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
138 views

BB Lockring won't completely tighten

I am trying to put the lockring back on my BB after adjusting it to reduce the play, but I am unable to full tighten it. I can hand tighten the lockring, but as soon as I try to use my hook spanner to ...
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1answer
70 views

How do I remove a bottom bracket?

I have managed to remove the threaded locking mechanism of this bottom bracket. However, I can't get the bracket out. I have tried to just bang it out, but it doesn't move. I don't know what else to ...
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1answer
749 views

How tight should a threaded BB be?

I have an english-thread, octalink Shimano bottom bracket, and a new frame. The frame has been faced before painting. I am not sure the BB is compatible with the frame. When trying to install the ...
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1answer
217 views

How can I use a small Shimano BB on any frame?

I have a Shimano BB-ES25 bottom bracket and 45T crankset that was removed from a Giant-CRX City with an eccentric hub (it had Shimano Alfine internal hub gears). They have literally never been used, ...
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2answers
751 views

Koga touring bicycle bottom bracket loose, does it need replacing?

I have a 2009 Koga Signature high-end touring bicycle (internal hub gear, hub generator, half-open chainguard, ...). I'm cycling around 100 km/week (8½ km one-way commute) plus trips, so I've probably ...
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2answers
965 views

Cartridge equivalent spindle length for Shimano BB-6207 116 mm Cup and Cone Bottom Bracket?

I'm building up an old Terry bike and will likely pick up a NOS Shimano 600EX FC-6207 crankset. The corresponding bottom bracket for this crankset is the 116 mm BB-6207 cup and cone. However, given ...
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2answers
1k views

How to upgrade a dust cap?

For all you mechanics out there I am sure you hate these things. Dust caps are the bane of my existence. They are cheap and bend easily. I want to get a better sturdier one for a bike I am working on. ...
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1answer
51 views

Praxis Bottom Bracket Performance on BB30 Frame

I'm looking at upgrading the crank (stock FSA to Force 22) and getting a Praxis BB for my Cannondale CAAD10 BB30 frame. http://www.praxiscycles.com/product/conv-bb-sramgxp-isis-2/ It seems like ...
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1answer
90 views

Q-factor of external bearing BBs

Seems to me that the Q-factor for an external bearing bottom bracket will be greater than that of an equal size (say, 68mm road bike BB) cartridge bearing. Is that the case?
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1answer
98 views

Are Hollowtech II bottom bracket normal?

I've just installed a brand new Ultegra 6600 crank/bb on my brand new frame. Everything is fine and properly installed, but the crank doesn't rotate as freely as a square taper BB. The bike is not yet ...
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1answer
685 views

Replacing SRAM Red chain set with Ultegra - bottom bracket?

I have a cyclocross bike with an Ultegra 6700 chainset and a road bike with SRAM Red. I'm looking to get a Stages Ultegra power meter (left crank arm mounted) that I can swap between both bikes. This ...
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1answer
595 views

Bottom bracket mysteriously squeaking

Somewhere from the non-drive side of the drivetrain is coming loud squeak when I pedal hard. The story is long. First I threaded the BB-ES25 incorrectly, and had to spend half an hour with a file to ...
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1answer
635 views

Shimano Ultegra Bottom bracket replacement with Dura-Ace

The bottom bracket on my Van Nicholas Astraeus is a creaking when going up hills. It's already been tightened recently, yet seems to creek more and more lately - probably due to the mileage (many, ...
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2answers
320 views

New rocky mountain soul 29 making creaks by the bb

Not to sure what it's coming from I don't have the tools to take the crank off or adjust the bb. The funny thing I don't get is that the creak is gone the next time I ride my bike then when I may go ...
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1answer
220 views

What Bottom Bracket for a 2007 Rush Hour frame?

The stock rush hour bottom bracket is a FSA BB-7420. Would a Shimano BB-UN54 that is 68 X 107mm work in that frame?
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0answers
41 views

Identify my Motobécane racing bike

I bought a Motobécane last year (pics below), and now that the bottom bracket is broken, I really need to know the model of the bike, to help me change that piece. It would also be helpful if someone ...
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1answer
82 views

Why is my electric bike 'clanking' under load?

I have a Giant Esprit Twist Power electric bike, which apart from not having nearly enough words in its name also has a problem related to the crank. When I put a lot of load through the pedals there ...
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0answers
202 views

Serial numbers on bottom of a pedal crank housing from a 50s era Schwinn?

