I have a dura-ace 7800 groupo, all except an FSA crankset that is a compact 50/34. I would like to switch to a dura-ace 7800 standard double crankset 53/39, is this possible without troubles? Cassette using now is a 12-25 105 cassette. Also can a outside baring 7800 BB be used on a 2004 Lemond Buenos Aires frame?
I use the search feature but this specifice question answer did not come up.

It is a simple change. You will need the new crank and compatible bb cups. Your frame is English/ISO threaded so installing the cups will be no problem.

You will have to raise your front derailleur to clear the larger big chainring and check to be sure your chain is still long enough to allow shifting into big-big. The increase in minimum chain length will be 2 half-links (1") and you may aleady have that much slack but be sure.

Would I be able to use a less expensive Shimano 105 172.5 53/39 5600/Shimano 105 FC-5750 crankset or does it have to be a 7800 to match the groupo?

You can use the 105 crankset no issues.

Both your idea's are ok, cranks don't care too much about which groupset they are used with as long as they are the same speed; but getting a 5750 crankset will be easier than a 5600 or 7800 crank, as they arn't made anymore, and you will be looking at old stock.

I would not mind running the compact crankset but the dura ace 7800 rear derailuer will not shift into and 11 or anything about a 26? So going with a standard crankset will give me the 18-22 mph average speed that I ride with will training.

Another cheaper option than replacing the whole crank is to simply swap out your chainrings. For $72 you can have a 52/38 double using FSA rings: https://www.universalcycles.com/shopp...7&category=641

As far as your last question, I don't quite understand what you are trying to ask. Can you rephrase it and add a grammar check?

All of these cranks are interchangable and you can use which ever you want. The 5600 is the "period" match to the 7800 but the 5750 will work just fine.

My current Dura-ace 7800 rear derailleur will not shift into and 11 or anything about a 26cassette ring. I had a LBS try to adjust it many times with no luck. So I am going with a standard 53/39 crankset. My training average speed is 18 to 22 mph and I need the low gear. Is this a problem with the 7800 rear derailleur, or is my LBS no competent to tune the derailleur in?

Your LBS is apparently incompetent. The problem could be the derailler itself, a cable tension adjustment, a limit screw adjustment, or the derailler hanger. Most likely the latter as it's often overlooked.

Correct. Dura Ace rear derailleurs routinely handle 11T cogs and are rated for a 27T largest cog and often work with larger ones. There is nothin inherent wrong with the Dura Ace so something else needs to be adjusted or aligned properly.

I was looking to change my compact gearing too. I like the idea of getting FSA chainrings for my Shimano crank, but they are only available in black (per Universal's website), and that would look like crap on a polished crankset. Can I change out my Shimano 105 Crank for another option... like SRAM?

Also can a outside baring 7800 BB be used on a 2004 Lemond Buenos Aires frame? <--- since nobody has answer this one I'll answer it partially, eventually yes, u can use whatever cups in that frame as long are the same thread than the frame, i guess that frame is english threaded, on the other hand and this is the part i dont know, who knows if those external cups u want to use are compatible with other lower group cranksets. Maybe they are, maybe somebody can answer this better, im a campy guy. As for the cassette with 11 problem u have, I agree, the guys doesnt know what are they doing, to basic adjustment for them to do not figure it out.

Good luck.

@F75 Rider, swapping out the crank is easy and there's nothing preventing you from using a SRAM crank on an otherwise Shimano-equipped bike. Just order a new set of bottom bracket cups to match the new crank.

Assuming you wanted to keep the crankset though, Stronglight makes silver rings with a 110 BCD in standard double tooth counts:

https://www.xxcycle.com/110-ct2-outer...-speed,,en.php
https://www.xxcycle.com/110-ct2-2-10-11-speed,,en.php

Definitely more expensive though (over $100/pair before shipping).

Actually, I did answer this question explicitely in the second posting of this thread. His frame is English threaded and if he buys English threaded cups he can use any external bearing set he wishes.

joejack951, thanks for the info. The 105 crankset is on the heavy side, so it would be a good time for an upgrade. I prefer the look of SRAM over the Ultegra or Dura-Ace, and it looks like some nice weight savings can be found with the swap too. If I purchase a SRAM crank with bottom bracket & bearings, will I still need new cups?

Im a 951 fan too, have an '86.

The bottom bracket cups will come with the bearings already installed. So you'll be good to go.

Cool! Same year as mine. I've owned it since 1998 though I don't use it much these days. Are you by any chance on Rennlist?

Thanks again for the info on the crank swap!

I have used Rennlist, its a great forum. Havent really checking it out in a while. I went through some major issues with a motor rebuild on my 951 from a shop in San Diego.... what a mess (on Rennlist). During the time my car was in the shop, I picked up a 968 (still my daily driver).