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.)

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2answers
348 views

Upgrading a crank set

I presently have a 3x7 speed crankset with a sealed cartridge bottom bracket on my touring bike and want to upgrade to a new Hollowtech II bottom bracket and crankset, specifically, the SHIMANO Claris ...
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2answers
3k views

Broken bottom bracket?

I bought a Trek FX Series 7.5 in April 2017 and ride every day for about an hour. Two weeks ago the crank arms suddenly gave around the bottom bracket and no longer stayed 180 degrees to eachother. I "...
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3answers
293 views

Can a Mamachari be fitted with an 11 speed 52-36T crankset and FD?

I would like to upgrade this bike with a better and faster crankset, 52-36T, but I'm confused if my planned setup will be compatible with the bike I have. I have consulted in our local bike shop and ...
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0answers
140 views

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 ...
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1answer
78 views

Front derailleur will not sit properly on large cog without chain rub

I bought a Vilano Commuter bike ( 3x7 speed ) a while back and recently upgraded the front derailleur, crankset, brifters, pedals and rear derailleur to tourney A070 components. However, I can't seem ...
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1answer
158 views

What is this crank and BB on this bike? And how do I take that sort of crank off?

I have a 2009 Cannondale Six Carbon 3, which supposedly has a BB30 bottom bracket and a FSA Gossamer non-BB30 crank set. It looks like this: I'm having some creaks when I pedal and I'm trying to ...
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1answer
505 views

1991 (I think) Trek 850 MTB bottom bracket replacement. Maybe similar to 830?

I have a Trek 850 MTB that needs the bottom bracket replaced. Is there a standard size to order? If I take off the bike will there be a number that will help me order a new one or do I measure somehow?...
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1answer
855 views

Shimano LP25 Sealed Cartridge Bottom Bracket

I recently attempted to rebuild a sealed cartridge Shimano LP25 bottom bracket. These are meant to be replaced when worn out, but I thought: if someone on YouTube can do it, I can too. The problem is ...
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2answers
303 views

Not able to get crank bolt into bottom bracket spindle

I recently posted a question about changing my chainset, I was advised on this SRAM chainset which I could use which would fit my square tapered bottom bracket. I have attempted to fit the new ...
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3answers
4k views

How to remove hex crank bolt

I have been looking online for tutorials on replacing a chainring (or three) for my Scott mountain bike: https://www.thebikelist.co.uk/scott/aspect-40-2012 When trying to take off the chainset so ...
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3answers
815 views

How do I remove this style of bottom bracket?

I am attempting to remove and replace the bottom bracket from a cheapish 1970s American department store road bike. I've gotten the lockring off, and now the non-drive side looks like this: [Whoops, ...
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3answers
167 views

Bottom bracket sizing

I have a square taper BB which has started squeaking. When I took it out to see what size I have, when I was putting it back in I noticed that when I tighten it to a level which to me felt reasonable,...
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2answers
372 views

Worn out square taper bottom bracket spindle?

I got an used bike with a worn out left crank arm. I tried replacing with a new square taper crank arm and torqued it to 40nm; however, it started creaking soon after and the bolt had become loose (I ...
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1answer
184 views

Single chainring conversion issues

I've got a Specialized Crosstrail Elite. I want to get rid of the front derailleur and go for a single front chainring. Its a 68mm BB shell but needs a 73mm BB with spacers. It currently has a FSA ...
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1answer
785 views

Shimano Front Chainwheel FC-MC19 Replacement?

I have Shimano FC-MC19 22/32/42 175mm crankset on my MTB for 17 years and it's time to replace it but I find it difficult to figure out what new crankset will fit my bicycle. Two years ago I replaced ...
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4answers
1k views

Pitted Cups - Can I get away with this level of pitting?

