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12

Pull your cranks laterally. Do they move? Give your cranks a good spin, preferably without the chain. Hear any unusual grinding noise or little clicks ? If you answered no to both questions, keep pedalling. You're still fine. It would be nice if the BB was always smooth as butter, but a little rough doesn't mean it's broken.


10

Your crank arm is trashed. With the crank bolt removed, gently ride around a few miles, it should work itself loose enough that you can yank it off. Otherwise many shops have basically a slightly larger crank puller for addressing this issue, where they chase out a larger set of threads, then use the larger puller to get it off. The crank arm typically ...


10

External bottom brackets allow you to have both large bearings and a large, hollow bottom bracket spindle. A large hollow spindle can be designed to be as stiff as a small solid spindle for less weight. Smaller bearings reduce the longevity of a bottom bracket, so the typical bottom bracket design allows a narrow range of suitable spindle sizes and bearing ...


10

Like you said, they are cottered, what makes them aligned is that pin through a hole, which at the same time tightens the crank arm around the axle. If you google "cottered crank", you can see the spindle, which has a slot in each side. My hypothesis would be: or the cottering bold got deformed, or the spindle slot itself got deformed, or both. A bolder ...


10

You need one of four things: An eccentric bottom bracket. Like these An eccentric hub. Like these Horizontal dropouts. Like these A chain tensioner. There are a number of different types. You only need one of the four, but these are the only ways to get the chain tension correct on a single speed. (I should say "almost only." Blind luck works every so ...


10

To prevent galvanic corrosion. When grease is appied, there is a thin film of grease that prevent direct contact between two different metal. To prevent water and contaminants, especially salt in the winter season, that would otherwise accelerates corrosion as discussed in (1) This will not work with plastic or carbon fiber (+epoxy as matrix) materials as ...


9

There are many possible causes of creaking. But Deemar has the most likely reason in this case - the cranks are loose on the axle. Think about how a creak is produced. It's one item sliding over another. But instead of sliding it's repeatedly sticking then jumping. The amount of movement might only be a fraction of a millimetre. The OP would have noticed if ...


9

Looking at the spec of your bike it says the BB is a cartridge unit. This probably isn't serviceable -- it's designed to be replaced when worn out, so just keep riding it until it grinds or gets excessively sloppy. The hubs might be serviceable. If you ride a lot in nasty conditions, or you're aggressive with the degreaser you might want to service them. ...


9

It's hard to tell from your picture because they're out of focus, but they look a bit like grease nipples: i.e. like the ones in the top left of the picture. Do they have the little ball bearing in the middle?


8

This is a very subjective opinion. A standard like "change your oil every 3000 miles" doesn't exist as far as I know, although here is a suggested one. I ride about 3,000-4,000 miles a year and my rule of thumb is to do the hubs every 300 - 500 miles or so, and the bottom bracket twice a year. Works out to a hub overhaul about every other month. Both of ...


8

There are several possible causes of noises you can get from your bottom bracket. Bad bottom-bracket bearings Bad pedal bearings Loose crank arms Loose bottom-bracket cartridge Loose chainrings Of these the loose crank arm (which may be silent or may be accompanied by a creak on each stroke) is probably the one needing the most immediate attention, since ...


8

You're right, you want to space it between the shell and cup. You can put spacers on either side to get the chainline right. Most cranksets come with spacers (2.5 mm is probably the most useful size for you) but if yours didn't any LBS should have a few to sell you. Something like this: http://wheelsmfg.com/bottom-bracket-spacer.html (I don't know if ...


8

Possible causes: There is "play" in the bottom bracket bearings, this could also explain the clicks. Usually this is quite noticeable, and you can check it by grabbing the crank-arm and trying to move it sideways. Usually this is not the cause for variable chain tension on singles; The chainring is "eccentric", either because of haveing been tightened ...


8

Without seeing any pictures, I think you'll likely want to replace both, but you can figure it out easily enough. Usually, the bottom bracket will be fine after a crank improperly coming loose. The bottom bracket spindle is typically made out of a hard steel and only the most miserable metal cranks are made from anything other than aluminum, so when the ...


7

If it's only 2 months old, they have to replace the broken part in guarantee for free. Isn't it? Anyways I checked the specs, this bike has Truvativ Firex GXP crankset. It has integrated bearing, so it should not move side to side. The clicking noise usually means loose or damaged bottom bracket. First I would try to reinstall the crankset with correct ...


