Curious About The Axle Collar

Piece 19 is an axle collar, and I have no idea why it's there. It doesn't space the bearings apart since each bearing sits on a shoulder. The collar ID is about .018" larger than the axle OD, so it doesn't support the axle, although its name suggests it has something to do with it.

Does anyone have any idea what its function is? I'm not losing sleep over it, but it sure has me baffled.

Once it is fitted it supports the center of each wheel bearing to reduce side load and potential collapse, and to make a complete outer sleeve for the axle.

jstrummer said:

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Piece 19 is an axle collar, and I have no idea why it's there. It doesn't space the bearings apart since each bearing OUTER sits on a shoulder. The collar ID is about .018" larger than the axle OD, so it doesn't support the axle, although its name suggests it has something to do with it.

Does anyone have any idea what its function is? I'm not losing sleep over it, but it sure has me baffled.

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It DOES distance and clamp the bearings INNER races once ALL the bits and collars are assembled and the axle torqued.....
None of those central parts can then rotate, (they form a rigid "tube" when clamped by the axle) while the wheel (with the pressed-in bearing outer races) can rotate around (the "tube") on the rolling balls.....

jstrummer,that distance collar/center tube part is important and works together with your wheel bearings.The 2 wheel bearings really need to be carefully seated against it and once the axle is torqued to spec,the bearings are supposed to sit spaced inside there with no side-load stress to them after tightening the axle.The thing you want to avoid in your wheel is tightening the axle and binding(they both need to fit snug inside the hub,but evenly spaced to where that 'tube' keeps them unloaded and free-spinning) the bearings up.. they both need to move freely and smoothly.When you install the bearings/tube,care must be taken to be sure of this before you install the wheel and torque the axle:keep lightly tapping the outer edges of each bearing until you are pleased that the distance collar/tube is somewhat snug between the bearings and both bearings are allowed to spin freely as an assembly.I hate to see you burn-up a wheel bearing.

When I do this procedure on a wheel,I test the feel of how free-spinning the bearings both are by trying to spin either side with my finger:it shouldn't feel tight while trying to spin them.

Thank you all for your explanations. They actually made me smile. I enjoy learning things. And thank you bilbikek441 for the installation instructions. They'll certainly be followed when I put the wheel back together.

I love this forum...I just flipped open my computer to ask exactly the same questions as the OP did way back when. The answers make perfect sense however I have a slightly different scenario in that the spacer inside my hub is about 4mm shorter than the distance between the inner races. I foolishly thought I would undertake something simple today. I guess there's no such thing when working on these old bikes. I have another complete set of wheels that I didn't use because the rims were in rough shape. I guess I'm going to have to pull the 2nd wheel apart and hope that the collar inside will fit better.

Troy said:

I love this forum...I just flipped open my computer to ask exactly the same questions as the OP did way back when. The answers make perfect sense however I have a slightly different scenario in that the spacer inside my hub is about 4mm shorter than the distance between the inner races. I foolishly thought I would undertake something simple today. I guess there's no such thing when working on these old bikes. I have another complete set of wheels that I didn't use because the rims were in rough shape. I guess I'm going to have to pull the 2nd wheel apart and hope that the collar inside will fit better.

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First, thanks... you should start a new thread for yours and post some pictures because unless the PO lost the original spacer tube between the bearings and used another one that wasn't correct length, it shouldn't be like that and we need to get to the bottom of it.

A real life scenario when this spacer is omitted and ancientdad saved the day in hunting down the issue.

I picked up a bike and rode it around and one day the rear wheel seized just as I was pulling off the highway. Locked up solid and needed 2 motorists help to drag it off the road. The brake plate was jammed against the hub, and I was able to loosen the axle nut and rode it home. With ancientdads help was able to track down the spacer issue, installed it and been spinning fine ever since

MrPepper said:

A real life scenario when this spacer is omitted and ancientdad saved the day in hunting down the issue.

I picked up a bike and rode it around and one day the rear wheel seized just as I was pulling off the highway. Locked up solid and needed 2 motorists help to drag it off the road. The brake plate was jammed against the hub, and I was able to loosen the axle nut and rode it home. With ancientdads help was able to track down the spacer issue, installed it and been spinning fine ever since

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That must have been a few years ago Chris, I can't recall the incident but I'm glad it came out okay.