purpose of this part

[chickenStripCharlie]

Hi guys,
Does anyone know the purpose of this part on a 93 honda nighthawk wheel?

Part #6 below. It is pressed into a 20mm ID bearing (on the cush drive) to turn that bearing to 17mm ID. I am not able to figure out why they wouldn't have just used a 17mm ID bearing like they did for the other two wheel bearings.

Can someone explain it to me? It protrudes out of the bearing some 5mm or so. Is this just to help with axle alignment when sliding the axle in ... to take up that gap between the wheel bearing and cush bearing, or what?

I'm swapping this 93 wheel onto my 83 and was just going to get new bearings that are same OD but 20mm ID to accept '83 axle. Then i noticed that part on the cush bearing.

 

[Streetfighterkz]

Can someone explain it to me? It protrudes out of the bearing some 5mm or so. Is this just to help with axle alignment when sliding the axle in ... to take up that gap between the wheel bearing and cush bearing, or what?

It takes up the gap between the bearing in the sprocket carrier and wheel bearing. The way it’s shaped is because it needs to be captive so it doesn’t fall out when the wheel is being installed or removed.

Later, Doug

 

[chickenStripCharlie]

It takes up the gap between the bearing in the sprocket carrier and wheel bearing. The way it’s shaped is because it needs to be captive so it doesn’t fall out when the wheel is being installed or removed.

Later, Doug

Right, but why? Why couldn't have they just used a 17mm ID bearing like the other 2 wheel bearings? Who cares if there is a gap between the cush drive bearing and wheel bearing that needs to be taken up?

The part is pressed into the bearing and wouldn't myst "fall out"

 

[Streetfighterkz]

Right, but why? Why couldn't have they just used a 17mm ID bearing like the other 2 wheel bearings? Who cares if there is a gap between the cush drive bearing and wheel bearing that needs to be taken up?

Roller ball bearings are not really designed to take axial (thrust) loading only radial loading. If there was no spacer between the bearings as you tighten the axle nut, the gap would close and create an axial load in the bearing(s). This would prematurely wear the bearings at the very least. The less side loading of a typical roller ball bearing the better.

Later, Doug

 

[chickenStripCharlie]

Roller ball bearings are not really designed to take axial (thrust) loading only radial loading. If there was no spacer between the bearings as you tighten the axle nut, the gap would close and create an axial load in the bearing(s). This would prematurely wear the bearings at the very least. The less side loading of a typical roller ball bearing the better.

Later, Doug

Right, that makes sense.... but why, then, is the spacer in between the two main wheel bearings loose? Why is it not tight against the two bearing races that sit in the wheel hub?

I assume it's possible once everything is tightened that there is no gap, but seems like a lot of gap to take up?

Thanks for the replies. I guess I have a third spacer to make now as well.

 

[jpmobius]

All assemblies of this sort are the same. The idea is to create a solid structural element out of the axle. Imagine taking the bearings apart so you only have the inner races. When you assemble all the components together and tighten the center bolt (axle) down, you create a ridged beam that connects the two swing arm legs. The wheel simply spins around it. This is why it is critical to have ALL the correct components correctly assembled. There HAS to be a correct spacer between the two wheel bearings as well as your sleeve (part#6) stacked up with the inner bearing races and the rest so that the center bolt can be brought tight. Likely the manufacturer intends the drive hub to somewhat "float" axially in the assembly so that it is not constrained by anything other than the drive bushings. Your front wheel is exactly the same sans the drive hub, as the brake rotors need no shock absorbers like the drive hub which is there to protect the driveline and transmission. The axle assembly clamps the lower fork legs together so the entire assembly behaves like a single component moving up and down following the road. Likewise, your swing arm pivot is also designed the same. The center bearing components should be clamped completely tight into the frame, with the arm shimmed to zero play spinning around the assembly.

 

[chickenStripCharlie]

All assemblies of this sort are the same. The idea is to create a solid structural element out of the axle. Imagine taking the bearings apart so you only have the inner races. When you assemble all the components together and tighten the center bolt (axle) down, you create a ridged beam that connects the two swing arm legs. The wheel simply spins around it. This is why it is critical to have ALL the correct components correctly assembled. There HAS to be a correct spacer between the two wheel bearings as well as your sleeve (part#6) stacked up with the inner bearing races and the rest so that the center bolt can be brought tight. Likely the manufacturer intends the drive hub to somewhat "float" axially in the assembly so that it is not constrained by anything other than the drive bushings. Your front wheel is exactly the same sans the drive hub, as the brake rotors need no shock absorbers like the drive hub which is there to protect the driveline and transmission. The axle assembly clamps the lower fork legs together so the entire assembly behaves like a single component moving up and down following the road. Likewise, your swing arm pivot is also designed the same. The center bearing components should be clamped completely tight into the frame, with the arm shimmed to zero play spinning around the assembly.

I understand that, but i still don't see how the bearing spacer is as loose as it is. With the bearings seated as far as they can toward each other in the hub there is still some gap between them and the spacer. I don't think this gap can be taken up when everything is tightened up since the bearings are already seated as far into the hub as possible.

So, how does that work as far as making everything one rigid piece?

(The gap i'm talking about, is the gap where you would put your punch to drive out the wheel bearings)

 

[chickenStripCharlie]

Update ... there is no gap in the spacer. It's as it should be. The gap I noticed was just bad lighting and two heavily beveled edges that felt like a gap. My mistake. Thanks again for the help!