So what is the bottom bracket<\/em> on a mt. bike? The bottom bracket on your mountain bike is the bearings and housing that the crank arms and spindle rotate within. This component pulls multiple duties in that it works to keep the front chainring inline, as well as bear the weight of the rider and any of the forces that person may be transmitting into the pedals.<\/strong><\/p>\n\n\n\n The purpose of the bottom bracket is to bare the force of the rider’s pedal inputs and allow the pedals to spin free and smooth.<\/p>\n\n\n\n There are a ridiculously large number of different designs of bb’s used on bicycles today, but only a small handful of them can be found on modern mountain bikes. <\/p>\n\n\n\n Most will have some kind of bearing trapped inside of a machined housing that is either threaded or pressed into the bottom bracket housing, or frame. The crank spindle or axle is slid through the bearings in a very tight machined fit, that should have no play.<\/p>\n\n\n\n It’s tough to find an absolute answer as to where exactly the bottom bracket got its name. <\/p>\n\n\n\n Some claim it has been a term that stuck throughout the years of bicycle evolution, and that some of the earliest bicycles had a hanging bracket that house the bearings, crank, and spindle. At the time the fork and seat were attached via a bracket, rather than a tubular insert like there are seen today. <\/p>\n\n\n\n Rightly being named the fork bracket and seat bracket giving the lowest bracket on the bike its name, the bottom bracket. Though bicycle frame design has changed drastically since then, the name has stuck, even though it doesn’t much resemble a bracket any longer. <\/p>\n\n\n\n There are only minor differences between models designed for road and mountain biking. Mainly in the width of the tube that runs between the two cups and some variance in thread length.<\/p>\n\n\n\n Check your bbs manufacturer for exact details as to whether yours is designed for mtb or road bikes.<\/p>\n\n\n\n No. There is a multitude of different diameter, width, spindle, and bearing configurations, as well as press-fit, threaded or cup and cone designs the make up a list a mile long of varying types of bottom bracket standards.<\/p>\n\n\n\n This list goes on and on for bb’s and their manufacturers and there is no real standard set as of yet. <\/p>\n\n\n\n With all the different variables that play into BB life, such as trail conditions, rider weight, amount of load\/stress they experience, it can be difficult to nail down a recommended service interval for your particular bottom bracket, and riding parameters.<\/p>\n\n\n\n A general rule of thumb is to check the condition of the bearings by slipping the chain off of the front chainring, and giving the crank arms a quick spin. If the spin freely, with little to no drag, then they’re good to go. Notice any resistance or grittiness in the rotation? It’s time to service them.<\/p>\n\n\n\n Additionally, if you are able to perceive any movement in the bearing when pulling either crank arm outwardly, away from the bike, you might want to get the bike in the stand and show it some love.<\/p>\n\n\n\n The vast majority of BB’s on mt. bikes these days come with sealed cartridge bearings, which are intended to be run until they feel gritty when spun or they display excess play or slop. <\/p>\n\n\n\n Once the bearings have seen their life span, they can be pressed out and replaced with a new set, rather than having to replace the entire bottom bracket assembly.<\/p>\n\n\n\n However, if you are a little OCD and prefer to keep your ride in tip-top shape, most cartridge bearings can be repacked with fresh grease in order to greatly increase their life.<\/p>\n\n\n\n Simply, slide off the two seals on either side of the bearing using a pick, clean out the bearing with a good degreaser, I prefer Simple Green as it’s non-toxic and works to clean just about every part I choose on my bike. Reapply new grease to the bearing, while rotating it to evenly distribute the grease throughout the balls, then snap the seals back in and reinstall in your bike along with the spindle, cranks, and chain, and you’re set to go. <\/p>\n<\/div><\/div>\n\n\n\n Other manufacturers such as Chris King offer a special tool that slips into their bb’s allowing new grease to be injected into the bearings, eliminating the need to press the bearing out first before regreasing. <\/p>\n<\/div><\/div>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" After hearing this term used multiple times, it might be a little perplexing to understand what exactly a bottom bracket is by just its name alone. Examining this, not so obviously named…<\/p>\n","protected":false},"author":2,"featured_media":754,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_mi_skip_tracking":false,"spay_email":"","footnotes":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true},"categories":[4],"tags":[70,73,69,58,28,34,13,44,62,71,72],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.mtbikeprogress.com\/wp-content\/uploads\/2019\/11\/Scan0018-e1574465491913.jpg?fit=900%2C695&ssl=1","jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paJErm-c0","_links":{"self":[{"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/posts\/744"}],"collection":[{"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/comments?post=744"}],"version-history":[{"count":5,"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/posts\/744\/revisions"}],"predecessor-version":[{"id":755,"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/posts\/744\/revisions\/755"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/media\/754"}],"wp:attachment":[{"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/media?parent=744"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/categories?post=744"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mtbikeprogress.com\/wp-json\/wp\/v2\/tags?post=744"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/i0.wp.com\/www.mtbikeprogress.com\/wp-content\/uploads\/2019\/11\/bottom-bracket.jpg?resize=640%2C425&ssl=1\")
<\/figure>\n<\/div><\/div>\n\n\n\nWhere Did it Get its Name?<\/strong><\/h3>\n\n\n\n
![\"\"](\"https:\/\/i0.wp.com\/www.mtbikeprogress.com\/wp-content\/uploads\/2019\/11\/Cognet-Safety-Cycle.jpg?resize=585%2C336&ssl=1\")
Are ro<\/strong>ad bb’s different than mtb bottom brackets?<\/h3>\n\n\n\n
Are all bottom brackets the same?<\/strong><\/h3>\n\n\n\n
How Often Should I Service My BB<\/strong>?<\/h3>\n\n\n\n
Is It Hard to Service a Bottom Bracket?<\/h3>\n\n\n\n
![\"\"](\"https:\/\/i0.wp.com\/www.mtbikeprogress.com\/wp-content\/uploads\/2019\/11\/Clean_bearing_1024x1024.jpg?resize=640%2C239&ssl=1\")
<\/figure>\n\n\n\n![\"\"](\"https:\/\/i0.wp.com\/www.mtbikeprogress.com\/wp-content\/uploads\/2019\/11\/CK-bb-injector-e1574460641109.jpg?resize=300%2C208&ssl=1\")
<\/figure><\/div>\n\n\n\n