sorta what gave me the motivation to try this bike, because i haven't seen anything like it before.

do you reckon there is any way that i could connect cv's to this motor set up and the way i have my axles? even if it meant cutting them and adding splines or something like that? or is it just way out of the picture? (please ignore my ignorance but i have never worked with cv's as of yet but plan to in the near future)

Thanks
little_sparky

 

[little_sparky]

I built a similar scooter. Mine has a 1 inch solid axle with outboard pillow blocks. Wheels have a 3/4 inch bore and are about 8 inches outboard of bearings. I have had no axle breakage. It is driven with a 6 hp Honda 4 cycle engine, really fast (too fast). Major problem is solid axle, drives her straight ahead, she don't like to turn. There is not enough weight on front wheel, My layout looks similar to yours lots of weight on rear tyres light in front. If you install a differential you will solve that problem. I'll try to locate or take a photo.

fixit

I would LOVE to see a pic!

little_sparky

 

[little_sparky]

Here is a CAD drawing of what the rear motor mount will hopefully look like. It will also be adjustable.







little_sparky