22 votes

Drive side part of bottom bracket is impossible to remove and has destroyed tool fitting

Unless your frame is Italian, or a handful of unlikely other makes, your bottom bracket is left-threaded on the drive side. https://www.parktool.com/blog/repair-help/bottom-bracket-removal-...
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  • 11.7k
18 votes
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Should square taper cranks be greased before installation?

I started getting seriously into bike work circa 2002 and was lucky enough to come across Jobst Brandt's view of the topic around that time. Since then, most of which time I've spent working as a ...
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17 votes
Accepted

Difference between Road/Mountain Hollowtech II Bottom Brackets?

I'm going to limit this answer to Shimano Hollowtech II BBs as per the question. Some other brands do it a little differently. Mountain external bearing crank spindles are longer than road spindles, ...
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16 votes

Noticeable clicking from crankset or bottom bracket

There are multiple components that can contribute to a clicking or grinding sound in your drive train in addition to the bottom bracket, including the chain, the pedals, the derailleur and the rear ...
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  • 15.9k
15 votes

How can I remove the stripped plastic cups of a bottom bracket?

FAG bottom brackets (BB) with plastic mounting rings are very common in Germany. The cartridge bottom bracket is really good and resilient, however the polyamide (PA) mounting rings are horrible. As ...
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  • 8,962
15 votes
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What type of crank fitting is this?

The bottom bracket spindle is for cottered crank. The bottom bracket looks like threaded one, so it is likely that it can be replaced with square taper or external cup bottom bracket. To tell which ...
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  • 19.4k
15 votes
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Broken bottom bracket?

The bottom bracket is not damaged, the left hand crank arm is. You have a 'two piece' crank where the right side crank is permanently attached to a steel axle, and the left hand crank clamps onto the ...
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12 votes

How can I tell the difference between a J.I.S. and ISO square taper bottom bracket?

The width across the narrowest part of the flats (end of spindle): JIS = 12.65mm ISO = 12.33mm Use calipers.
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11 votes

Noticeable clicking from crankset or bottom bracket

The clicking, only under load and always at the same point of the stroke, can be due to: A bad pedal. I've had this a couple of times. The crank arm slipping on the crank. Generally if you've been ...
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11 votes
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Replace old square taper bottom bracket / ISO or JIS?

First, very nice drawings and measurements. This makes answering easy. According to the Sheldon Brown link, for JIS "The standard width across the flats at the end of the axle is 12.65 mm", which is ...
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  • 19.4k
11 votes

Pedals turn but bike doesn't move

Judging from your videos, it appears that the chainrings and crank are no longer connected. It appears that you have something called a one-piece crankset. If you are confident that you can learn how ...
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  • 10.8k
11 votes
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Are the chainrings supposed to have irregular sized teeth?

Yes, modern chainrings have teeth that vary from each other. They are formed that way to enhance shifting between the different chainrings. Older chainrings from a couple of decades ago had teeth ...
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  • 1,587
10 votes
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Crank fell off square taper BB. Should I replace bottom bracket

Without seeing any pictures, I think you'll likely want to replace both, but you can figure it out easily enough. Usually, the bottom bracket will be fine after a crank improperly coming loose. The ...
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  • 11.7k
10 votes
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Struggling with bottom bracket installation

Threadless cartridge BBs have their place, and that place is where the threads are destroyed. Thankfully you're not there yet. They are a compromise because they tend to have creak issues sooner or ...
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10 votes
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What type of bottom bracket does my bike have?

There's nothing integrated there - instead, there is one cup still in the frame, and it has been painted red at some point. You'll need either a careful hand with a large spanner to remove it, or to ...
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  • 99.1k
9 votes

What are the advantages/disadvantages of press fit bottom brackets compared with threaded?

Advantages: It's cheaper to manufacture cups, even with fine surface finish and reasonable tolerances than threaded shells. Especially with carbon frames there was an issue with inserting threaded ...
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  • 1,334
9 votes

What is the purpose of greasing BB threads?

To prevent galvanic corrosion. When grease is appied, there is a thin film of grease that prevent direct contact between two different metal. To prevent water and contaminants, especially salt in the ...
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  • 3,461
9 votes
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Are the Truvativ powerspline BBs reliable?

The TruVative power spline BB is a decent, if inexpensive design, and is unlikely to have failed through a design fault. All bikes, regardless of price or quality level, require periodic maintenance....
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  • 29.3k
9 votes

Disassembling crank on a 2006 Trek Pilot 2.1

I had this exact issue come up at work today, with the same crank. It was quite frustrating! Unlike the OP, I tried progressively harder hammer smacks early on. And also unlike the OP, I was unable ...
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9 votes
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Bottom bracket too tight to screw in by hand

If one side screws in without problems, and you've verified the thread orientation, then it's not a compatibility problem. ( http://sheldonbrown.com/bbsize.html - scroll down to "bottom bracket ...
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9 votes
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The bolt of my pedal's crank arm broke, what could be the causes?

The "bolt" that broke is not a part of the crank. Your bike has a so-called square-taper bottom bracket and one side of the axle broke off. This axle is a solid metal part that runs from one crank arm ...
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  • 378
9 votes
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Ideal distance between chainring and chain stay

4mm at the closest point is about the safe spot. 3mm is about the sane bare minimum you can go to if you want to push things. Less is asking for trouble. Note that frames, cranks, rings, and spindles ...
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9 votes

What crank arm bolt is required here?

On the Sora R3000 (and many modern cranksets) the axle, right hand crank arm and chainring spider are all one piece. The left hand crank arm fits on the splines on the axle, and is held in place by ...
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9 votes

Why were press fit bottom brackets invented?

Carbon is the dominant frame material in performance bicycles. You can't thread carbon. There are two ways to get bottom bracket cups into a carbon frame: bond (industrial-strength glue) an alloy ...
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  • 19.4k
9 votes

Drive side part of bottom bracket is impossible to remove and has destroyed tool fitting

The drive side was probably installed without anti-seize/grease, and has corroded to the frame. Presumably you want to save the frame and replace the cartridge. Starting with oils is a good first ...
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  • 99.1k
9 votes
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I replaced my bottom bracket and now my crank arm bottoms out on the square shaft before it can be torqued. What did I do wrong?

Of note is that the amount of gap you have before the chainring bottoms out on the old cup is itself unusually close. That's fine if it works, but it helps to explain what's going on here. There is ...
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9 votes
Accepted

How should I remove this crankset?

The issue seems to be that what is considered "universal" changes over time. The OP seems to have a crank puller that is universal for square-taper bottom brackets. The photo looks like a ...
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  • 2,433
9 votes

Searching for a Pressfit BB replacement for my road bike

You've got a BB386 shell and Shimano road cranks, which are all 24mm. There are a lot of individual replacement bottom bracket models that could do what you need here. The expensive ones are often ...
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8 votes
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Noticeable clicking from crankset or bottom bracket

I've had a similar clicking experience. Not really varying under different load, nor at a certain position of crank arms. Everyone I asked said to me it was the ball bearings in the bottom bracket. I ...
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  • 291
8 votes

Bottom Bracket Lube?

I would avoid doing this. If the Teflon lube has any kind of solvent in it (which it probably does to carry the Teflon), it will break down the grease in the bottom bracket. Eventually, the grease ...
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  • 81

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