Bicycles Stack Exchange
Bicycles Stack Exchange

Questions tagged [bottom-bracket]

The part of your bike that contains the axis the cranks arms spin 'round. (The crank arms are where the pedals attach.)

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

I have a square taper bottom bracket. How can I tell whether it is a J.I.S. or ISO taper with a minimum amount of disassembly? FWIW, it's a Ritchey from 2004. However, it would be nice to get answers that apply to other brands as well.
Reid
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Information regarding UN300 and UN100 (new Shimano Bottom Brackets)

I was about to order a new square tapered BB for some folding bike. Normally I would opt for Shimano UN55, since they tend to last a long time. However I noticed that some new variants were offered: UN300 and UN100. Since I could not find any…
Steffen Villadsen
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Replace old square taper bottom bracket / ISO or JIS?

I'm trying to replace an old worn out square taper bottom bracket from a Peugeot road bike from ca 1985. It uses english threads and the axis is 123 mm. So far so good. But I cannot understand what type of taper (do I say it like that?) I have? It…
Ola
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Bottom Bracket terminology - English BB, SM-BBR60 BSA, English 68mm, ISO/English & BB30 confusion

My head is spinning with confusion on BB terminology, I'm hoping somebody can clarify things. I'm interested in building a road bike with the Dengfu FM098 frame and an Ultegra groupset that I would like to purchase from Chain Reaction Cycles. The…
cdahms
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6
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Determining bottom bracket type

I'm fixing up an old bike I bought in Belgium. Not sure about the exact brand/year. The bottom bracket axle is branded "Flandria". It's a cottered axle. I want to replace this with a square taper bottom bracket. Details of my current bottom…
jvermeulen
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2 answers

How to solve issue with self-unscrewing Praxis Convo BB for Shimano?

I am looking to solve the issue with Praxis Convo BB which unscrews by itself during the ride. What would be the best solution? On my second ride on a Specialized Venge Pro 2019, I noticed that my Praxis "SHIMANO-BB30/PF30 CONV BB 68MM" bottom…
Serg Melikyan
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What are the advantages/disadvantages of press fit bottom brackets compared with threaded?

Many standards for bottom brackets have been gaining popularity recently such as BB30 and PF30. What are the benefits of these press fit systems over the threaded system that has prevailed for decades? Any drawbacks to be aware of?
Sean
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5
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3 answers

Bottom bracket not centered in BB shell

I removed my bottom bracket because there was creaking sound while I was pedaling. Cleaned it and wanted to reinstall but the crank in the middle was hardly turning when I fully tightened the cups on both end. Removed it again saw it wasn't…
Ender
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What is this type of bottom bracket and is it serviceable?

I encountered an old and beat up bike today with the bottom bracket pictured below. I could feel play in the bearings but did not see any lock ring or adjustable cup. The 14 mm bolt of each crank arm was tight. Non-drive…
olliebulle
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5
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Cutting down cartridge bottom bracket left cup

I have a Tange 68x103 mm bottom bracket (pictured) that I plan to use in an old steel frame (building a single-speed/fixed). It turns out that my non-drive-side bottom bracket shell threads were a bit destroyed. My LBS was able to chase/tap quite a…
fideli
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5
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Bottom bracket sleeve is not fixed

I gave my bike to the mechanic a few weeks ago since I have had some problems with my Token bottom bracket. He mounted a new Rotor BBright 4624L on my bike. Coming back from a gravel ride yesterday I heard that there is sand in the bottom bracket…
ruedi
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Threadlocker and Bottom Brackets

The main threadlocker brand available in the US describes its red compound as "permanent" and requiring heat (> 550°F) to free up, and its blue compound as medium strength and requiring only hand tools to free up. I am seeing a lot of photos of…
mrblint
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Is a BB spindle sleeve required?

So yesterday I washed my bike which is a Stock Components Surly Straggler 2015. I noted some squeaking around the BB even after lubing the chain so I decided to clean the bottom bracket. I didn't have the tools so I went out to buy them, and…
zedoo
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Can a bike with an internal bottom bracket be retrofitted to have an external bottom bracket?

External bottom brackets have been appearing on higher-end bikes in the last few years. Can older bikes with bottom bracket shells that come stock with square taper internal ISO 68mm or oversized ISO 73mm bottom brackets be retrofitted with…
raabidfun
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5
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How to select bottom bracket spindle width?

I'm trying to rebuild a bike that I got given free of charge. The bike had no bottom bracket in when it was given to me. How do can I select the optimal spindle width please? I know it's 68mm shell. Edit: I don't have a local bike shop nearby so I…
TechnicallyTroubled
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