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60 votes
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Why do men's bicycles have a top tube while women's bicycles don't?

Frames designed for women do have that part - its called a top tube. Historically women wore skirts, so a lower frame in the middle made it easier to mount and dismount, and was less likely to ...
Criggie's user avatar
  • 126k
39 votes

Why do men's bicycles have a top tube while women's bicycles don't?

Back in the day, women primarily wore dresses, and getting the dress over the top tube was difficult and awkward. So the women's bike was developed with a slanted or sloped top tube so women could ...
lulubelle's user avatar
  • 714
19 votes

Pedal spin resistance a good thing?

There does seem to be an upside down U-curve of spinniness on pedals with the horizontal axis being price and the vertical axle being how many rotations it makes when spun by hand. Cheap pedals are ...
RoboKaren's user avatar
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12 votes
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Choosing the proper bearings for replacement

Bearings are of standardised dimensions. In your case 6902 is 15 x 28 x 7 (inner diameter x outer diameter x width) and 6903 is 17 x 30 x 7 (which you probably got from Google). Thus, dimension-wise, ...
Mike's user avatar
  • 4,331
12 votes
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Got a new frameset, don't know why I need this split ring collar?

That looks like the compression ring for a threadless headset. Images by keithonearth on Wikimedia Commons, reproduced under Gnu free documentation license More information found at Sheldon Brown
David D's user avatar
  • 21.9k
10 votes

What is "crank preload"

Good question. This is a term that is frequently referred to but not clearly defined. I added a definition of preload to the terminology index under the bearings page. Consider your crankset. Preload ...
Weiwen Ng's user avatar
  • 32.7k
10 votes
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Pedal: Platform came off axle which remained in crank

I found a component diagram for these pedals here. Here's the main diagram: Looks like all the bearings are mounted onto the axle and secured with a bearing preload and lock nut at the outboard end. ...
Argenti Apparatus's user avatar
10 votes
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What range of rotational speed for bike wheel bearings?

Searching for "ndm rotational speed" finds that D and d are outer and inner diameters of the bearing. n is not the usual symbol for speed, but neither is the final unit "millimeters per minute divided ...
ojs's user avatar
  • 22.2k
10 votes

Chain is jumping regularly on every cog at every speed?

When cogs are worn, new chain makes things worse. In my case, the old chain was skipping time to time but the bicycle was rideable. With the new chain the two fastest gears went completely unusable. ...
nightrider's user avatar
  • 7,879
10 votes

Can QR cause Brinelling in hub bearing?

Brinelling happens when the contact stress exceeds the limit of the material. I don't believe you can achieve that alone with a too tight QR, although it sounds like your bearings are so tight that ...
juhist's user avatar
  • 19.4k
9 votes

Pedal spin resistance a good thing?

The difference is in the lubricant. Ball bearings need to be lubricated with a sort of grease. This grease is in your wheel hubs and also in your pedal bearings. The grease is gooey. Gooeyness ...
Daniel R Hicks's user avatar
9 votes

Got a new frameset, don't know why I need this split ring collar?

It is indeed a compression ring, David D’s diagram is helpful to illustrate the following: What it does is transfer the force of the cap bolt to the inner face of the cartridge bearing. That then ...
Swifty's user avatar
  • 12.8k
9 votes
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Off brand bearings for hubs?

With bike hubs you are generally safe buying a high-quality generic replacement as long as it's actually the same bearing type, same dimensions, same kind of shields, and with 100%-ish grease fill. ...
Nathan Knutson's user avatar
9 votes

Do I need to remove this DT Swiss ring nut? (360 hub)

DT Swiss states that on pawl type rear hubs, the ring nut must be removed in order to remove the driver-side bearing. See section 2.7, page 9, in this manual from DT Swiss: https://www.dtswiss.com/pmt/...
MagnusK's user avatar
  • 846
9 votes

Is this a sign for bearing maintenance?

