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27

I think several of your assumptions are incorrect: no high speeds: rim dynamos spin quite fast, up to 10,000rpm, and that does require effort on the part of the designers. Typically the drive wheel on those will have a radius of about 1cm, or a circumference of 3 1/3rd cm and 30 revolutions per metre. At 10m/s (30kph) that means 300rps or 18000 rpm. This ...


18

The short answer to your first question is "the power savings from using ceramic bearings compared to good steel bearings is almost zero." The short answer to your second question is "yes, it is possible to measure the difference but it's not easy." The longer answer, and the support for the shorter answers is below. First, however, it depends a little on ...


10

Anti-sieze is a corrosion preventer. It is not a lubricant. Generally, using it on threaded parts is acceptable, but using it on bearing races, bearings, pressfit installation points, seatposts, handlebar stems, etc... is not a good idea. There is no hard and fast rule, but if you think about the purpose of the "lubricant" on the specific part, you should ...


10

Firstly I disagree with the comment about high speed. The highest velocity bearings are plain: crankshaft bearings in a full size car engine are plain, whereas in a radio controlled model, ball bearings are used. Where velocity (rpm x diameter) is high the oil wedge effect tends to centre the shaft (hydrodynamic lubrication). This can be further enhanced if ...


8

There are several possible causes of noises you can get from your bottom bracket. Bad bottom-bracket bearings Bad pedal bearings Loose crank arms Loose bottom-bracket cartridge Loose chainrings Of these the loose crank arm (which may be silent or may be accompanied by a creak on each stroke) is probably the one needing the most immediate attention, since ...


7

It's not unusual for an asymmetric shaft (on some rear wheels or solid-crank bottom brackets, eg) to have different numbers of balls in one side vs the other. But it's a little unusual for a standard front hub. And if there's intentionally a difference then there would be a small but visible difference in the size of the races as well. Likely the hub was ...


7

First, not all full suspension bikes use bearing for all pivot points, and some bikes don't use them for any. They use bushings instead. That said, assuming you have bearings at all points on your bike: There are 2 types of bearings damage which require replacement in a suspension system. The first, bearing play, means lateral movement inside the bearing ...


6

It sounds like your headset is not adjusted. Your stem cap is used to adjust this. Specifically, the more you tighten the stem cap, the tighter the bearings will get, and the less play you will feel. Here is a picture from Sheldon Brown's article on adjust headsets: My process for checking headset adjustment: Check the headset adjust: Grab the front ...


6

I would recommend doing two things: Reassemble the hub with the thickest grease you can find (within reason). It might slow you down a little, but it will help the bearings last as long as possible. Make a mark on the back side of the cone that corresponds to where the damage is. When you're putting the wheel on, rotate the axle so that the damaged side of ...


6

Probably never -- headsets can easily last the life of a bicycle for most people without needing an overhaul. If you ride in the wet, it is advisable to have a front fender, though (to reduce the likelihood of needing an overhaul even further).


5

I don't have the source at hand, but from what I've read, converting your wheel bearings to ceramic will net you something like a 1 W savings at racing speeds, thanks to reduced mechanical losses. A ceramic bottom bracket would result in less improvement. Considering the rider is putting out 200+ W at racing speed, the savings are clearly minor. Additional ...


5

The common Shimano Dynamo hubs don't actually use sealed cartridge bearings, see the DH-3N71 and DH-3D72 techdocs. Shimano dynohubs do use good seals, however, and should hopefully be maintenance-free for many thousands of miles. Alistair Spence has a good exploded view of an Alfine DH-S500, which is very similar to the DH-3D71. He also links there to a ...


5

Possible options could be Damaged bearings Bearing closed too tight Bent axle Spoke that touches the axle (I had it once when I put a straightened j spoke instead a straight pull one).


5

That looks fixable to me. What probably happened is the locknut was loose, and continued riding caused both cone and locknut to unscrew. It's a good job you've stopped riding that bike - riding on that hub now would cause significant damage. When a hub has a bit of play, the balls are free to move across parts of the cup and cone that aren't designed to ...


