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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Tiny dent near the bottom bracket of a new hardtail - should I be concerned?

I’ve just purchased a new Trek Roscoe 7 (aluminum hardtail mountain bike) recently and I’ve noticed this tiny little dent today. It is on the drive-side chainstay near the bottom bracket. Should I ...
TommyYOyoyo's user avatar
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1 answer
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2018 Diamondback bottom bracket size

Does anyone know what size a 2018 Diamondback Line bottom bracket is?
Sam44's user avatar
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1 answer
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Can someone please give some advice to help find a new crankset?

I apologize in advance if I mix-up some lingo, I have almost no experience in fixing bicycle drivetrain. Previously I had Comet CKM-7159 as crankset (I managed to find this datasheet that seem to ...
kazaker's user avatar
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4 votes
1 answer
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How to remove and replace wire pins from axle?

I have a Kent adult tricycle. It has a band brake attached to the rear axle. The brake pad is old and no longer grips, so I need to replace it. Apparently I can't just replace the pad because it is ...
causative's user avatar
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3 votes
1 answer
224 views

Should I use fiber grip or grease when installing a bottom bracket into a carbon frame?

I am assembling my first carbon road bike and came across a question regarding on how to install the bottom bracket. I decided to go for this Ninja BBRight for my Cervelo Caledonia. The Token's ...
Bob's user avatar
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6 votes
1 answer
406 views

Noisy bottom bracket SHIMANO BB-RS500

About a year ago I've got this Stevens Supreme fitted with Shimano Tiagra BB-RS500 bottom bracket. In less than 2 months it started clicking and screeching loudly which only had gotten worse over time....
Petr Gladkikh's user avatar
3 votes
1 answer
205 views

How can I know if I need spacers for my bottom bracket / crank?

I am assembling a bike on my own and came a cross the topic spacers for bottom bracket/crank. I am installing a Shimano FC-R7100 crank with the bottom bracket model SM-BBR60. By taking a look at the ...
Bob's user avatar
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8 votes
2 answers
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Another very stuck bottom-bracket – non-standard size (37 mm flats)

my name is Alex and I’m new here. I’m a bit of an amateur but I’ve decided to attempt the modernization of an old French Liberia racer from 1978. The aim is to create a bike I can use as a daily ...
TooMuchCoffeeMan's user avatar
2 votes
2 answers
479 views

Which tool to remove this bottom bracket nut - photo provided

I have an Apollo Transfer 21 inch frame and need to remove the bottom bracket. It seems to be a screw in bottom bracket. I am new to bicycle maintenance by the way. I tried a 26mm spanner to remove ...
Angus Comber's user avatar
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1 answer
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Trek crossrip ltd 2015 bottom bracket model

Hello I have a Trek Crossrip ltd 2015 gravel bike. The frame is alpha aluminium 100 series and the bottom bracket is Hollowtech II. What bottom bracket should I replace it with?
Harri Juus's user avatar
2 votes
1 answer
55 views

Shimano BB: add grease over threadlock?

The dealer manual for the Shimano BBR60 bottom bracket says to grease the threads of the cups before inserting. But I noticed that the threads have some kind of grey threadlock compound applied to ...
someguyinafloppyhat's user avatar
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1 piece to 3 piece crank conversion

I wish to convert my 1 piece crank to a 3 piece crank. I have a conversion kit that presses into the bb shell and accepts a cartridge style bb. I went to order one and realized I have no idea what ...
Raymond Dunne's user avatar
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56 views

Damaged carbon fibre [duplicate]

My chain dropped and got stuck in my bottom bracket while I was going uphill. I think the force from the pedal stroke damaged the carbon fibre. Wondering what is recommended when something like this ...
Jocelyn's user avatar
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32 views

What is the correct BB spindle length for Kooka cranks?

Does anyone know the correct square taper bottom bracket spindle length for an early 90s Kooka triple mountain bike crankset?
Noah Sutherland's user avatar
3 votes
2 answers
85 views

BB snapped and stuck inside shell of euro threaded frame?

I was in the process of prepping to install a new BB on my bike when I noticed this remnant that I believe might be part of my old BB. To my novice eyes, it looks like something snapped and is now ...
Terry T's user avatar
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1 answer
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Which mid drive motors use the same frame interface?