I've never been in this situation, but here is my opinion. I would take the fork out, or have the store do it, and inspect things. You can check if your bearings feel gritty, which indicates wear. If ...
Weiwen Ng's user avatar
  • 32.7k
8 votes
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Can I replace this bearing? (MTB head tube)

It's the most common kind of threadless headset. External cups, caged bearings. It uses a 5/32x20 retainer (bearing size x count), which again is the most common type and available online and at most ...
Nathan Knutson's user avatar
8 votes
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Dent in bearing cone, try to get a new one, or can I keep riding like this?

Anywhere there is a cone, there is also a "race" that the bearings sit in. The cone holds the bearings in place against the race. The picture you have posted shows the very definition of "pitted cone"....
Gary.Ray's user avatar
  • 16.4k
8 votes
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Front wheel bearings change

Put the 3/16" bearings back in, even if you have to buy some fresh ones. Your quarter-inch bearings are not sitting in the bearing raceway right which is causing the too tight/loose problem. They ...
Criggie's user avatar
  • 126k
8 votes
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Should there be grease in my steel frame's tubes?

Some mechanic might have put a liberal amount of grease in the BB shell and also in the head-tube prior to assembly. Then copiously greased the seat-post as well. Grease has a tendency to migrate, ...
Carel's user avatar
  • 8,309
8 votes

Just replaced axle on rear wheel. It is loose at first but as soon as I ride it, it tightens and wheel no longer rotates. Help!

I have sometimes made the mistake of not tightening the locknuts enough, causing the rotation of bearings to drag the cone, tightening it enough for the bearing to bind. The solution is to properly ...
Jahaziel's user avatar
  • 12.5k
8 votes
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How/where can I find replacements for these 'wheel bearing caps'?

Metal dust shields would be the common name to the extent there is one. The usual protocol is to handle them with care and never remove them, because they're difficult to replace. The OEM hub ...
Nathan Knutson's user avatar
8 votes

Cup and cone bearings: better a little tight or a little loose?

As loose as possible without play. Bearings are supposed to have some amount of preload, which is a fancy name for being a bit tight as opposed to being loose. There should never be play once adjusted ...
Nathan Knutson's user avatar
8 votes
Accepted

How is the load of the bike transferred to the hub cartridge bearings with a through axle?

There are two ways, depending on the type of the hub. Most hubs use a separate axle around the thru-axle. So for example if you have a 15mm thru axle in the front, you would have a 18mm axle around ...
juhist's user avatar
  • 19.4k
8 votes

Is this a sign for bearing maintenance?

I had a similar situation a few months ago. Any time it rained or the bike got wet, there ended up with brown rusty smears running out of the bottom of the headset. Mine uses a semi-integrated headset,...
Tom Carpenter's user avatar
8 votes

Alternative to Shimano TL-PD40 Pedal Tool?

It is possible to remove it using vice grips or slip joint pliers, but I wouldn’t recommend planning to do that over and over. The plastic will get chewed up very quickly. As a last resort, sure, but ...
MaplePanda's user avatar
  • 15.7k
7 votes
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When to replace FS bearings?

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 ...
zenbike's user avatar
  • 29.8k
7 votes
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When overhauling bottom bracket bearings, is it possible to replace loose bearings with cartridge bearings?

Can you clarify if you mean a cup and cone housing, to change from loose bearings to bearings in a metal retaining cage? Like this: ANSWER 1 These can totally be used instead of loose bearings. ...
Criggie's user avatar
  • 126k
7 votes

Why are bearing ball sizes measured in imperial units?

My father worked at Fafnir Bearings for 35 years and even though it ceased to exist as an independent company about 50 years ago, the trademark is still active. In the post World War 2 era, Japan ...
Stanley Pawlukiewicz's user avatar
7 votes
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I can't extract sealed bearings out of hub

I haven't done this one in particular, but here are some things that may be applicable: The spacer between the two bearings may be a tubular spacer that with the axle out is simply held in place by ...
Nathan Knutson's user avatar

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