Am I stuck with this BB?
01-06-06 | 09:00 PM
#1
Thread Starter
Frozen in carbonite
Joined: Oct 2004
Posts: 805
Likes: 0
From: Ottawa
Bikes: '85 Full Cycle Cycle.
Am I stuck with this BB?
I found a great candidate for a fixed conversion in the trash a few weeks ago. The catch is it has a Mavic bottom bracket. After a search, I found this thread.
Does this mean that the threads of the BB have been completely buggered already and that I'm stuck using Mavic BBs until I find another frame?
It rotates mostly smoothly but there is a little bit of a rough bit. I don't have access to any tools until Tuesday so I can't even take off the cranks to get a look at the inside.
Any help would be appreciated.
"One word of caution with MAVIC bottom bracket. It does not thread into the bottom bracket shell. The shell faces must be chamfered to match the bevel on the inside of the adjustable lockrings that are used on both ends. The locknuts hold the unit in place laterally, providing some adjustment to the chainline, while the bevel ensures concentricity with the shell. MAVIC sold a special tool to chamfer the shell which may be hard to find, unless there is a LBS that used to carry the bottom brackets. However, any machine shop should be able to do this after measuring the bevel on the locknuts."
It rotates mostly smoothly but there is a little bit of a rough bit. I don't have access to any tools until Tuesday so I can't even take off the cranks to get a look at the inside.
Any help would be appreciated.
01-06-06 | 09:28 PM
#2
Junior Member
Joined: Sep 2004
Posts: 16
Likes: 1
You can use this threadless BB from www.biketoolsetc.com :
01-07-06 | 10:04 AM
#3
Senior Member
Joined: Aug 2005
Posts: 33,657
Likes: 1,119
From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
The only way to tell if the bb threads are usable is to remove the Mavic and try threaded cups in both sides. However, the Mavic was usually installed to allow use of a trashed bb shell so I don't hold much hope.
Assuming the original bb was English threaded, another salvage technique is to ream the bb shell oversize and rethread it to Italian threads, which are a bit larger in diameter. However, this isn't cheap and is typically used to save a valuable frame, not a dumpster refugee.
Assuming the original bb was English threaded, another salvage technique is to ream the bb shell oversize and rethread it to Italian threads, which are a bit larger in diameter. However, this isn't cheap and is typically used to save a valuable frame, not a dumpster refugee.
02-21-07 | 12:11 PM
#4
Newbie
Joined: Dec 2005
Posts: 2
Likes: 0
Mavic BB installation & use
The Mavic BB installation bevel is 45°, cut 2mm into the BB shell on each side. In a pinch it could be installed for light use without that but that would surely damage the angled face of the inside of the lock ring as well as risk the unit's movement under pedalling force. After a Mavic BB is removed, and the threads are intact, another traditional BB can be installed with very little issue.
The Mavic BB unit installs inside of existing BB threadings and was a fine option for an otherwise useful frame with threads damaged beyond the repair of a retapping, usually aluminum threads stripped out by overzealous BB cup installation (which side is left hand threaded?).
ASC in Pgh
The Mavic BB unit installs inside of existing BB threadings and was a fine option for an otherwise useful frame with threads damaged beyond the repair of a retapping, usually aluminum threads stripped out by overzealous BB cup installation (which side is left hand threaded?).
ASC in Pgh
02-21-07 | 12:37 PM
#5
Elitist Troglodyte
Joined: Jun 2006
Posts: 6,926
Likes: 3
From: Dallas
Bikes: 03 Raleigh Professional (steel)
Originally Posted by Grimlock
Does this mean ... that I'm stuck using Mavic BBs until I find another frame?
So ride the sucker and quit whining!
__________________
Stupidity got us into this mess - why can't it get us out?
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Stupidity got us into this mess - why can't it get us out?
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02-21-07 | 03:50 PM
#6
*
Joined: Jan 2007
Posts: 3,458
Likes: 2
Originally Posted by igor441
You can use this threadless BB from www.biketoolsetc.com :
$17 + shipping
