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Questions and answers about sports

Bottom Bracket Movement

6 min read

Asked by: Vanessa Lewis

Why is my bottom bracket moving?

If there is play in your bottom bracket it means that the bearings are loose or worn out, it should be repaired soon because it will influence the whole drivetrain negatively, like sprockets and chain.

How do I know if my bottom bracket is loose?

How to spot a loose BB. Firmly hold the bike steady and attempt to move the crank from side to side – in the opposite plane of motion to its rotation. If there is any play from side to side, the BB system is loose. An open/loose BB will need its bearings adjusting (via the adjusting cup) or replacing.

What do I do if my bottom bracket is loose?


Quote from video: Up it anti-clockwise to loosen you can then unscrew the rest by hand net do we use the spanner fix it onto the hex head and tighten by turning it in a clockwise. Direction.

Why is bottom bracket creaking?

Most of the time, the true cause is a loose chainring bolt—tighten them up and that’ll quiet most creaks. After you check the chainring bolts and if you still hear the noise, look at your pedals, crank bolts, seatpost, and seat. By checking these first, you’ll save an hour of digging into your bottom bracket.

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 you replace a bottom bracket?

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.

Can you over tighten bottom bracket?

If the BB is too tight, it will not rotate without grinding or feeling stiff. In fact, if you ever tighten an adjustable (open/loose) BB to an extreme, the BB will not move at all. If you diagnose this problem in an open/loose system, you must loosen the adjustable cup until the stiffness lessens.

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.

Should I grease my bottom bracket?

In the case of the bottom bracket, you will use the grease when you install it, whether it is threaded, press fit or similar, and in the same way when you install or clean the cranks. The point of contact of the cranks with the bottom bracket should be greased too.

Why does my bike creak when I pedal hard?

That creaky squeaking you hear as you pedal “could mean that [your bike] has a dry chain or bearings,” Yozell says. Cleaning and lubing your chain is usually a good place to start with any weird noise, but if it doesn’t solve the squeak, you may need to maintain or replace some bearings (see below).

Why does my bike creak when I pedal?

Squeaks and Creaks:



These super common sounds are usually due to DIRTY or DRY bearings. You’ll often find that after riding your bike for a while or in harsh conditions these noises start to creep in. Areas to check if you’re hearing these noises would be: Crankset/ Bottom Bracket.

Why is my cranks creaking?

The most common cause of a squeaky crank is that the bolt is loose. Check for play in your cranks by pulling on one side and trying to wiggle it side to side. If there is play, check that your crank bolts are tight using a hex wrench—bolts should be hand-tight.

Why do bottom brackets fail?

The fail by water and grit entering the bearing and causing the cartridge bearings to get loose. This is felt by poor shifting or chain rub, and finally the bearing can get very stiff if the balls jam up inside. External bearings can be cleaned and adjusted. Most have some sort of seal that can also be replaced.

Do bottom brackets wear out?

Registered. bottom brackets do wear out over time. sometimes if your bottom bracket is making noise or not spinning freely you’ll have to take the bottom bracket out, regrease it and put it back in. if your going to buy a new bb you’ll need to know what kind and what size your bike uses.

How long does a bottom bracket last on a mountain bike?

They SHOULD last 3000 miles!

How do you tighten a bottom bracket cartridge?

Quote from video: This is going in nice and easy now. So I know the threads are lined up take your bottom bracket tool. And continue to tighten up by hand until it starts to get a little snug. And then finish.

How do I Unseize my bottom bracket?

Quote from video: Directly down at the bottom bracket or it can also be sprayed by removing the seat post. And sprayed straight down and giving it a chance to soak in to free those threads.

How do you tighten pedal bearings?

To tighten the pedals, turn the right pedal clockwise and the left pedal counterclockwise.

How do you tighten a bike crank?

Quote from video: Now using the screwdriver tighten up the cones they it takes out the play in the cranks and secures the bearings of the correct. Place do not over tighten.

Why does my crank keep coming loose?

If you’ve been repeatedly riding with a loose crank arm it could be that it’s now damaged. You could try tightening with lots of torque, grease on the square taper and threadlocker (e.g. blue Loctite, but in a pinch any kind of glue works) on the threads.

How tight should my cranks be?

Quote from video: We put the tool in the cap. Just a couple of fingers will do us about four inch pounds. Sometimes not that much if you bring the crank arm over to the bearings.