Bicycle Mechanics - Compact crank changeout techie questions

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brentley
05-12-08, 09:32 AM
I currently have a 2001 Trek 5200 (ultegra 6500) with the stock cranks.

I am thinking about upgrading to a newer compact double from Shimano. I found a very lightly used one locally that will save me 50% on the package (it includes a dura ace BB and Ultegra SL crankset).

I undertand that I will need to replace the bottom bracket assembly when I do this so I have some questions.

1. If I replace the BB in a carbon bike is refacing required?
2. Are there things that I need to think about as I am getting parts together for this?
3. Are there any trek specific issues to think about?
4. Is this a do it yourself or LBS job?
5. Anything else to keep in mind?

thanks
Brentley


bikeman715
05-12-08, 09:50 AM
if you want refacing done has your lbs do it . is there a problem in putting the BB set in ? there souldn't be . if you have the tools you can do it yourself .

capwater
05-12-08, 09:55 AM
Make sure you can drop your FD far enough to accomodate the compact crank. if I recall on that frame there is a bolt on hanger. Might have to deremel out the slot some to get the proper height.


brentley
05-12-08, 09:58 AM
If I understand you correctly then, refacing is not required?

If so then I can handle the rest fairly simply.

fosmith
05-12-08, 10:07 AM
don't worry about refacing.
the only Trek specific thing you need to keep in mind is the metal spacer thingy between the frame and driveside cup. it will save your frame if you drop the chain.

other than that, you will just need to lower your front derailleur and reset the cable tension and maybe adjust the stops.

ScrubJ
05-12-08, 08:00 PM
Don't forget to shorten or replace the chain.

aloysius
05-12-08, 10:48 PM
Make sure you can drop your FD far enough to accomodate the compact crank. if I recall on that frame there is a bolt on hanger. Might have to deremel out the slot some to get the proper height.

Ugg, braze-on FDs...