Bicycle Mechanics - External bearing BB just had a hernia!

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.



PDA
BCRider
11-02-09, 08:49 PM
I noticed the other day that one of my two external cup BB and cranksets just had a hernia and some of the baby blue grease has gotten past the outer seal. Is this something that others have seen? It's the left side and occured at the outer edge of the face seal.

I love the high degree of stiffness and low weight of these one piece crank and external BB's but it sure seems like the seals are whimpy and exposed to a lot of side shearing forces from even careful installation. Mind you for all that the seal that went in this case isn't one that was disturbed at all as part of the install.

operator
11-02-09, 08:52 PM
There is nothing... to worry about.
Chris_W
11-03-09, 01:07 AM
BTW, your crankset is a two-piece, not a one-piece as you described (and the old-style ones are called three-piece). There are a few one-piece cranksets out there, used on some really cheap bikes and some BMX's, but I bet that you don't have one of those.

Soil_Sampler
11-03-09, 01:15 AM
There are a few one-piece cranksets out there, used on some really cheap bikes and some BMX's

expensive ones too...

http://www.bikerumor.com/wp-content/uploads/2008/10/look-carboncrank51.jpg
Metzinger
11-03-09, 01:16 AM
You should get a BB30 on there, pronto.
Chris_W
11-03-09, 07:11 AM
expensive ones too...

Thanks, I was also thinking about that Look crank when I wrote my comment, but decided not to complicate matters. I like to call that Look crank "one crank to rule them all" because it does everything - 110mm BCD and 130mm BCD, 170, 172.5, and 175mm crank arms, all in the same crank! That must drop production costs down from astronomical to merely insane.
well biked
11-03-09, 07:55 AM
I like to call that Look crank "one crack to rule them all"

I could definitely see that crank cracking.:D
davidad
11-03-09, 09:19 AM
The seals are dust seals and will allow a full compliment of grease to leak out until it'sw balanced.