7

You probably didn't remove material when you cross-threaded the bottom bracket shell in. If it's a steel frame, you can cut new (correct) threads with the correct taps. The taps are quite expensive, (they have to line up, and one is upside down, find a shop or local framebuilder who has one. Baring that you should chase the threads : grab old steel bb ...


7

I would avoid doing this. If the Teflon lube has any kind of solvent in it (which it probably does to carry the Teflon), it will break down the grease in the bottom bracket. Eventually, the grease will thin out enough that it will flow out of the bottom bracket, and No More Lube=A Very Bad Thing. If you are using a basic cartridge bottom bracket, they are ...


7

The core problem is that you need the thread on the bottom bracket axle to attach the new crank, and that will have probably been damaged by your welding. If you can get the bolt out after unwelding, it might be possible to keep the current BB. If your BB is this style, you might be able to cut the crank off, leaving enough of the bolt to weld on a small ...


6

if you are positive it's coming form the bottom bracket, and you have already R&R'd them, try using Teflon tape instead (plumber’s tape), wrap it around the cups and reinstall them - this should fix any squeaks in the BB.


6

The external bottom bracket uses the same thread size and shell width as an older internal BB. They were specifically designed to allow use in a standardized frame without redesign. They do require a new crank set, and depending on the model, and what is on your current bike, that may mean the purchase of extra components in order to be compatible with the ...


6

Looking at the photo I notice that the nut is missing,an indication that it has been worked on at some point. With the right side pedal in the 9 o'clock position the nut side of the pin will face up verify that the leftarm pin has the nut on the bottom.Several size pins were used and it is possible that you have two different sizes.I have several cottered ...


6

SRAM GXP bottom brackets can be user serviced, but it is usually unnecessary. To service your BB bearings, first remove the crank arms. Then place your thumb in the BB spindle hole, and bend the joint enough that your knuckle makes firm contact around the entire ring surface of the spindle hole. Pull outward using fairly firm pressure, and if necessary, ...


6

From Trek's archives and Bikepedia, it looks like that bike has an FSA Vero compact crankset (no mention of the bottom bracket (BB)). From the Amazon page for the FSA Vero Compact it appears the crank is compatible with a JIS square taper bottom bracket. JIS square taper bottom bracket is a common type of cotterless bottom bracket, available from many ...


6

in my experience. BB height affects stability of your ride, but mostly while standing on the pedals since you weight is then directly on the BB. but raising it 7mm may or may not make a difference in your ride. however, raising it ABOVE the axle height will make a dramatic difference in stability. BMX bikes are incredibly nimble (aka unstable) due to them ...


6

It's a bottom bracket cup. There are specialty tools you can use to remove it such as the HCW-11 on this page, or if it isn't rusted in, you can probably accomplish the same with an adjustable crescent wrench. Under there are some ball bearings, so make sure you don't lose any when you open it up. The bearings should be in a cage, which would stop you from ...


6

There are multiple components that can contribute to a clicking or grinding sound in your drive train in addition to the bottom bracket, including the chain, the pedals, the derailleur and the rear hub. That said, the symptoms you describe seem to indicate a problem with the pedal bearings or the bottom bracket. Here are my steps for troubleshooting the ...


6

Advantages: It's cheaper to manufacture cups, even with fine surface finish and reasonable tolerances than threaded shells. Especially with carbon frames there was an issue with inserting threaded shells which needed to have perfectly parallel faces. With press-fit cups and cartridge bearings having some factory loose, the tolerances are not so strict. A ...


6

Your bike has a conventional threaded bottom bracket (square taper). Since its a relatively new bike, it shipped with a sealed (*) bottom bracket. So, the only maintenance that can be done is tightening the bottom bracket cups (which hold the bottom bracket in place) and replacing the bottom bracket itself (which is a sealed unit containing the bearings, ...


6

The key measurement for chainrings is the Bolt Circle Diameter (BCD). If you imagine those four bolts being points on the circumference of a circle, then the BCD is the circle's diameter. As always, Sheldon Brown's site is a good reference here (and his crib sheet will help you work out your bike's BCD). So having found out your BCD, any shainring with ...



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