Bicycle Mechanics - ISIS and others v New design

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brundle_fly
09-08-06, 12:02 PM
A lot of half decent bikes now come with the external bottom brackets.Do you think this is the way to go,or do the older designs still prove to be more reliable
How is the longlivity compared to the others? I assume that using larger bearings closer to the crank arm(as with the external) will make them last longer?

capwater
09-08-06, 05:19 PM
It's all marketing hype, suppossedly catering to the "stiffer is better" crowd. Lots of folks mistakenly think external bearing BBs are "10 speed" and thus buy into the latest fancy gizmos.
Wogster
09-08-06, 06:06 PM
A lot of half decent bikes now come with the external bottom brackets.Do you think this is the way to go,or do the older designs still prove to be more reliable
How is the longlivity compared to the others? I assume that using larger bearings closer to the crank arm(as with the external) will make them last longer?

External bottom brackets were invented because they wanted to make the axle bigger on some designs, which meant smaller bearings, which would wear out faster. Some people say it makes things stiffer, some think it's a marketing scam to promote incompatability in bottom brackets, still other people say it's bling factor and the remaining folks don't give a rats right ear, about internal vs external. As for bearing size, most externals use a larger diameter axle, and the same size bearings as an internal.

It really comes down to the requirements of the crankset, if you want a specific crankset, and it requires a certain bottom bracket, use the one that is recommended, and don't worry about it.

xlntRider79
09-08-06, 06:24 PM
all I know is that external bottom bracket cranksets made the price of a shimano LX crank go from about $70 to about $160. I'm thinking about stocking up on octalink bottom brackets now, because in a few years I'll be forced to "upgrade" whether I want to or not.

Sounds like marketing genius to me. They convinced everybody with external headset bearings and internal bottom bracket bearings that they had it backwards: internal headset bearings and external bottom bracket bearings are the real way to go. Maybe we'll see external wheel bearings next...
oilman_15106
09-08-06, 07:26 PM
all I know is that external bottom bracket cranksets made the price of a shimano LX crank go from about $70 to about $160. I'm thinking about stocking up on octalink bottom brackets now, because in a few years I'll be forced to "upgrade" whether I want to or not.

Sounds like marketing genius to me. They convinced everybody with external headset bearings and internal bottom bracket bearings that they had it backwards: internal headset bearings and external bottom bracket bearings are the real way to go. Maybe we'll see external wheel bearings next...

Think you have hit on the issue. Mfgs. need to keep changing things to justify their technology. Compact cranksets which are all the rage have been around since the 1970s. 9 speed is not good enough. The list goes on. You might be right about salting away some octalink stuff.
MichaelW
09-09-06, 03:59 AM
Why is it that manufacturers can change their frame design to incorporate new standards for head tubes to fit integrated headsets but can't fit a larger diameter BB shell to accept a hollow spindle + large bearings.
Tandem eccentric BB shels are large enough for all the gubbins to fit inside and they have a larger weld area for fat Al tubes.