Can someone please explain what these three numbers mean on the pedal crank housing? I believe this to be the pedal crank housing from a 1956 Spitfire Ladies Bike. The Schwinn Serial reads M0D502 ...
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1answer
238 views

bottom bracket Stronglight JP400 equivalents

I need to replace my bottom bracket cartridge because it is knackered. After a bit of reading it seems that there may be many types of cartridge variations (axle lengths, threads, size of square ...
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2answers
3k views

Stationary bike “clicks” when pedaling - crank axle is moving sideways. How can I fix this?

I've got this stationary bike, a York C202, which has developed a problem - namely it "clicks" when pedaling. This is highly annoying, as there's nothing I seem to be able to do about it. I diagnosed ...
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1answer
60 views

Crank fell off square taper BB. Should I replace bottom bracket

After years of use and multiple retightenings my crank will fall off my bike about once a week and definitely needs to be replaced. I believe that the square hole of the crank has expanded to the ...
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2answers
2k views

Lower vs. Taller Bottom Bracket Height

The bottom bracket height on some bikes can be adjusted 7.0mm by flipping a "chip" in the shock mount linkage. This also effects head tube angle by 0.5 degrees. Theoretically speaking, What are the ...
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2answers
107 views

Do I need to chase a thread before installing a bottom bracket on a new frame?

Currently I'm building a new Surly Cross Check, and it needs a 68mm BB (english threaded). Furthermore, I plan to use a cheap $15 shimano BB with JIS square tapered interface, nothing special. Do I ...
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1answer
586 views

Can't get the drive side bottom bracket cup out

I have an older Raleigh frame that I converted to a fixed gear and the bottom bracket cup on the drive side has been painted over a few times and I can't get it out. This is the type of cup (the one ...
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1answer
49 views

Bottom Bracket Press fit to a square taper

I like to use my old Campagnolo crank on a new road bike frame. The frame has already a Pressfit BB71-41A installed. The crank needs a sqaure tape. Is it possible to use the crank with a adapter or do ...
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1answer
146 views

Shimano Hollowtech II bottom bracket: milling the frame necessary?

In a bike shop I recently asked for bottom brackets. The seller said, when choosing a Hollowtech II bottom bracket (like SM-BB70), compared to Octalink/square taper bottom brackets the outer (lateral) ...
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3answers
116 views

Trouble Removing bottom bracket. Is it my Tool?

I'm having trouble removing my bottom bracket. I'm using quite a bit of force as far as I can tell. But neither side is budging. The bike is a 2011, and I've never removed the bottom bracket, but ...
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2answers
497 views

What are my options for replacing a Shimano Hollowtech II BB?

I have had a 'Deore' equipped mountain bike for 3-4 months now. However, there is grinding noise from the area of the cranks and I suspect the bottom bracket. On a local MTB forum I heard that Deore ...
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1answer
57 views

Over-tightening a BB

I just installed an external bottom bracket (Hollowtech II type) on my steel bike. The manufacturer (Sugino) prescribes a 40-50Nm torque. I own no torque wrench, so I just wrenched it on pretty tight. ...
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2answers
125 views

What kind of bottom bracket fixing is this?

Dismantled my bike to try and take a look at the crank bearing, as I fear it may be getting dry. Unfortunately at the stage pictured I could go no further. The outer and inner rings appear to be ...
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1answer
153 views

Which bottom bracket do I need to replace crank on a Trek FX 7.1?

I have a Trek FX 7.1 that I've rode for several years now and replaced parts as they've worn out. Now I'd like to upgrade the whole drive train with Tiagra 2x10 flat bar shifters, derailleurs, crank, ...
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1answer
502 views

BB30 bottom bracket won't stop clicking

My mountain bike has a BB30 bottom bracket that was clicking under power. The bike is only a month old, so I figured, break in period, and I took the crank off and greased everything up with teflon ...
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1answer
738 views

What are the different types of bottom brackets?

