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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41
votes
16answers
172k 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. ...
19
votes
6answers
68k views

How often should I grease and repack my hubs and bottom bracket?

I am commuting 7 miles a day (round trip) in all weather in New England (temperate, moderately wet climate, cold winters). Overall I am putting about 1000 miles per year on my commuter bike, a 2009 ...
19
votes
4answers
26k 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 ...
18
votes
4answers
50k 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 ...
16
votes
8answers
74k 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 ...
16
votes
7answers
35k 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, ...
12
votes
3answers
17k 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 ...
11
votes
4answers
13k views

Annoying clicking sound from the bottom bracket

I just purchased a Fuji ACR 2.0 road bike from a guy who bought it three months back but didn't ride it at all. I brought it home and found that it is making a clicking sound when I pedal. The sound ...
10
votes
2answers
2k 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 "...
9
votes
2answers
28k 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 ...
8
votes
1answer
2k views

Replace old square taper bottom bracket / ISO or JIS?

I'm trying to replace an old worn out square taper bottom bracket from a Peugeot road bike from ca 1985. It uses english threads and the axis is 123 mm. So far so good. But I cannot understand what ...
8
votes
5answers
2k views

English vs Italian bottom bracket - chainline considerations

I'm planning a new build and for the first time, I'm working with a frame that requires an Italian bottom bracket. My question isn't specific to the build, but a general question about chainline. ...
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 ...
8
votes
3answers
57k 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 ...
8
votes
3answers
3k views

Chainring rubbing frame after tightening cranks. What should I change?

Bike details: Singlespeed (steel) Square taper threaded BB 58/19 ratio (hence huge chainring rubbing the frame) 130mm bcd 5-bolt crank/chainring Mileage on cranks: several thousand km in all weather (...
7
votes
3answers
3k views

Crank arms are not parallel to each other. What could have caused this?

It is a cottered crank. Crank arms themselves don't seem to be bent. It is a non-cartridge style spindle. Any ideas as to why they are not lining up?
7
votes
4answers
11k 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
2answers
3k views

Bottom bracket too tight to screw in by hand

I'm trying to install a new bottom bracket (BB-UN55, BSA) into a new aluminum frame. Trying to screw them in by hand only allows me to go a few threads deep. On the non-drive side cup there is some ...
7
votes
4answers
513 views

Help needed identifying mystery screws on 1940s tandem

My tandem has two small screws above each bottom bracket, one on each side (so four in total). I've not seen them on any other bike, and I can't figure out what they're for! Suggestions so far have ...
7
votes
4answers
13k views

How to properly clean and lube the bearings on a sram apex bottom bracket (GXP)?

For this bottom bracket type I am not sure you can take the bearings out to lube them. How do I get grease in there. Also how do I get the old grease out? Does it even matter? I found this video (...
7
votes
4answers
3k views

for a single-speed conversion, is it always necesary to change bottom bracket?

I want to convert my old raleigh, which has 3 chainrings on the front, into a single-speed. Do I have to replace the bottom bracket? I keep hearing conflicting things. Thankyou.
7
votes
2answers
9k views

How to replace old style cotter-pin bottom bracket with a modern one?

I have an old 1950's English bicycle with cotter-pin style bottom bracket like this: I find the cotter pins fail fairly regularly and are hard to replace correctly. I was wondering if it's possible ...
7
votes
2answers
2k views

Bottom bracket removal, what is this part?

I have a new (old) bicycle, and I am in the process of disassembling it. I arrived to the bottom bracket (with a cottered crank), and unscrewed the ring without problems, but then I'm faced with a ...
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 ...
7
votes
3answers
3k views

How do I stop my EBB (Eccentric Bottom Bracket) from creaking?

I have a '09 Felt Niner 29" SS with an EBB. After a thorough clean and reassembly of the BB the creaking will subside for a ride or so and then come back. Any suggestions? EDIT: the problem appears ...
7
votes
2answers
5k views

How can I keep my chain from falling off the inner chainring? (specifically, from getting stuck in the bottom bracket)

I've got a mountain bike which occasionally drops the chain off the lowest gear, and then the chain gets stuck in the bottom bracket. This happens while pedalling. Once the chain is there, it takes ...
7
votes
2answers
5k views

BB92 (Shimano bottom bracket) with SRAM 30mm crankshaft (X01 or XX1 BB30)?