I have two bottom bracket cups that I'd prefer to reuse (finding Avocet Bottom Bracket cups even on Ebay is hard!). I have purchased a replacement Avocet spindle of the correct size. I'm wondering if ...
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1answer
106 views

Octalink v2 bottom bracket on italian shell

I'm re-building an old Italian Bottecchia mountain bike which has Italian BB shell (70mm) and the previous bottom bracket was a square taper with 130mm spindle (measurement confirmed via calipers.) I ...
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4answers
4k views

Can I grease a crank spindle/bracket without disassembling the crank set?

A bit of history: the grooves on the spindle are partially destroyed/skewed by cycling with a loose crank, so I applied a lot of force to a hexdriver to get the crank arm on. Now, it would be quite ...
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2answers
113 views

What is this bottom bracket standard called

I am looking to buy a cheapish power meter.I Would like to see if am improving at all. I want to know my bottom bracket standard and if I can fit a bottom bracket power meter?
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3answers
2k views

How to install press fit bottom bracket into new frame

I bought a new carbon frame, which came with a press fit bottom bracket. All of the resources I can find for the installation of these includes information about how to remove the old bottom bracket, ...
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1answer
686 views

Use 105 crankset on 9x2 Sora equipped bike

Want to ditch my basic square taper FSA Vero (50/34) crankset on 9x2 speed Sora drivetrain (2018 Devinci Silverstone 2) in favor of 105 compact crankset. I will attempt to get one in 50/34 not to mess ...
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1answer
272 views

Bottom Bracket for Trek Crossrip Elite 2014?

I am planning to upgrade my group set to 11 speed 105 along with the bottom bracket. However, I have no idea what type of BB should I get and brand. If anyone could help me that would be great?
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2answers
483 views

Strategy for removing a bottom bracket with plastic retainers?

Bottom brackets that have plastic retainers have a reputation for being problematic to remove. Often the tool interface on the plastic retaining ring will shear off if the plastic is old or the bottom ...
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1answer
644 views

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 ...
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2answers
313 views

What crank arm bolt is required here?

The crank arm on my Decathlon Triban 520 became loose during a cycle. On inspection the crank arm bolt is missing. What bolt do I need as a replacement? (Or how can I figure it out?) The manufacturer ...
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3answers
106 views

how do i put my bottom bracket back together

I was bloody relived I could get the bb apart that I just rushed ahead and fogot to take note of how it came apart.DOH!! I now have the following dilemas 1)What size bearings were they again(dont ...
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1answer
254 views

Is ISIS compatible with BSA?

I want to get a Cyclone motor to install into my bike. My bike has a 120mm BSA bottom bracket, and the motor is available in Square Tape and ISIS varieties. Are these compatible?
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2answers
858 views

Is the Shimano UN55 bottom bracket in 68x122.5 and 68x127.5 sizes JIS square taper?

On one online sales site there's a drop-down widget showing various sizes of the Shimano UN55. "JIS spindle" appears as a bullet-point next to someone of the size choices but not all of them, hence ...
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1answer
2k views

How to remove stuck Shimano Hollow-Tech bottom bracket cups?

When I tried to remove the bottom bracket bearing cups using the BB tool it was very hard to move or it's just stuck. Tried WD40 then slowly tapping the tool using a mallet didn't work. To cut the ...
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1answer
137 views

What bottom bracket do I have

What type of bottom bracket do I have? I'm looking for a video on how to service my bottom bracket but I'm not sure what type I have. I have a Cannondale CAAD8 from 2011 with a Shimano 105 groupset. ...
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1answer
1k views

JIS and ISO square taper

I've read Sheldon Brown's page on JIS and ISO and have read exchanges in forums about the pros and cons of using ISO cranks on JIS bottom brackets. If my understanding is correct, these standards ...
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2answers
156 views

Loud “thunk” sound each time my shoes pass the 1 o'clock position with both shoes

Folks, I need a hand. Does anyone know of a bike mechanic that can diagnose problems via FaceTime or another audio/video app? I ride strictly indoors (I’m in Iraq) and there’s a knocking coming from ...
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1answer
1k views

Stripped out bottom bracket

The bottom bracket of my bike was completely stripped to the point that when you push the left side crank arm, the right crank moves and you can see the bottom bracket lock move out the frame. The ...
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1answer
10k views

Is it possible to convert a press fit bottom bracket to threaded?