5

A bearing that is adjusted too tight can actually seize completely. This happened to me once. I overhauled my front hub and tightened the bearing cones too much. Result: a front wheel that plain stopped turning at some point. Too tight adjustment will exert more pressure on the cones and cups, and will probably wear out the bearings faster than too loose ...


5

Gasoline was used for many years as an inexpensive readily available solvent. There are a couple of real life issues with using gasoline for a solvent. It is very flammable thus a fire hazard. It is absorbed through the skin and it is toxic when inhaled in high concentrations. You have to find a way of disposing of the remaining dirty solvent. Pouring it on ...


5

That is old grease with debris in it, this will be shavings of the bearings and their channel. Before re-greasing the headset you will need to degrease it to remove all of the old grease, otherwise the old grease will attack the new grease rendering it less effective. Then once degreased you will then need to clean out all of the degreaser (again so it ...


5

With a trapped axle like that you use a hammer, ideally a soft face one or I use a bit of wood as a pad. Hold the block against the axle, tap the block with a hammer. Holding the wheel in your hand rather than blocking it against a solid surface also reduces the impact. You will still probably damage the bearings, so preferably don't do this until you have ...


5

Buy and fit new ball bearings. They're under $5NZ $4US for a set. Its false economy to not replace them when the headset is open. Headset bearings are probably best in retainers rather than loose bearings. They don't roll a lot compared to wheel or BB bearings, and there's a lot of small bearings around a relatively large race compared to wheels.


5

Summary: buying just the dust-cap is unlikely, normally you buy new cones and often a new axle, but that's because new cones are cheap. You'd only buy a new hub if something else is damaged (rare). You won't be able to fit sealed bearings. I the picture below from the Park site is the bearing cone and cap. I assume that's the cap you're talking about? ...


4

First of all, good on you for having a go at proper bike maintenance. Unless you have an expensive American Classic or other 'pro' hub you will be needing 10 3/16 inch balls on either side of that front hub of yours. Typically these are available from your Local Bike Shop in a pack that will have a few spares for the ones that run away whilst you put them ...


4

Some pedals are designed to be disposable, with sealed bearings as you mentioned. Usually these have a plastic dust cap (the cap you referred to) which is not easy to remove. If this is the case, you won't be able to do anything with the pedal, even if you get the cap off. Typically, as you seem to know, if a pedal is designed to be serviceable, there will ...


4

I have ridden ceramic BB bearings. This is my one and only experience. They seemed to take a couple rides to break-in which definitely seemed odd. One of my training partners noticed the same thing, but in his case, it was after 90 minutes that the bearings seemed to spin freely. I rode them for just shy of a year, which is approximately the same usage I ...


4

Pick the bike up so the problem wheel is off the ground. Grasp the tire and push it back and forth (left/right relative to the frame). If you can get any perceptible motion then the bearings are loose and need adjustment. While the wheel is off the ground, spin it and watch the space between the rim and the brake block (assuming you don't have disk brakes)...


4

Yes, you can. You just need to get the right size of loose ceramic ball bearings as that's what shimano wheels use. They are available from various vendors, like here for instance. You didn't ask this, but I'll answer it for you anyway: would I recommend replacing the bearings on a pair of WH-R550's with ceramic bearings? No, and neither would many others. ...


4

I've also never seen a bearing ball fail like that. In Jahaziel's answer to this question: When do bearings need to be replaced? he notes that in Honduras where he lives they sometimes could only get cheap Chinese bearings that "used to 'peel off' like an onion". Perhaps you got some of those? See also the response of "Mike" in this thread [1], who had ...


4

In replacing a threaded headset on an older bike, there are two other considerations we need to make beyond selecting between ball bearings or needle bearings (though, IMO needle bearings are ideal for a number of reasons that I won't get into.) First, you need to measure the stack height. Stack height is the amount of space the headset takes up, not ...



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