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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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27 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. ...
3
votes
1answer
92 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
103 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
52 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
89 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
89 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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0answers
33 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
39 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
74 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
89 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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0answers
74 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
182 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
78 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
346 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
1k 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
42 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
101 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 ...
3
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2answers
93 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
84 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 ...
3
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2answers
161 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
354 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 ...
3
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2answers
155 views

Creaking pressfit bottom bracket

From the questions here and a lot of opinions elsewhere, it seems that press fit bottom brackets are bound to be creaking, almost by design, due to low tolerances and how they're installed. It seems ...
6
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2answers
231 views

Toothed plastic cup on bottom bracket got sheared off - still removable?

I messed up. I wanted to switch out the bottom bracket on my bike. When I tried to do that the toothed cup on the left side (non-chain side) sheared off. The entire thing is now plain with its housing....
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2answers
212 views

Minimum space between square taper crank and bottom bracket

I upgraded to a new square taper crankset on a single-speed drivetrain and now the gap between my crank and the bottom bracket is bigger. That's because the cranks taper shape is different from the ...
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2answers
131 views

Regreasing pressfit bottom bracket

I strongly suspect there's creaking coming from my pressfit BB on a road bike. What I don't know is whether the pressfit BBs is reuseable, so once I remove and regrease the whole thing in there, can ...
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1answer
62 views

Scott Addict R2 2008 crankset replacement

I want to replace crankset on my Scott Addict R2 2008. Current crankset is Dura Ace 7800. If I looked correctly then currently I am using BB SM-BB71-41. New crankset will use BB386EVO. Which BB do I ...
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3answers
447 views

Bottom bracket maintenance - is it a thing?

Previously when I've had annoying noises from my bottom bracket I've simply discarded it and bought a (cheap) new one. But the last time I replaced it I got a great offer and splashed out a little ...
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2answers
589 views

Ideal distance between chainring and chain stay

I am building a single speed bicycle, and I have most of the drivetrain parts: Rear hub 18T rear cog (40-40.5mm ideal rear chainline -- wheel undished) 1/8" chain crankset with 40T chainring I used ...
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3answers
181 views

BB spindle length/chainline for re-used Shimano FC-M391 chainset

I'm trying to rebuild an old Univega MTB. Primary goal is to build a good or decent bike from used parts. The crankset+bb that was on the bike when I got it was really worn out. I unscrewed it and ...
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2answers
134 views

Home made bottom bracket plastic sleeve

I want to make a plastic sleeve from a water bottle, for a classic cup and cone bottom bracket, to protect against moisture and impurities that may run down the seat tube. How do I know the proper ...
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2answers
208 views

Loose thread (stripped) tapered bottom bracket frame connection

The threads in the MTB frame that is supposed to hold the bottom bracket lock rings were very loose and it can't hold the bottom bracket in place. The previous bike owner tried to apply Teflon tape in ...
3
votes
1answer
87 views

Self extracting crank preload

This question got me wondering about self-extracting cranks: What bottom brackets are compatible with Miche Evo Max cranksets (self-extracting type)? Where I've seen them on cartridge bottom brackets,...
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2answers
139 views

Surly Pugsley bottom bracket replacement

Does the bottom bracket on Surly Pugsley need to be replaced with a like for like surly part (100mm external bottom bracket) or will any 100mm external bottom bracket be compatible..? The surly part ...
4
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1answer
133 views

What are the metal shavings in my bottom bracket from?

I opened up my FSA BB30 bottom bracket to find metal shavings all around. I opened up the bracket to try to find the source of a creaking sound, I’m guessing this is it - but I’m not quite sure what ...
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1answer
1k views

What is the difference between Shimano BB71 and BB72 bottom brackets?

I often see the Shimano BB71 and BB72 press fit bottom brackets listed on stores alongside one another, like here for example, so what's the difference? Are they both the same geometrically? Is one a ...
3
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2answers
552 views

Wrench to be used with a bottom bracket tool?

It looks like a wrench with a cup at the endpoint. I was wondering what is this tool called and whether it's meant to be used by itself or in combination with a bottom bracket tool, like the PT BBT-22,...
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1answer
147 views

Remove chain guard from bottom bracket

What tool do I need to remove the black plastic cup that is holding the metal holder for my chain guard? I can rotate the metal part but the cup is not moving. While googling I could not find anyone ...
2
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1answer
468 views

Using spacers on crank spindle instead of bottom bracket when fitting HollowTech MTB crank to road bb

HollowTech road BB is 68 mm wide and fits a road crank without spacers. Hollow tech mountain BB uses up to 3 x 2.5 mm spacers. Hence crank is designed to be used with 75.5 mm wide bottom bracket ...
3
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1answer
216 views

Unusual bottom bracket shell

I broke my bottom bracket axle a few days ago, and when I removed the crankarms I discovered my old bike is using a cup and cone bottom bracket but more importantly the bracket shell is a bit odd. It ...
5
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1answer
183 views

The bolt of my pedal's crank arm broke, what could be the causes?

It broke while as I started pedaling when a redlight turned green. In the pics it is possible to see that basically the metal broke! Was it just a poorly constructed product or are there some common ...
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1answer
53 views

What tool do I need to press fit a “Spanish” bottom bracket?

I bought a BMX style bottom bracket called a "Spanish" bottom bracket for a dirt jumper. Instead of using a hammer and a block of wood, I would like to do it correctly with a press... however, I'm ...
3
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2answers
514 views

Which removal tool do I need for this 16t bottom bracket?

The bottom bracket that you see in the picture has a strange 16 teeth profile (3-1-3-1-...). I had this bike built a few years ago and I don't remember what model the BB is. I wonder what removal ...
2
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1answer
52 views

Press fit bottom bracket causing bearings to bind

I have a carbon Cannondale mountain bike with what appears to be a PF30 or PF30A bottom bracket: two 6806 bearings pressed into cups, which are pressed in turn into the frame. With the bearings and ...
4
votes
1answer
150 views

What is this bottom bracket

We were doing a volunteer bike repair clinic and came upon this bottom bracket that I've never seen before. It was on a trials bike and the crankset was destroyed but we couldn't find any way to ...
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4answers
700 views

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

I have a 2 frames with FAG bottom brackets (can't tell the exact model from the outside, but something like this): (datasheet here) in various states of destruction Bike 1 I didn't have the tool so ...
1
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1answer
142 views

Building a Dirt Jump Bike - Spanish Bottom Bracket?

I'm putting together a Deity Cryptkeeper and confused about which bottom bracket to buy... The specs say: spanish 73mm Bottom Bracket Does this mean 73mm wide and 37mm diameter bearing?
3
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2answers
117 views

What is causing this sound?

https://vimeo.com/270962821?utm_source=email&utm_medium=vimeo-cliptranscode-201504&utm_campaign=28749 Guys at the bike shop recommended a bottom bracket change would fix the problem however ...
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1answer
90 views

2003 Klein Attitude comp bottom bracket change type

I have a 2003 Klein Attitude Comp, and I want to put a crankset I have on it. However, the crankset is square taper and the current bb is not. Does anyone know what size square taper bb can go in ...
3
votes
1answer
255 views

Can not replace Shimano Octalink with 105 Crankset

Hello! I am trying to upgrade my bike’s Octalink BB 118 mm to a 105 5600 BB and crankset. The problem is I can not make the plastic pin of 105 left leg fit the hole. I think the axle is too short or ...
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2answers
192 views

Bottom bracket conversion with rare cups

I'm asking this question as I'm interested in the community opinion in the idea of "am I taking the right path" or "is there a better way". tl;drl; - scroll to the bottom, please. Namely, almost ...