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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3k 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
750 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
556 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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1answer
808 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
121 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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3answers
287 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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3answers
2k 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
942 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
156 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
138 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
743 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
1k 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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3answers
91 views

Bottom bracket creaking only when pedaling hard.

When pedaling with a decent amount of force a very loud creaking sound can be heard coming from the bottom bracket area (it is very loud when standing on the pedals). It makes a creaking noise on each ...
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1answer
145 views

What bottom bracket do I need for a decathlon rockrider 5.0

The bottom bracket on my Rockrider 5.0 has a little too much play in it so I figured it best to change it before I get a failure whilst I'm commuting. Does anyone know which bottom bracket I would ...
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1answer
212 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
60 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
41 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
1k 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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1answer
635 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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2answers
320 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
129 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
254 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
485 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
137 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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2answers
3k 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
389 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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0answers
51 views

Purefix Kieren Pro

TL;DR FRAME: Kieren Pro (68mm BB) Which BB is suitable for this frame? (want to use SRAM s100 crank) If BB must be Truativ 108 or 113mm, how do adjust chainline? Thanks for your time and efforts ...
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2answers
93 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
381 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
557 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? ...
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1answer
69 views

Niner Biocnetric Compatibility

Have an older Niner Air 9 Carbon that has the original Biocentric eccentric hub. Does anyone know if the Biocentric II is compatible?
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2answers
577 views

FSA Omega MegaEXO Press fit BB 19mm removal (non standard BB86)

Has anyone removed a 19mm spindle (Omega) Press fit bottom bracket without destroying it in the process? I have watched http://www.fullspeedahead.tv/video/7006668/installation-of-megaexo-crankset-on ...
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2answers
159 views

How does pedaling power transfer to the bearings in Hollowtech II bottom bracket?

I just installed a Shimano Hollowtech II crank and bottom bracket on my bike, and I'm wondering how they work together. My understanding is that the bearings are located in little cups that screw ...
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1answer
140 views

Frame not faced for BB. Strip the paint or leave as-is? [duplicate]

So I just got my new frame from the LBS. They were supposed to face the frame, but only faced the head tube (hopefully, can't check it since the headset is already installed.). Sadly, they didn't ...