How long does a bottom bracket last?

Asked by: Kevin Simmons

Properly maintained, an average entry-level hybrid or street bike bottom bracket from a reputable parts company should last indefinitely, or for at least 100,000 miles.

How often should a bottom bracket be replaced?

First, you should know when it’s best to service or clean your bottom bracket and crankset. At the very minimum, I do it about each season change, but normally more. 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.

How many miles will 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 do I know if my bottom bracket needs replacing?

Changes are likely to be compromised. As well. But if it's just making noises. It might just need taking apart cleaning and servicing re-greasing and putting back.

How long should a bottom bracket bearing last?

Simple rule is (unless you’re starting a long trip) “if it ain’t broke don’t fix it”. Do normal maintenance, keep things properly lubed and your BB should last for another 4,000 miles or more.

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.

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.

Do I need to replace bottom bracket when replacing crankset?

To answer your question specifically, yes cranksets require a specific bottom bracket, especially so the new offerings from SRAM and Shimano and others.

How do I service my bottom bracket?

So coming on to the bottom bracket we're just going to clean up each individual part is worth noting if your bearings are a bit worn you actually want to take them apart regress.

How do you fix a squeaky bottom bracket?

If it doesn't sort your creaking cleats out then take the bolts out clean. And we greased these as well. And then we actually put Loctite on a medium strength lock tight when doing them back up again.

How much does it cost to fix a bottom bracket?

How Much Does It Cost To Replace a Bottom Bracket? A new bottom bracket can vary wildly in cost, from $15 all the way up to $250(£10-£180), so it largely depends on how much you are willing to pay.

How long do bottom brackets last MTB?

They SHOULD last 3000 miles!

Why is my crank clicking?

A clicking sound every third revolution of the pedal. Often indicates either stiff link or partially broken chain.

Can you service a sealed bottom bracket?

Servicing them may be possible only if the design has the bearing seals exposed. Full one piece sealed cartridge style bottom brackets (octalink,square taper) are simply replace only. Depending on which sealed cartridge you have, you would need the appropriate tool to remove and replace them.

How do you replace bottom bracket bearings?

So make sure the biker frame is fully stabilized. And the wrench is fully seated on the cup. Once you break the cup free it should thread out easily. And you can most likely turn it with your fingers.

What grease should I use for my bottom bracket?

For the bottom bracket and most bicycle components , generally it is just a multi-purpose bicycle grease, on bottom brackets anti-seize should be used if it is a titanium frame or mismatched metal that are known to seize or bond to one another, but can be used in other frames as well.

What are bottom bracket spacers for?

Bottom bracket spacers are used to adjust the spindle position to add extra clearance, or to fine tune chainline. For example, if your inner chainring is too close to the chainstay you can add spacers to move the crank outward just a bit. They are really great if you want a perfect chainline on a fixed gear bike.

How do I know my bottom bracket size?

To find out the size of bottom bracket needed, measure the inside of the bottom bracket shell in your frame, it will be 73mm, 70mm or 68mm. Some older frames may have Italian threaded bottom brackets, instead of the more modern English.

Do bottom brackets make a difference?

(Click here to read BikeRadar’s complete guide to bottom brackets.) According to Friction Facts’ latest report: “No statistically significant difference exists showing a general advantage or disadvantage of a standard type under similar loading conditions.

Do all cranks fit all bottom brackets?

Crankset compatibility



In general terms, most cranksets can be fitted to a variety of bottom bracket shells, though much of this compatibility depends upon the availability of suitable hardware (see next section). Any incompatibilities that do arise are often related to the length and/or diameter of the crank axle.

Can I put any bottom bracket on my bike?

To a certain extent which bottom bracket you end up buying is up to what kind of frame you have. Certain frame materials and drivetrain options only support one type of Bottom Bracket. There are two main types of bicycle bottom brackets in today’s market, namely, threaded and press-fit BB’s.

What BB does Shimano use?

Shimano BB86



Shimano developed its press-fit standard using 41mm diameter bearing cups with an 86.5mm wide bottom bracket shell for the road, and 89.5 or 92mm for mountain bike.

Are all bottom bracket threads the same?

Threaded bottom brackets shells have been made over time in various thread standards that are not interchangeable. The common threaded bottom bracket uses cups or adaptors with the thread specification of 1.37″ x 24 threads per inch (approximately 34.8mm diameter).

What does the 90 in BB90 refer to?

BB86/92 and Trek’s BB90/95 are often misidentified. While the “30” in BB30/PF30 references the inside diameter of the used, the numbers in BB86/92 and BB90/95 refer to the width of the frame’s bottom bracket shell.

What is the difference between English and Italian bottom bracket?

The key difference is in how the two thread into the bottom bracket shell. Like pedals, one side of a BSA standard bottom bracket shell is reverse (left) threaded, while both sides of an Italian standard bottom bracket shell are regularly (right) threaded.

Can I use a 68mm bottom bracket in a 73mm shell?

Multiple spacers are included in order to fit both sizes meaning if you see a BB for sale that says 68/73 it means it will fit both but it includes a couple spacers in the box to make it fit the 68, those spacers (or fewer of them) are not needed if the shell is 73mm wide.