Joined: 25 Jul 2005Posts: 1466Location: on the lake
ok, i'm having trouble with this fucking bb. i ordered a nice dura ace track one, back ordered so a triple was sent, f that. take it in, get a cheaper square taper one, instal last night. the numbers on this one are the same as the one i took out, (68, 1.37 x 24, 118) yet the spline? axel? was a little longer, like 3/8 longer. think, think, think... fuck it i'll try it. its in, but now i have one problem, one concern.
the problem: the wider spline moves the front ring farther away from the frame and this screws with my chain line, i really need something narrow!
the concern: with a wider spline the cranks should have a higher probability of pedal strike correct?
so do i need to find a 109? is that the spline lenght? i swear i left the shop with a 109, but when i got home it says 118. it's only been 24 hours and i'm all ready jones-in for my track bike.
joeball
Posted: Fri Mar 24, 2006 9:35 am
Joined: 24 Jul 2005Posts: 6037Location: Ether
68mm refers to your BB shell width, 68mm is the typical English threaded road bike width 70mm is Italian threading road, and 73mm is English mtn bikes
1.37 x 24 refers to the English threading
118mm is your spindle length this length is what you need to vary to get your chainline where you want it.
I have found that with a square taper road double crank and the chainring in the outer position and a 120 mm track hub that a 107mm spindle gives almost perfect chainline.
107mm is typically the shortest spindle though I have a 103mm track one.
As for types of BB, the Shimano UN-73 is xt/ultegra quality and should last a very long time, below that in quality is UN-53 which is still a very good BB. The DuraAce BBs do not have as good a seal as the others since that results in less drag IIRC, so for a road application you might want better seals
lantius
Posted: Fri Mar 24, 2006 9:39 am
1337Joined: 22 Jul 2005Posts: 6705Location: right over
yeah, unless you are like me and running a mountain rear hub, a 118 bottom bracket is going to be too long for a good chainline.
sekai
Posted: Fri Mar 24, 2006 9:47 am
Joined: 25 Jul 2005Posts: 1466Location: on the lake
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Joined: 24 Jul 2005
Posts: 6037
Location: Ether
1337
Joined: 22 Jul 2005
Posts: 6705
Location: right over
