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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8
votes
4answers
2k views

Creaking bottom bracket

I have a Trek 3900 Mountain bike that had a serious creaking problem whenever I would pedal. I found that the ring that holds the Shimano sealed bearing was really loose. I tightened it up and it ...
42
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16answers
179k views

Creaking from cranks/spindle. How to fix?

Recently the cranks on my bike started to creak. I checked with my usual "bike-bible" Park Tool. They recommended dis-assemble, lubricate, re-assemble. So I did that. Remove cranks. Remove spindle. ...
11
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2answers
45k views

Difference between Road/Mountain Hollowtech II Bottom Brackets?

Shimano sells Hollowtech II bottom brackets which are labeled for road and mountain bikes explicitly. I had no trouble fitting a Shimano Deore BB52 Hollowtech II Bottom Bracket into my road bike and ...
5
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1answer
3k views

What types of BB-axle to crankarms interfaces are there?

On the lowest end, we have the taper/square interface. I believe it is standard i.e. there are no variations in the sizes. image property of VP Components USA Then there is the octalink. Actually ...
8
votes
3answers
61k views

How do I measure a bottom bracket?

I need to replace the bottom bracket bearing on my fixie. I plan to get a Shimano UN26, but I note that there are a number of different sizes. The sizes seem to be expressed as 68-110, where 68 is the ...
1
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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 ...
18
votes
7answers
41k views

How to remove a crank arm with stripped threads?

A friend called me up yesterday after a mis-adventure during his attempt at a bottom bracket overhaul. He stripped out the threads on the (left) crank arm while using a Park crank puller. In a pinch, ...
19
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5answers
30k views

What are the benefits of external bottom brackets?

Pretty soon, I plan to replace the bottom bracket on my early 90's Sakae Litage road bike. It takes a standard, English-threaded bottom bracket. Right now I think it contains loose bearings--I was ...
8
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5answers
4k 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 ...
12
votes
3answers
21k views

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 ...
8
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6answers
13k views

Riding on a failing bottom bracket - what could possibly go wrong?

My BB is showing the first signs of being on the way out (a click when I drive either foot down hard; if I remove the chain there's a barely perceptible clicky feeling at the same crank position as ...
6
votes
4answers
438 views

Why were press fit bottom brackets invented?

What I've seen online says that it allows for lighter and stiffer cranksets becasue the axle can be a larger diameter. However, FSA sells BSA threaded outboard bearings compatible with BB386 EVO which ...
6
votes
3answers
970 views

Wilier oversize bottom bracket bearing cups for Shimano crank

My bike frame is a Wilier Imperiale with Campagnolo crankset. I am changing the crank to a Shimano 6800. The bottom bracket does not fit to the Shimano one. It is old version WILIER OVERSIZE BOTTOM ...
4
votes
1answer
5k views

Replaced Shimano Bottom Bracket, now front derailleur won't shift to largest gear

OK, so in my quest to get my old Trek 7000 ZX MTB running again after a long retirement, I am having an issue with replacing the bottom bracket. The bike came with a Shimano LP25 that is marked BC 1....
4
votes
2answers
469 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 ...
4
votes
1answer
2k views

Square taper crankset develops play after changing bottom bracket

After replacing a bottom bracket with square taper I repeatedly have to tighten the screws that fix the crankset (on each side) to the bottom bracket axle or otherwise I can feel sometimes a slight ...
2
votes
1answer
806 views

Yet another stuck BB. Help me save my frame!

So I have two bikes and a year ago I went through the challenge of unscrewing a stuck BB. The solution was to put the tool in a vice and twist the frame around it. Today I have an even more difficult ...
2
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3answers
1k views

Failing to unscrew BB - what now?

I have an external bearing BB, that I need replaced (It is quite badly rusted). I opt to do the repair myself. The bike is a Specialized Hardrock, the crank arms are SR Suntour. Having removed the ...
18
votes
8answers
117k views

Noticeable clicking from crankset or bottom bracket

A few days ago I began hearing a clicking noise coming from the crankset and I can also sense a slight hitch when the right crank is at its upmost position just when it's about to go down. The ...
20
votes
4answers
62k views

How do I know when to replace my bottom bracket?

With out completely removing the cranks and bottom bracket, how can I tell when it's time to replace my bottom bracket? The current symptom is a slightly 'rough' feeling when I pedal. It's not ...
1
vote
1answer
183 views

Bottom bracket servicing

My crankset is driving me nuts, because of creaking noises when pedaling. I have fixed the issue twice already, by removing the bottom bracket (FWIW, it's a 68x115mm square, pictured below, and my ...
11
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4answers
1k views

Should square taper cranks be greased before installation?

There’s a fierce debate over whether the interface between a square taper spindle and crankarm should be lubricated or not. Adding to that, everyone seems to have their own take on the issue. Here’s ...
6
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6answers
43k 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 ...
4
votes
1answer
33k views

Why does my non-drive side crank arm come loose?

I tighten the bolt super hard. Ride for a while. Then it comes loose again. I don't know if its my BB or the bolts. How can this be fixed??
4
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3answers
3k views

Cartridge bottom bracket with lockring on one side only

NB There is an edit to this post added 06.02.2017 I need to replace the 68/118 BB on my Giant Rock (made around 2000 I think). It has a locking ring on one side only as shown in the photos. The ...
3
votes
1answer
2k views

Replaced left crank arm but still comes loose?

