Bearing race diameter inequality question

[MrMoe]

TL;DR Summary

Why is my old Schwinn so slow?

Hello all this is my first post. I am not an engineer, but I wish I was. I have been enjoying watching Dan Gelbart!s YouTube Chanel. His air bearing has me wondering about the relationship and apparent conflict inside ball bearings. How does the ball travel around the shorter distance (circumference) of the inner race and the longer distance of the outer races circumference? Is there slippage and friction where the balls contact the races?

 

[Dullard]

The conflict is only 'apparent' - as you accurately state. The balls (ideally) roll without slip on both races - they complete a 'circuit' of the inner race before they complete a circuit of the outer race. As all balls are doing the same thing, that works.

 

[Lnewqban]

Welcome, MrMoe!
For simple bearings that do not have a cage that keeps balls apart, there is slippage and friction among them.

 

[MrMoe]

Very helpful. I think I am starting to get the picture. One trip around the outer race = more than one trip around the inner race. Is this the same concept used to create ratios in planetary gears?

 

[MrMoe]

Welcome, MrMoe!
For simple bearings that do not have a cage that keeps balls apart, there is slippage and friction among them.

Apology` for not noticing the introduction protocol.

I was detected by a bicycle mechanic years ago to remove the caged ball bearings (usually 5 balls) and replace them with 9 loose balls for an upgrade. Could this actually increase friction?

 

[Lnewqban]

Apology` for not noticing the introduction protocol.

I was detected by a bicycle mechanic years ago to remove the caged ball bearings (usually 5 balls) and replace them with 9 loose balls for an upgrade. Could this actually increase friction?

No idea, but good lubrication always help.
The balls-cage friction may be slightly greater than the ball-ball friction in that case, if that is true.