Right now I am only familiar with two types of BBs (bottom brackets): The square type on my older mountain bike. The hallowtech (SM-BB70) that comes with a Deore XT crank I bought on my newer bike. ...
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1answer
59 views

Help me understand bottom brackets and cranks

I have a Norco Threshold cyclocross bike (http://www.norco.com/bikes/road/cyclocross/threshold-carbon/threshold-sl-ultegra/) . It has a PF30 bottom bracket and an FSA Energy Cross PF30 46/36T crank. ...
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2answers
28 views

Replacing my bottom bracket. I need help IDing a replacement

So I have owned a Swhinn Network 3.0 (21-speed. Square tapered BB. All aluminum) for almost 5 months, and at about month 3 the bottom bracket started giving me some noise. I work in a bike shop on my ...
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1answer
21 views

Campagnolo 1973 strata cranks(BMX) help

I am installing them on a very rare BMX frame.the bottom bracket shell measures 66mm.I believe I'm looking for a spindle length of approximately 110mm.it also has to have English threads.my question ...
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1answer
110 views

Technical documentation for Shimano FC-M510

I'm having a hard time finding the technical documentation (equivalent of https://www.dropbox.com/s/yx5hq4cezpdz641/alivio-crankset-service.pdf?dl=0) for the Shimano Deore Hollowtech 1 crankset, ...
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1answer
90 views

Exchange FSA K-Force Light chainset with a SRAM RED

I'm the lucky owner of a Fuji SST 1.0 from 2010 (mounted with a Shimano press-fit bottom bracket). I would like to exchange the front chainset from a FSA K-force 53/39 to a SRAM RED 50/34. Can you ...
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1answer
174 views

Triple chainset to single chainset; BB compatability?

I'd like to upgrade the chainset on my GT Avalanche 1.0 2013 so I have no front mech or shifter and just one ring on the front; just 10 gears instead of 30. My current chainset is a Shimano M522 ...
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1answer
319 views

Will this crankset fit my bottom bracket?

I've got a 2004 Trek 4300 that I need to replace the crankset on. I was able to look up the bottom bracket size here and see that it's a 73x122.5. I'd like to buy this crankset but I'm not exactly ...
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1answer
128 views

Soft “Thunk” in the crank

I have a one month old Citizen foldable bike and I have noticed a soft "thunk" when turning the crank. It sounds the same whatever gear I am in. It also seems to go away for a short while if I stop ...
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1answer
232 views

Windsor - The Hour - Bottom Bracket Dimensions

I'm looking to replace the bottom bracket in my Windsor "The Hour" since I'm buying a new crank set for my bike. What are the dimensions for the bottom bracket: both shell width and shaft length? I ...
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2answers
2k views

New frame bottom bracket and crank compatibility and general stupidity!

I recently bought a Scott CR1 SL 2012 frame to replace a crash damaged frame on my 2009 Boardman Team Carbon road bike. The intention being to move as much as possible across from the old bike on to ...
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1answer
342 views

screeching noise in bottom bracket

There is a very loud screeching noise when i pedal hard on the down stroke. Be it moving off or climbing up a hill. It is not coming from the front wheel, which i originally thought came from brake ...
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2answers
58 views

Finding a replacement crankset (and maybe a bb to go with)

I am in need of replacing my crankset on my hybrid discovery 401 - although all that is left of the 401 now is the frame and the bb/crankset. it has a sealed bb 113/68 square taper. I am struggling ...
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1answer
169 views

How to fit BB bearings to install Ultegra Crank on road bike Wilier Cento 1

I've bought a used Wilier Cento 1 carbon road bike frame (not the new Cento1SR, but the previous model). Now I would like to transfer all Ultegra 6700 groupset components from my existing bike to it. ...
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2answers
81 views

Need help identifying bottom bracket

I need some help identifying my bottom bracket. One of the bearings is in a very bad shape and needs to be replaced. Bottom bracket photos
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0answers
175 views

Choosing the correct Bottom Bracket

I have a 2011 Commencal Supreme DHV3 Team edition and I need to replace the bottom bracket. The problem is that I am confused about what the correct model to buy is. The tech book for the bike ...
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1answer
196 views

Loose pedals on Norco MTB

Just replaced my pedals on a very old Norco MTB. I noticed while working on it that the whole peddle structure is wiggling from side to side is this normal ? I took the plastic caps off the base to ...
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1answer
416 views

MegaEXO Omega BB and Hollowtech II crank compatibility?

I have a Giant TCX SLR 2 (2014) with a FSA MegaEXO BB and FSA Omega crankset (46/36). I just purchased a Ultegra 6750 crankset (50/34), can I run it on my existing BB? If not, what BB do I need? ...