I am stupid, but bottom bracket sizes

[snakebite]

what does its mean when it says 68/118 for the bottom bracket? is 68 the spindle size? whats number in 68/118. does the 68 represent the bottom bracket width?

[Ebon Dragon]

118 would be the width and 68 would be the shell size (im pretty sure). Edit- oh yeah by width i mean spindle length

[RomanR]

Here's a couple of pics, with an example of bb sizing.


http://www.observedtrials.net/otn2/bb.JPG


http://www.observedtrials.net/otn2/bb2.JPG

[rush]

The question isnt stupid at all. I didnt know that either. Duh.

Thats why there is a beginners section, so people dont feel stupid asking questions.

Neatly done Roman.

[AgrAde]

i think it's just the way the photo is taken, but man i want my echo that colour.

[tomacropod]

Roman, seriously what is with the lights in your basement? or is it just a screwed up setting on your graphics program? It's gay teletubby style

- Joel

[RomanR]

Haha, I wish those were my lights :p

I also wish I had that Echo control frame. The picture is from hbtrials.com, most of their silver frames (so, all but the caisso) have that certain pink glow.



Also, i just noticed i wrote 63 x 118 on my paint diagram. It's supposed to be 68 x 113.

[durkie]

so does anyone know anything about running 73x... bottom brackets in 68x... shells and vice versa? i hear talk of using spacers, switching out nondriveside cups, etc, but don't really know anything about it as far as durability or other issues.

[RomanR]

The raceface dh bb's are made for 73mm shells, but they come with a 2.5mm spacer that you put on the drive side cup to be able to use it in a 68mm shell. That's all you need for any 73mm shell bb; stick a 2.5mm spacer on it.

Now 68 in a 73, that's gonna bring your non drive side crank arm closer into the frame, and there aren't really any spacers you could use. If the 68mm shell bb doesn't have flanges on the cups, it will work, just thread both cups into the frame, and leave a couple of threads exposed from the bb shell. You just have to center it, but it's not a big deal.

For 68mm shell bb's, that have flanged cups, there is an option. I've heard of people that have bb's with plastic cups, that just filed the flange down, and threaded the cups farther into the bb shell. I don't know how good this idea is though.

[Poopslush]

I hate to bring up another old post but I thought it would be better than starting a whole new one. I was wondering if every bottom bracket on every bike (mod/stock) had the same internal diameter.

[Poopslush]

Shit, I would have edited my last post but it wouldn't let me. What bottom brackets do ya'll run (mod guys especially).

[Poopslush]

Right, well I've sifted through webcyclery for a while and this is what I came up with. http://www.webcyclery.com/product.php?productid=16397&cat=252&page=1
Would the right size to fit in my monty 219 be 68/73X107? Thanks.

[felix]

The axle might be a bit short. Measure the bb you're currently using and get one with the same dimensions.