The frame that I want to build has BB92 bottom bracket hole. The drivetrain I want to use is 1x11 SRAM XX1 or X01 with 30mm crankshaft (BB30)(edit: also available GXP). There are ways to fit it - ...
7
votes
2answers
687 views

When did Square Taper Bottom Brackets retire from racing?

I haven't been able to find any hard data on this. I have the impression that most top-end bikes made the switch around the year 2000. It would be great if I could get an answer for both of these: ...
6
votes
4answers
2k 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 ...
6
votes
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.
6
votes
3answers
7k 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
2answers
5k views

Pros and cons of gears in bottom bracket vs. rear hub? [duplicate]

Since 6 years, I am the happy user of a bicycle with a Rohloff internal hub gear. German quality squeezing 14 gears and a 526% gear range into the rear hub. Less known is the newer and equally ...
6
votes
6answers
20k 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 ...
6
votes
2answers
2k views

Is the plastic sleeve optional for a GXP bottom bracket install?

I took my frame to a bike shop to have the threads chased on the drive side. When I got home, I realized that they didn't install the plastic sleeve (because I didn't give it to them). They didn't ...
6
votes
2answers
7k views

Swapping cranks, but the new crank is wider, how do I compensate for this?

I was swapping the cranks and bottom bracket on my karate monkey from a Truvative stylo crankset (Mountain Double, GXP bottom bracket) to a Race Face Evolution DH (Mountain Triple, Race Face bottom ...
6
votes
2answers
113 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 ...
6
votes
2answers
561 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....
6
votes
1answer
8k views

Bottom Bracket terminology - English BB, SM-BBR60 BSA, English 68mm, ISO/English & BB30 confusion

My head is spinning with confusion on BB terminology, I'm hoping somebody can clarify things. I'm interested in building a road bike with the Dengfu FM098 frame and an Ultegra groupset that I would ...
6
votes
1answer
5k views

How hard is it to disassemble and reassemble a bottom bracket?

I ride an SE Lager. It's a pretty cheap and crappy bike. I've had to replace pretty much everything on it due to wear/breakage. The only area I haven't tackled is the bottom bracket. I can ...
6
votes
2answers
2k views

Is it possible to replace bearings in Shimano XT bottom bracket cups?

Curious if I can just replace the bearings in my existing cups or if I would need to buy new cups? If possible to replace them then what are possible high quality replacement bearings?
6
votes
1answer
493 views

Niner Biocentric I eccentric bottom bracket adapter won't budge

Niner Biocentric is the asymmetric bottom bracket adapter for a single speed. Below is the II. I have the I. I could not find a picture of the I. It is stuck. I have tried penetrating oil for ...
6
votes
3answers
1k views

Wobbly splined cranks, yet bolts are very tight

I have a road bike with ISIS splined cranks. I've been noticing front derailleur rub lately, and when I took a look, both of my crank arms are wobbly. The retaining nut is very tight, so tight on ...
6
votes
1answer
633 views

Does the BB axle (spindle) lengths 1:1 compare for square taper and octalink?

When measuring the axle length of a square taper bottom bracket, can I pick a new octalink bottom bracket with the same axle length? I can think of some offset added or removed by the difference how ...
6
votes
1answer
2k views

Bottom Bracket Compatability Question

Good afternoon all! In previous questions, I've mentioned that I intend to rebuild my 2000 Trek 7700 Multitrack. Well, I'm beginning by replacing the bottom bracket. According to the spec sheet I ...
5
votes
2answers
1k 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 ...
5
votes
5answers
2k views

Does (square-taper) BB spindle length affect Q factor?

I am having knee and ankle trouble on my commuting bike (1993 Specialized mtb) and this has a 73mm BB with a spindle length I haven't measured but there is space between crankarm and frame. I wanted ...
5
votes
2answers
2k views

How can I remove the bottom bracket from this old road bike?

I need some help removing this bottom bracket. I am obviously no mechanic, and watching several videos on youtube I found nothing that could help in this specific case. Basically after removing both ...
5
votes
1answer
379 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 ...
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
1answer
10k views

What are the advantages/disadvantages of press fit bottom brackets compared with threaded?

Many standards for bottom brackets have been gaining popularity recently such as BB30 and PF30. What are the benefits of these press fit systems over the threaded system that has prevailed for decades?...

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