EDIT 2024: If you have any questions, please use the BikeGremlin forum (I try to respond to every comment, but KZfaq sucks at notifications, especially when it comes to any follow-up questions): www.bikegremlin.net/ Here is a better explanation (with a drawing) of the difference between the ISO and JIS taper standards: bike.bikegremlin.com/1634/bicycle-bottom-bracket-standards-explained/#jis-vs-iso Relja

Very clearly explained in a language which is not his own. Good job!

I am changing cranks on a bike and every part of it is from different bin. I felt lost but you made it all perfectly clear thanks man.

I have been looking for a video like this.

You did an excellent job! I have rebuilt a few bikes, perhaps 60 or so and I am considering moving an old Giant Perigee to a triple crankset using a bit longer bottom bracket. The original BB for a double Shimano Biopace crankset measured 116mm but I’m only going to move up to 118mm and see how much clearance is present. I wish I had looked at the clearance before I pulled the crankset but it won’t take long to reinstall and check the spacing. 118mm was a frequently given length for a triple crankset on the Harris Cyclery (Sheldon Brown) webpage. Thank you for making this video sir!

Thank you for your expert instruction...just perfect for sizing appreciated quite sure I will order the right part...Thank you hope your well have super evening....

Exactly what i need! Thank you

Very helpful, thanks. Just in the process of deciding on the right size. I had 2, one of 122.5 which worked, but there was too much space and made gear changing "clunky". I fitted my spare, which is 110, but now the smaller gear is only about 0.5mm from the frame, even with a small spacer added (although gear changing is excellent".). Think I actually need something like 113 or 116.

nice informative vid! thanks

Good video, thanks!

Very clear, thank you so much. Mike in Bristol Uk

Nice ! thank you to help me !

Cool vid. I believe I have read your article on chain line, good stuff too. Chain linen can further be affected by how much you tighten the crank arms into the BB axle, but newer Shimano BBs have a disc at a determined portion of the axle (drive side only) and call it something like chain line keeper.

Here are some comments from over 45 years of working on bikes. You can check your chain line by looking backwards through the gap between your chain rings at the cluster. Another way is to slide a stiff metal yard stick between the chain rings and lay the back end of the yard stick on the cluster. I have a number of older bikes (road and mountain) that still use tapered cranks. I long ago dumped all their original bottom brackets and replaced them with Phil Wood Sealed Cartridge Tapered Bottom Brackets and their associated Cups. While these are expensive you cannot purchase a better looking and operating tapered bottom bracket and they literally last for decades. They come in all style tapers, axle lengths and threads to fit any model frame and crankset. Their proprietary Cups use a special wrench and actually totally thread into the bottom shell from both sides and grab the cartridge allowing the cartridge to be moved back and forth somewhat to finis your chain line when installing. They last for ever and can be rebuilt for minimal cost by the factory. They also have longer tapers on their axles which allows reuse of cranksets that are bottoming out on regular tapered axles (which can happen after to many removals and installs). I have some that are 40 years old and still working and they spin better the more they are used without any play. I cannot recommend them enough other than the initial costs (cartridge, cups, and wrench over $200) but they are literally a set and forget item which pays off in the long run as little or no maintenance. www.philwood.com

Hello. Thanks for this explanation. It was helpful. I do have a situation with my bottom bracket and chainrings. My BB is a 115mm length (68mm) with a triple chainrings and unable to shift to the small chainring because my front derailleur (clamp on) butts against the seat post and therefore does not have the proper spacing. After listening to your information, I should consider a 122mm BB. For which I assume it will push the chainrings further away from the frame. Is that correct? The difference of 7mm between the 115mm and 122mm , is that split equally on both side of the frame? Thanks for your time.

this is the follow up video that Simion from GCN did not include in the video Bottom Bracket Standards Explained, he was to tired to explain how many bottom brackets "Standards" are there.

question! how do I confirm that my BB has a 24TPI or 26TPI thread? the bike in question is an old BSA made in late 80's and desperatly wants an upgrade from cup & cone to sealed bearings. THANKS

On a Shimano un300 BB, does the inside of the crank seat up against the chain stabilizer collar?

hello, i have a problem with my new crankset that i bought, it seems that the square holes of it is much bigger than my old one as it just slides through to the entire length of the spindle, for reference my current bb spindle length is only 103mm which works well with my old crankset, does crankset square hole sizes differ too?

Hello all. I have a bike with a M48 Bottom Bracket. I want to upgrade my drive train to shimano xt. The xt BB is obviously smaller so I’m wondering if they make some type of thread in step down or if another option is available?

I have 7 gears at the back and want to convert to 1x chainring, how long do i need for it ?

Can I use 68mm in 73mm shell? (square bottom bracket)

What happens if you can't find the length you need? I've got a 125mm that seems to be an odd ball size.

R you Turkish?

смотрел как глухонемой --поучительно но жаль што ты на РУССКОМ не базаришь .