I have a road bike with a press fit bottom bracket (I'm not quite sure which kind). The guides I have watched make it seem fairly risky to replace and requires ~$250 worth of tools to replace. I saw ...
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2answers
176 views

What tool do I need to remove this bottom bracket?

Would I need a three-notched tool to remove this?
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2answers
349 views

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 ...
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1answer
390 views

Threading for BB (British) for Hollowtech 2 or square taper crankset?

I have square taper crankset from Sugino (compact double 48-34). I am using their aluminium cartridge BB (I think it's 68mm). Anyway, I was wondering what is the difference, if any, regarding the ...
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1answer
263 views

Bottom bracket spacers

I'm installing a Sram GXP English-threaded bearing set in my 68mm bottom bracket. It is replacing a Shimano Ultegra-level HollowTech II bearing set. The crank set I'm installing is a Sram XX 42/28, ...
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2answers
337 views

Square taper spindle won't fit into the bottom bracket

I'm making a road bike with random components I have in my garage. Everything works ok except for the bottom bracket which is a square taper 115mm long and it is still spinning free even if I turn the ...
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1answer
954 views

Which way does this ring go on the left crank of this Shimano deore hollow tech external bottom bracket crank?

On the inside of the left crank there is a small ring. The picture shows where the ring is meant to go. The ring is smooth / flat on one side. The picture shows the flat side which seems to have been ...
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2answers
2k views

Last ditch attempt to fix creaking bottom bracket (Epoxying the BB into the frame)

I have a Canyon Ultimate CF SL which has the all to common press fit bottom bracket creak. I use 24mm Shimano Chainset and have tried the official Shimano Ultegra BB86 and 92 Bottom Brackets, a ...
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1answer
148 views

Bottom bracket replacement bearing

I have been looking for a press-fit bottom bracket replacement bearing for a Giant Fastroad SLR1 (2016 model). The markings on it identify it as an FSA 19mm diameter, that is the spindle is 19 mm I ...
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2answers
4k views

Can you get a threaded bb30?

I've a threaded shell, but i have got bb30 cranks, can you get threaded bb30 bottom brackets that the it can with fit the bb30 cranks?
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2answers
2k views

What type of crank fitting is this?

I have an old road bike I want to get a single speed crank for but don't know what fitting the bottom bracket has.
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1answer
281 views

Wilier Zero9 bottom bracket

Im trying to investigate what type of bottom bracket has by Wilier Zero9 road bike. Looks like some pressfit but Im Not sure, inner bearing width has 25mm. I have Shimano Ultegra 2x11 6800.
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2answers
199 views

Old Sears Simpson bike bottom bracket replacement

Got the pedals out, but I'm struggling with both cups. I don't know which way the threading goes either. The bike was made in Poland, pretty old. Anyone know what I could do? I have a flat-shaped ...
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2answers
792 views

Quarq Dfour Fit Problem

I recently buy my first Quarq Dfour power meter to replace my crank Shimano Ultegra 6800. but I have the problem that the quarq spindle its too short ( 106 mm quarq vs 109 mm shimano ultra ). I don't ...
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3answers
464 views

Bottom bracket replacement

I have an old '89 Trek Singletrack 950 with the original Shimano Mountain LX group bottom bracket. I'd like to replace the bottom bracket with something new. Can anyone help me determine what will fit ...
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2answers
2k views

Damage to bearings from press fit bb removal?

Is it possible to remove the bearings from one bike's bb and put them on to another or would using a tool such as the Park tool bbt 90.3 damage them somehow?
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5answers
1k views

Is there any reason for the rear frame and bottom bracket to be asymmetric?

I just received a new non-brand carbon frame and immediately noticed that the bottom bracket looks to stick out significantly more to one side than the other, and the rear bottom forks also seem to be ...

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