One concern with mid drive e-bikes is that if the motor breaks in ten years, probably there is no exact replacement available. But do the manufacturers keep the same interface for their different ...
Nobody's user avatar
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4 votes
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Bottom bracket has play. Can I still tighten this, or do I have to replace it/fix it properly? Tools? (incl. videos and photos)

I'm staying with a relative and borrowed her bike for a ride. It now has play on the bottom bracket - as shown in videos below. TL;DR Is it possible to judge if I can still just tighten this, or do I ...
pateksan's user avatar
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3 votes
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Frame and bottom bracket compatibility

I have problems with adjusting front shifting on my MTB so I suspect something is wrong elsewhere. This is a 27.5" Merida Big Nine 100 XC MTB. Its chainset has been replaced with a Shimano FC-...
Ender's user avatar
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3 votes
0 answers
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Request for clarification of bottom bracket threading

I know that bottom brackets have a left-hand thread on the right side, and a right-hand thread on the left side. But I fail to understand why. I would have thought it should be the other way round, to ...
Burki's user avatar
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2 votes
1 answer
52 views

BB/Cranset creaking on/off

I'm having an issue with a creaking sound on a brand new bike (see video below). It seems to happen after 30+ min rides, you can faintly hear it when the pedals are spun backwards but this usually ...
Jordan's user avatar
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6 votes
1 answer
179 views

Small metal pellets in a new frame

I am working on assembling a new boxed bike (aluminum Kona Libre), starting by tearing it completely down and making sure all components are properly installed, greased and adjusted. The headset felt ...
djwicket's user avatar
1 vote
0 answers
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Headset and BB compatibility Kona Rove LTD 2019

I've got a Kona Rove LTD 2019 and it's about time to change bearings. This is the exact model : https://99spokes.com/en-EU/bikes/kona/2019/rove-ltd I'd like to change headset and BB because they're ...
Florian F.'s user avatar
5 votes
4 answers
723 views

BB drop vs BB height from stability perspective

While I have heard that a lower bottom bracket tends to give more stability, I'm confused as from which point of reference yields such an effect, from the wheel axle (BB drop) or from the tire contact ...
Gregory Leo's user avatar
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4 votes
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BB386 bottom bracket - clicking noise once per rotation

I've been posting quite some videos about defects on my bike her recently, so I seem to be a winning streak. On my last ride, a strange noise started to occur on my bike. Might be that it was ...
DoNuT's user avatar
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5 votes
2 answers
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Threadlock for Bottom bracket on Titanium Frame?

I'm looking into installing a bottom bracket for my titanium bike frame. The bottom bracket that I purchased (SHIMANO ULTEGRA Threaded Bottom Bracket 68/70 mm shell width) seems to have some kind of ...
user1301593's user avatar
1 vote
2 answers
53 views

Front chain rings don't shift properly after installing a bottom bracket and shorter spindles

My problem is I fitted shorter spindles and a new bottom bracket now front gears are not working as they should, the chain on the third click should be on the outer sprocket but only goes to the ...
jim cooper's user avatar
1 vote
0 answers
28 views

Replacement BB chainline check?

I want to replace a bottom bracket (to add a torque sensor for a recent ebike conversion). Current BB spindle length is about* 114mm, replacement is 127mm. So, all else equal, we're talking about ...
bike_tourist's user avatar
6 votes
3 answers
574 views

Broken plastic HollowTech II BB spacers, why?

Yesterday I was installing a BB-MT501 HollowTech II bottom bracket into my ~2006 Trek 520 frame. This frame has a 68mm BB shell. I was following the directions on Shimano's website: https://si.shimano....
Dan's user avatar
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1 vote
1 answer
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Crankset compatibility, old 105 SC to new Claris FC-RS200

My bike currently has an old 105 crankset. It's a 105 SC, from 1989. The rest of the components are Claris R2000. I'd like to replace the crankset with a new one with smaller rings. I thought of the ...
elcye's user avatar
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-2 votes
4 answers
159 views

Confidence in carbon bike frame after sealed bearing replacement

You buy a new bike. The bottom bracket makes a funny noise and needs replacing. For many other product categories (computer with a noisy fan, ...), you'd worry you had a lemon on your hand. It would ...
Sam7919's user avatar
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5 votes
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What is this type of bottom bracket and is it serviceable?

I encountered an old and beat up bike today with the bottom bracket pictured below. I could feel play in the bearings but did not see any lock ring or adjustable cup. The 14 mm bolt of each crank arm ...
olliebulle's user avatar
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0 votes
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Giant Reign 2 2017 GXP pressfit BB

I am currently running a 10 speed groupset on a Giant Reign 2 2017 and I am looking to upgrade to a 12 speed DUB groupset. I'm wondering if this is possible with my current bottom bracket or what ...
Jake Wright's user avatar
1 vote
1 answer
182 views

Bottom bracket to replace a Shimano BB-UN100?

