(I know this subject gets beaten to death here, but here goes anyway.)

I'm considering converting my Ultegra triple to an FSA or similar compact crank double. Motivation is simpler and easier shifting while keeping a low gear for hills. The middle gear ratios look OK for what I typically use. I won't miss a 53-11 or even 53-12 (except maybe downhill with tailwind pursued by a runaway truck). Reduced weight is a secondary nice-to-have. Frame is a '99 Trek OCLV.

I'd like to use as much of my current components as I can. Currently:

Ultegra triple shifter (bought new in '04, 2,000 miles on it)
Ultegra front derailuer (triple), braze-on mount (used, ?? miles)
Ultegra cartridge triple BB with the standard wide spindle, Octalink spline (used, ?? miles, feels smooth)

Rear derailuer is a long-throw triple and I can live without the big-big/small-small gear combinations. Current cranks and chainring are stock Ultegra triple.

I know most compact cranks are ISIS but I think I can locate an FSA Octalink set. Assuming I can, do I need to switch to a double BB as well? If I must, I may as well get a new ISIS BB as well.

The front derailuer may have to be lowered slightly to accomodate a slightly smaller big chainring. Do braze-on mounts have enough adjustment to do this? If not, I need to get a clamp-on derailluer as well and I may just stick with the triple and save my money.

Info that came with my shifter suggests it's OK on a double, the middle position can be used to feather the derailuer.

Suggestions?

Not sure why your changing from a triple setup to a double/Compact. You already have a multitude of gear ratios. The compact crankset isn't going to give you anything that you don't already have regarding gear combinations. It will probably provide some weight saving with the elimination of the middle chainring, shorter derailleur cages, and shorter chain. But I don't know if that is what you are after or if the net loss will be worth the expense.

Fortunately, the Ultegra STI levers are Double or Triple capable. So you will not have to change the levers/brake handles. That is an expense saved.

But the Front and rear derailleurs are Double or triple specific. The triples have longer cages. You will also have to adjust the chain length accordingly.

You should get the Bottom bracket that works best with the crank that you select. Don't let the bottom bracket decide which cranks to purchase. Pick the one that best suits your riding style.

I switched my wife's '04 Shimano 105 nine speed from double to a Compact crank. I purchased the crank and the associated ISIS bottom bracket and then just lowered the front derailleur a bit to accomodate the smaller diameter chainring. The braze on should have a slight oblong hole that allows upwards or downwards adjustments. The chain should be shortened slightly but I did not do that and have yet to experience any problems. Once she puts on some more miles on the new configuration, we will see if that needs to be revisited.

Not necesssarily on the derailers,and his triple stuff will work with a double...There is no compact crank that is compatible with his 118 octalink BB.

Based on my experience, the converson is unjustified. You will not get noticeably simpler shifting (Modern drivetrains work quite well) and the weight savings will be measured in expensive grams (Especially if you use a clamp-on rather than braze-on front derailleur - plus it'll look a mess).

On the other hand, if you'd said you're bending under peer pressure (Your riding buddies are razzing you because you have a triple) or you just think a compact crankset looks cool, then there would be ample justification. If this is the case then go for it - FSA carbon compact crankset (Use a 50 T outer chainiring and the brazer-on derailleur should be fine), a 'ti' ISIS bottom bracket, and a short cage Ultegra rear derailleur.

If you have a braze on tab on the frame,you cannot use a clamp on FD.There is no double compact cramk that is compatible with your 118BB. There are no octalink compacts you could stick on it,but the chainline will be wrong.The shifter does a double or triple .Use the granny and middle ring positions with the hi limit set appropriate for the double setup.

The triple front will probably shift a little better. The triple has closer together more evenly spaced gears that are sometimes more convenient. If you really want to do this for weight considerations go to the Shimano website first, get the average weights of the different parts, add them up and see where you are. Then decide. It may be not as much of a difference as you think. You will lose you lowest gears. If you want to compensate by using a larger casette the weight starts going back to were you were.

Thanks for all the responses. My primary motivation is simpler (in theory) shifting, maybe I just want to buy my bike something nice . If I was going to go weight weenie crazy, I'd be looking at retooling the entire drive train and wheels or better yet a new bike. Other than the BB swap (which I should learn how to do anyway) I can likely do all the work myself (built this bike up from parts and Ebay auctions last winter).

Gruppo: No peer pressure here - the local alleged "B" club ride drops me consistently in the first few miles, I can sort of catch up to the slowest if I hammer for the next 10 miles and the traffic and hills slow them down a bit Need to work on the "motor" more than the bike, I guess. The people I usually ride with are just happy we found the time to ride (e.g. or wives and children gave us a few hours off )

Sydney & others - if I do go this route, looks like I need to replace the BB to make it work. Which is what I wasn't sure about. Compacts may make more sense for the NEXT bike.

what cogs do you have in back?

Go with an Ultegra double (109.5) bottom bracket if you get the Octalink. Otherwise, an ISIS BB will be fine.

As for the braze-on derailleur, it's possible it won't adjust low enough. Mine didn't on my '03 5500. You have two choices - your Trek dealer can order a customized tab that will allow the der to go lower or you can file it out yourself. I filed mine with a rat tail file and it works great. PM me if you need info or pictures.

55/Rad

Oh God, here I go again....
The chain rings give you different speed ranges. You should be selecting one of these and stay in it until you run out of gears or are cross chaining. Then you change ranges by selecting a different chain ring. You should NOT be shifting the front very often at all. Just when you go from the flat to a hill or hill to the flat. In DC, you should be able to put it on the middle ring all day long and just shift the rear. That can take you from walking pace to about 24 mph with a nine speed rear. You can't get much simpler than that unless you go single speed.

You are not going to make anything simpler by going to a compact double. You will just be spending a lot of money to throw your big chain ring away.

I know this thread is more than 4 years old, but I don't care. I'm quite sure the idiotic mentality of *not* answering a poster's question has survived over the years.

This poster did not ask for anyone's philosophical opinion of whether swapping components was a "good idea". This poster asked for advice on how to ****ing do it. Note those words: "how to".

Whenever you see a poster that asks "how do I perform operation X", either answer them with instructions or SHUT THE **** UP. They do not need your mother****ing worthless opinions of whether or not you think it's a good idea or not. If they wanted to know that, they'd ask.

Cheers.

All of the OP's questions were answered correctly. He thanked the responders and made a good decision based on the advice offered. Your attitude and language are not appreciated. Go ride your bike.

Al

This is a LONG-TIME problem for internet forums. When a person asks *how* to do something, people should have the courtesy not to interject their opinions of whether or not it should be done in the first place. But since I have not and will never see that courtesy, I have joined the bandwagon of discourtesy. I just happen to do it by saying F*CK. And in my opinion, swearing is far less discourteous that the implicit wolf-in-sheep's clothing bull**** I formerly mentioned.

Thank you for not understanding.

What about the questions on how to do something that is a bad idea and dangerous? Who draws the line on what is a bad idea? What about someone who wants to know why something is done?


forum

1. the marketplace or public square of an ancient Roman city, the center of judicial and business affairs and a place of assembly for the people.


2. a court or tribunal: the forum of public opinion.


3. an assembly, meeting place, television program, etc.,
for the discussion of questions of public interest.


4. the Forum, the forum in the ancient city of Rome.

Correct but we do....The OP's question was answered. No reason to turn this into a pissing match.
Feel free to start your own thread on forum etiquette maybe in Foo.