Comments by "" (@EbenBransome) on "Munro Live" channel.

  1.  @superspeeder  The example I know of is the Velocette motorcycle crank which ran in taper roller bearings. Slightly higher initial friction was balanced by vastly better bearing life compared to straight rollers or balls, due to the preload taking up wear.
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  2. Unfortunately you have the problem of a wiring harness that has to move up and down with the suspension and is liable to damage from stones, unsprung weight, and the need for an inboard disc brake as otherwise the heat from the brake will damage the motor and its electronics. Hub motors are like the Wankel, people keep thinking it makes sense and then run into the real world problems.
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  3. @ Gears are so 19th century... No, TRBs are far from obsolete.
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  4. The rollers on tapered bearings are indeed tapered. SKF state that their bearings are pure rolling without slip.
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  5.  @JJpleex  You wouldn't notice the difference. If you did, the heat generated would be such that the bearings overheated.
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  6. Herringbone gears were extensively used in marine turbine reduction gears which are basically the same as the ones on an EV, but bigger. The problem with herringbone gears are that they will never be perfectly aligned until they wear sufficiently, and not perfectly even then, meaning that first of all there will be some oscillating axial forces as teeth on both sides don't engage at precisely the same time, but second, regular oil changes are needed until the gears wear in, and that's expensive. In the early days of marine gears there were failures until it was realised a large settling tank was needed for the oil, and magnetic traps, to remove the wear particles. Even filters were not fine enough. Where the power and axial load permits, a single helical gear can avoid this problem, the teeth become polished rather than wearing. Ball bearings are not more efficient because they always have some sliding at the contact line. A correctly designed taper roller has no thrust on the roller ends, and the contact is pure rolling.
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  7.  @konradlindblad7860  There's a plastic material, it's pretty standard stuff. But I suspect in volume they use a precision measuring rig.
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  8. Why? Add lots of cost for no benefit in a low spec vehicle like a car. Aerospace engineering costs many times more than road vehicle engineering. What's the point of a bearing that costs more than the rest of the gearbox?
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