velo

So, what's this bottom bracket lingo? What does it mean when they say a bottom bracket is splined? What is it if it isn't splined? What's cartridge style mean? What is it if it isn't cartridge style?

Thanks,
velo

Retro Grouch 

Most older cranks (and some new ones) have a square hole where they slide onto the square bottom bracket spindle. Splined bottom brackets, insted of being square, have a star shaped spindle like a gear. The crank arms have to have a star shaped hole that matches perfectly.

Older bottom brackets (and some new ones) have several pieces and serviceable ball bearings. Cartridge bottom brackets have only two pieces - a cartridge which includes the bearings and spindle, and a bushing which just keeps the left side of the bottom bracket from rocking. Decent quality cartridge bottom brackets tend to be relatively trouble free, but they aren't serviceable so when they go bad you have to replace the whole enchalida.

Richard D

Note that there is more than one type of splined BB - Shimano (Octalink) and Isis are the most common and aren't compatible. In theory a splined spindle gives a better contact making the cranks feel 'stiffer'. To be honest I couldn't detect the difference in use...

sch

Splined BB have a larger diameter than Square taper
BB axles. Splined are hollow and hence a bit lighter, but since they are larger in diameter they are stiffer. As
Richard implies, sub pro level cyclists will never notice.
There are several different Square taper standards:
Campy's taper is slightly different from Shimano which
is different from TA. For the most part this is not a deal breaker and mixing BB axles and cranks will work. However ISIS is totally incompatible with Shimano, as
Shimano refused to license the Octalink. ISIS was mostly ATB but has filtered into a few high zoot road sets. Steve

Raiyn

Not true I made the switch and I can DEFINITELY tell.

sch

Well there are always the outliers and those with golden legs..... : )
Those of us who are more torque challenged will not. Steve

khuon

Actually I believe Shimano will license Octalink... I have an Octalink compatible crank mated to a Dura-Ace BB on my roadbike. The same crank is also available in ISIS format. The thing with ISIS is that it's an open standard and free whereas you have to pay for Shimano's license.

Also note that there are also different versions of Octalink which are incompatible with one another. And then to add to the confusion there's other types of crank-BB interfaces coming out now including the new Dura-Ace integrated BB patterned after the XTR system from last year which itself was an idea "borrowed" from Bullseye of old. Race Face has introduced a similar system called X-Drive.

Dutchy

I ride two bikes, one with the old style square BB and one with the new Octalink type, and can not tell the difference. Just another marketing gimmick to grab our cash.

CHEERS.

Mark

d_D

There is a use and a requirement for splined cranks as anyone who has rounded a square taper hole or broken an arm will tell you. Doesn't stop the marketing department from trying to market them to people that are better off with square taper though.

I go through isis bbs at least twice as fast as the cheap shimano square taper bbs. With the current bb shell diameter and big spindle there isn't enough space left for bearings with a decent life.
Until the diameter of the bb shell is increased I don't think splined bbs have a place on bikes that arn't having problems with square taper.

I can't feel the differnce between them either.