What kind of Bottom Bracket is this? And what is broken?

Asked by: Jane Munoz

How do I know what type of bottom bracket I have?

Quote from video: Found at any point here by hitting the information icon in the corner. The bottom bracket is the bearing system between your bicycles cranks.

How do you know if my bottom bracket is broken?

To check if your BB needs replacing, drop the chain off of the smallest chainring and spin the cranks. If there’s a side-to-side wobble, or feeling of grittiness, it’s time for a new one.

What does a broken bottom bracket sound like?

As the crank arms are rotating, the bottom bracket will make a dry creaky noise, and is usually caused by axle oscillation around dry bearings, where the grease inside has been washed out of the many contact points,” he says.

What happens when bottom bracket fails?

The most common symptom of a loose or worn bottom bracket is rhythmic creaking with each bikes. The crank-and-spindle interface is made up of eight splines (ridges that keep the spindle in place), creating more surface area for a better fit.

What is the difference between BB30 and BSA?

BSA is English standard and have screw thread inside the hole ,usually use in shimano,while BB30 is Italian standard and don’t have screw thread, usually use in CP.

What are the different types of bottom bracket?

There are two main types of bottom bracket design, one with a threaded shell which the bearings screw into, or a press-fit design which the bearings press into the shell.

Can you ride with a broken bottom bracket?

If it’s your crank arm moving on the spindle, don’t ride your bike. If it’s coming from inside the bottom bracket and it’s an internal BB, you’re fine. If it’s an external BB, it’s a bit riskier.

How many miles should a bottom bracket last?

As for a bottom bracket, on the low end, maybe 5000 miles. The basic Shimano one most people use (UN51/55/similar) can reasonably expect 10k+ miles. But sometimes you get unlucky and get a bottom bracket that lasts maybe 500 miles.

How often should a bottom bracket be replaced?

Every three months or so I’ll take the cranks out and if it’s a threaded bb, I’ll remove the bb and do the full service. Around the three month mark is normally enough time, even in the best conditions for dirt to work its way into the small gaps and contact points around the crankset and bottom bracket area.

Why does my bike make a clunking sound when I pedal?

Wheel Noises Only When Pedaling



Noises once-per-wheel-revolution that only occur when you are pedaling are most often related to the freewheel or Freehub. The freewheel or Freehub bearings may be loose, or the cassette may be loose on the Freehub body. See if you can wiggle the sprockets back and forth.

Why does my bike clunk when I pedal hard?

The chain may be rubbing against the cage of the front derailleur, hence causing the noise. In that case, you need to trim the front derailleur. The chain will rub against the derailleur only in some gears since it changes its angle as you shift gears. That’s why your bike makes a clicking noise when pedaling hard.

Why is my bike making a scraping sound?

Scrapping and Popping:



Likely the most common of all the annoying bike noises, scraping and popping usually occurs when there is an issue with your derailleur or shifting.

Is BB92 the same as PF92?

The frame’s bottom bracket shell inner diameter is 37mm. A bearing with an OD of 37mm is pressed directly into the frame. Trek is moving away from the BB90/95 system to what they call PF92, which is the same as a BB92 (41mm ID shell and 92mm width).

What is a hollowtech bottom bracket?

HOLLOWTECH technology is an ultra-lightweight hollow crankarm created by SHIMANO with the company’s own proprietary forging technology that also maintains rigidity.

What is BB68 bottom bracket?

BB68/73S | Bottom Bracket, makes matching your bike’s bottom bracket shell to your crankset’s spindle easier. FEATURE. + Easy to install. + Suitable for both 68 and 73mm shell widths. + Improves sealing against the elements while reducing seal drag.

Is BB92 the same as PF92?

The frame’s bottom bracket shell inner diameter is 37mm. A bearing with an OD of 37mm is pressed directly into the frame. Trek is moving away from the BB90/95 system to what they call PF92, which is the same as a BB92 (41mm ID shell and 92mm width).

How do I know what crankset I have?

Print. Shimano cranks are all identified with model information above or surrounding the area on the backside of the pedal threads. For example; FC-6700/6750 = Shimano Ultegra. The crank length is often located in the same area, which is helpful to note before placing an order.

Is PF30 and BB30 the same?

ARE PF30 & BB30 the SAME? No they are not the same. But they are also not all that different. 6806 is a number you’ll see describing the bearings used for both pf30 and BB30.

Is Shimano JIS or ISO?

Shimano and most other Asian manufacturers employ the JIS standard. Campagnolo and other European manufacturers use ISO.

How can you tell JIS from ISO?

ISO and JIS are very similar – the angle of the taper is the same, but the ISO spindle ends are a little slimmer. In a pinch, you sometimes can use a JIS spindle with an ISO crank. To compensate for the wider JIS taper, select a spindle that is about 1-2 mm shorter.

What does JIS mean on bottom bracket?

the Japanese Industrial Standard

J.I.S. is the Japanese Industrial Standard, and is generally used on square taper cranks made in Asia. All of the common black spindles identified with standard numbering use the J. I. S. taper. Many of these have a threaded boss for a nut on each end, rather than being hollow and threaded internally for a bolt. J.I.S.