The Shimano BB-UN100 68/122.5 bottom bracket that came with my 2018 Giant Roam 2 feels rough and creaks. Searching the web, it is hard to find new BB-UN100 brackets. I would like to upgrade to a ...
Doug Montgomery's user avatar
0 votes
1 answer
77 views

Ekar compatibility with UT bb and 6805 bearing

So I've got ekar chainset and pro tech bb, didn't have a correct bearings so fitted 6805 which are 7mm width, because its 1mm wider than original I've got +2mm over. Cannot see if it's pulling enough ...
Virmantas's user avatar
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0 answers
37 views

How to remove threaded crank arm [duplicate]

I'm trying to service my son's bike that was left outside over the winter. I'm not sure what type of cranks and bottom bracket I have. The crank arms seem to be threaded and the bottom bracket looks ...
sReall's user avatar
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0 answers
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Raleigh men's venture 7speed comfort bike xl steel frame bottom bracket bracket removel tool's needed

I have a Raleigh venture 7speed XL 22 inches steel frame men's comfort bike. In doing an internet search it comes up with venture 2,3,4 with aluminum frame mine has a steel frame. I can't find what ...
George Murrieta's user avatar
4 votes
1 answer
737 views

Is it possible to damage the crankset while removing the pedals?

I got a brand new bike and I wanted to replace the pedals with the ones from my old bicycle. However, while removing the pedals from the new bike, I forgot that one of the threads was reversed and ...
fabda01's user avatar
  • 209
12 votes
2 answers
1k views

What kind of tool do I need to change my bottom bracket?

I want to replace my bottom bracket, but I have no idea what kind of tool to use. What kind of bottom bracket is this? What tool do I need to change it?
Simon Hüning's user avatar
2 votes
3 answers
174 views

Breaking a chain must be an opportune time for a list of tasks; what are they?

After breaking a chain off and before installing a new one I will set aside time to do two tasks: Inspect and perhaps overhaul the RD pulleys without wrestling with the chain. Turn the crankarm and ...
Sam7919's user avatar
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1 vote
1 answer
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Old Raleigh Marathon road bike with new Shimano 105 crankset – What bottom bracket is needed?

Hey guys first time poster. I have a Raleigh Marathon road bike and I am pretty sure it’s an ‘85. The crank arm has been falling off so I have decided to just replace the whole crankset. I have been ...
Devin_L's user avatar
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3 votes
1 answer
332 views

Clicking / cracking noise rotating crank MTB

Suddenly during the ride, strange cracking noise started to happen. It happens even without a chain. The crank seems to rotate smoothly otherwise. There are more cracking noises when rotating forward. ...
petrsyn's user avatar
  • 133
2 votes
1 answer
81 views

BB86/92 spacer hollowtech Ultegra 8150

I'm having some issues on my new road bike which I am setting up. It's a Canyon Ultima CFR frameset which came out of the box with the handlebars, Dura Ace 9200 wireless shifters and brake calipers. I ...
Pieter_Daems's user avatar
7 votes
1 answer
459 views

Loose bottom bracket on MTB

The bottom bracket on my MTB is loose. I am able to slide it from side to side as can be seen in this video: https://photos.app.goo.gl/CWmA8afBaA6GtDvq6 It seems to be a pressfit BB I have. I have ...
Lars Høyrup Jensen's user avatar
0 votes
1 answer
61 views

What crankset fits BH Ultralight RC?

This is somewhat related to an issue I had previously posted. The shop initially said it was the cassette, but after a thorough check-up, the shop told me that the issue is the wear & tear of the ...
rbhat's user avatar
  • 241
2 votes
1 answer
96 views

Cranks shift from side-to-side in new (second hand) bike

Just bought a new bike (second hand) and I've noticed that the cranks or perhaps the bottom bracket slides from side-to-side, almost as if the bottom bracket isn't long enough for the bottom bracket ...
Ashton O'Connell's user avatar
4 votes
1 answer
314 views

How do i remove my crankset and bottom bracket?

I have a Specialized Hardrock I'm trying to remove the crankset and bottom bracket from. It's a square taper crank and I do have a Parktool CWP-7 however I have yet to understand how to use it exactly ...
Alison's user avatar
  • 817
6 votes
2 answers
882 views

Removing a 1970s Schwinn Bottom Bracket

I am restoring a 1970 Schwinn Suburban and I am at a loss when it comes to removing this bottom bracket. The crank arms do not come off normally (no way to use a crank puller) and they won’t unscrew. ...
duhnlic's user avatar
  • 141
6 votes
2 answers
197 views

Crankset repeatedly degrades even after bearings and brackets replaced 3 times - what's wrong?

I'm repeating words that the bike shop told me or from a google search. This bike seems to be defective since purchase. It's a Schwinn Men's GTX3 Hybrid with 700c wheels. Within a few weeks the pedals ...
Jack's user avatar
  • 61
4 votes
1 answer
95 views

Old Colner (Campagnolo) frame - What bottom bracket do I need?

Just picked up an old steel Colner frame. Don't know model or year. Tried to put my Sugino bottom bracket in but it's too small. The width of the frame where the bb goes in is 70mm, and internal ...
Jetzki's user avatar
  • 41
1 vote
0 answers
93 views

Vanmoof bottom bracket sensor

I have a Vanmoof S2 and had the bottom bracket replaced ~6months ago. Now I experienced cutout of the motor again and recently no support at all. I disassembled the bike and found no signs of wear of ...
Paamand's user avatar
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