A few weeks ago I bought a new (albeit cheap) self assembly bike from a local store, this bike to be exact http://tinyurl.com/gw77p9t . After about two weeks use (one and a half hours of cycling on ...
1
vote
1answer
2k 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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2answers
985 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 ...
7
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4answers
15k views

Bottom bracket making noise, should it be fixed now or can I wait until regular maintenance?

My bike has been ridden 4 months / 2000 miles and is no longer completely quiet. About a month ago I noticed a whispering noise like a wire brush sliding across a cymbal. It happens on the power-down-...
7
votes
3answers
1k views

Bottom Bracket Creaking

I have a 1993 Rockhopper frame that I'm riding as a singlespeed. I have some creaking around my bottom bracket. I've just recently stripped and painted the frame, and there wasn't anything ...
6
votes
2answers
2k views

Lost left crank arm crank end cap

What parts do I need to put this back together? I've lost some pieces going for a ride but I'm not sure what exactly. I think I'm missing the end cap to the crank and maybe a spacer. I was heading ...
5
votes
2answers
8k views

Does my bottom bracket need replacing?

About two months ago I bought a Boardman HT Comp. Today I took it into my local bike shop for a service. While I was in the shop one of the technicians had a quick look at it and told me that my ...
5
votes
4answers
1k views

Cruiser bottom bracket is clicking and grinding

My Trek Pure Deluxe 3-speed cruiser has been making a clicking noise when riding for some time. The problem is faint, and is more felt than heard. However, it's been getting worse; it now makes a ...
5
votes
1answer
351 views

Claud Butler Tandem - add a front derailleur?

I'm in the process of stripping a SWB Claud Butler tandem so I can get it repainted. There are a couple of things I need help with.... a) Can you fit a front mech to the bike, and if so, are there ...
4
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2answers
3k views

Replace asymmetrical BB with symmetrical cartridge and spacers?

My bike has a square taper 68mm width cup and cone bottom bracket that is wearing out. I was hoping to replace it with a sealed cartridge (shimano UN55 or similar) but then I found that the spindle ...
4
votes
2answers
175 views

What tool do I need to remove this bottom bracket?

Would I need a three-notched tool to remove this?
4
votes
2answers
6k views

Bottom bracket lockring keeps loosening up

The lockring on the bottom bracket keeps loosening up, it's now ~15-20km. What can I do to prevent it? The steeper the hills I ride the quicker it comes undone - it's a single speed so it's clear and ...
4
votes
3answers
2k views

Clacking noise as right crank goes 'over the top' once per revolution

Every time the right pedal goes over the top I get a single clack noise with a little more 'travel', a point where the bottom bracket moves without any resistance, from that point in the rotation. I ...
3
votes
4answers
3k 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 ...
3
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2answers
5k views

How do I determine bottom bracket size [duplicate]

I got a cheap old bike I fixed up and I want to install a mid drive motor but the ones I found require a specific bottom bracket size and I don't know what size bottom bracket I have. The wheels are ...
3
votes
1answer
199 views

If chain/ BB/ casette are dead can chainrings and derailleurs still be OK?

I bought a brand new bike last May (2015 Brodie Elan) and proceeded to put 11,000km on it by November (cross Canada ride plus some commuting). Around the 11,000km mark I brought it back to the shop ...
3
votes
1answer
271 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?
3
votes
4answers
18k views

Cross threaded/stripped bottom bracket

I installed a new sealed bearing in my bottom bracket. Unfortunately after tightening it most of the way, it jammed and I realised I'd cross threaded it. I then removed it and reinstalled it. It ...
2
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3answers
3k 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 ...
2
votes
3answers
15k 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 affects head tube angle by 0.5 degrees. Theoretically speaking, What are the ...
2
votes
2answers
716 views

What do you call the crankset system type on the Sram Apex?

I see these everywhere, but no one can come up with a consistent name for them from company to company. GXP is the closest I can come to a name for the bottom bracket. http://www.sram.com/sram/road/...
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2answers
1k views

Using Loctite for integrated head set and bottom bracket installation

I'm in the process of building up a new bike from scratch. Since the last time I have done this many things have changed, reading varios forums and watching numberless videos on YouTube have not ...
2
votes
3answers
2k views

Can I replace a GXP press fit bottom bracket with a Hollowtech?

I've recently acquired a frame for a project and have an Ultegra crank set from my crash bike I want to use on it. The frame currently has a GXP 24mm press fit BB and I've got a spare Hollowtech BB,...
2
votes
2answers
4k views

Identifying bottom bracket

First and foremost.. I'm slowly trying to replace my bottom bracket.. it makes a kind of knackered-bearings sound when I move the pedals round without the chain attached. This is because I've been bad ...
2
votes
3answers
1k views

Identifying an eccentric bottom bracket?

I have a bike powered by a Gates belt-drive and a Shimano Alfine 11. It also has an eccentric bottom bracket to adjust the tension on the belt drive, and a SRAM GXP bottom bracket. The other day, ...