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C40 bottom bracket install question?(7 posts)

C40 bottom bracket install question?EV2
Nov 29, 2003 7:40 PM
I would like to ask questions in BB installation in a C40.
I'm going to use a DURA ACE 9spd BB which is not a sealed cartrigde type like the Ultegra or Campy.I know that the BB should be face to use the DURA ACE BB,but can or should the C40's BB be faced?since it's made titanium BB sleeve with teeths locking in the notches on the carbon shell lug.Would it weaken anything.
What do you use on the titanium BB threads? Grease? Anti-seize?
Would you use torque as recommended,or lesser to tighten the BB,since cracking the BB carbon lug can be very,very expensive.
re: Suggest you take it to a Colnago dealerhudsonite
Nov 29, 2003 7:56 PM
I have installed bottom brackets and they are typically never a problem. However, the Colnago's are known to require dealer prep before installation. This requires a minimum of a chasing of the threads. As to whether it requires facing, I doubt it, but then again I do not have personal experience with Colnago's.

I use high quality synthetic grease when screwing most things together, including titanium and never had a problem.

As a rule, I use a high quality torque wrench and torque to 70% of the recommend torque first, then move it up to 80% and then to 95%. I like to do it in steps to know where I am. I have screwed up before by using the wrong scale (lbs/feet instead of Newton meters I think). By doing it in stages, I have less chance of messing up. I try to stay just below maximum torque, but never more than 10% below.

My suggestion is to take the frame to a Colnago dealer and let them do the prep work on the BB. It will cost less than $100 and they take the responsibility. If they were to crack the frame, it is their problem, not yours. If you cannot afford to screwup, then you cannot afford to do it, im my opinion.
Additional post for above question /EV2....EV2
Nov 29, 2003 11:40 PM
Regarding torque of BB,You can't use a torque wrench on a Dura Ace 9spd BB,only a specific Dura Ace/XTR BB open wrench which I have and use on aluminum frames,it's kind of hard to estimate torque.Anybody out there have the same setup?
Additional post for above question /EV2....hudsonite
Nov 30, 2003 5:39 AM
I normally use Campagnollo and can easily use a torque wrench. Personally, I cannot speak to the issue of installing the DA BB.
No, you can use a torque wrenchTJeanloz
Dec 1, 2003 2:09 PM
There is a park tool that fits the splines for the DA7700 bottom bracket and will go on a torque wrench, I think it's the BBT2.
re: C40 bottom bracket install question?rogue_CT1
Nov 30, 2003 5:29 AM
The threads must be faced by an authorized Colnago dealer or it will void the warranty. The BB does not need to be faced. You really can't use a torque wrench on a DA BB. You install, tighten until the spindle doesn't move easily then back it off slightly until the spindle moves freely. Then install the lockring on the non-drive side. As with all titanium and aluminum contact point you need to use anti-seize. The Al tends to bond to the Ti.

Wherever you bought the frame probably didn't let it out the door without chasing the threads so you are more than likely ready to go.
never faced mine...C-40
Nov 30, 2003 7:37 AM
I've owned two C-40 frames and never did anything but carefully scrape the paint off the right-hand face of the BB shell and wipe the threads with acetone to remove a bit of paint overspray. I've used both Campy and FSA ISIS bottom brackets with no problem. Apparently the DA BB with it's needle bearings is sensistive to mislignment, so facing the BB shell couldn't hurt. Can't imagine why an authorized dealer would need to do the job. If done properly, only a few thousandth's of an inch are carefully removed from the face.

Both of my frames had aluminum BB shells, not Ti.
I would use anti-sieze anytime aluminum and Ti parts are screwed together, although a good grease may also be sufficient. There is no reason to torque the BB differently than recommended. You're not going to crack the BB lug during normal tightening.

Might not hurt to call Trialtir and get their opinion on the subject. Personally, I think it's a crime to send a very expensive frame out to a dealer that requires additional work to get it ready to assemble.