Looking to build a bike with a Ritchey WCS 110 V Crankset.



Would like like to use an Ultegra level FD. Can I use any double Ultegra FD? Or must I use one that is specifically for a compact crank?

I just built up a road bike with a compact front double using a Campy Chorus CT front derailleur. The drivetrain is Shimano 10-speed. I used a Truvativ Compact 50-36 crank.

A compact FD is a better choice, as the radius of the cage will be slightly shorter to match the shorter radius of your largest chainwheel. You could probably get away with using a full-size FD, but full-size FDs have longer radii to accommodate 53t front chainwheels and will sit farther away from your crank on the back end if mounted to the proper height on the seat tube. That shouldn't affect shifting.

Front derailleurs have come in a standard radius for decades and have worked well on triple chainsets ranging from 22 to 54+ teeth. The new compact front derailleur is, well, marketing at it's best. They may, in the laboratory, provide something that resembles smoother shifting on smaller chainrings, but 999 out of a 1000 riders would not recognize this improvement on the road. They probably work best for riders who have little knowledge of the history of the derailleur. In addition, what if you want to use larger chainrings? OH OH Gotta buy a new derailluer.

So the answer is no, you do not need to buy a compact specific front derailleur.

FWIW, I use an FSA 50/36 (not a typo) with a Campy Record FD. While it has to be adjusted just right, it works fine. Before I made the switch to compact I called FSA (no waiting and a polite, knowledgeable person talked to me) and they said it would work with a 50/34 (no typo). FSA also covered this in the FAQ section of their website. You might try Ritchey's site or email them and see what they say.

You can use a standard double derailleur, but I've read a number of reports of the chain falling off the 34. It could probably be avoided by playing with the low limit screw, but I really like my FSA c-16 compact front derailleur as it's basically idiotproof and I had no trouble installing it myself.

FWIW, I use a standard 105 FD on my tourer that has a 48-36-26 front crank, and it shifts fine.

I use standard Ultegra double front derailleur with an FSA 50/34 crankset. I lowered it a few millimeters on the seat tube. Shifts just fine. The only thing that I had to buy when I converted my bike to a compact was the crankset.

A friend bought a Scattante with 10spd DA grouppo and 6 months later swapped out the crank/BB to FSA carbon compact, changing nothing else and has had no troubles so far with chain drop on the 34 tooth with the original DA FD. FWIW FSA sells a designated 'compact' 9-10spd FD for $25-30.
Steve

The limit adjustment won't fix that. You can buy a chain keeper that attaches to the seat tube and prevents of chain from going inside the small ring.

I use an FSA SLK 50/36 with an Ultegra regular FD and it works like a charm. I do have a chain keeper as described above and it has prevented the chain falling off the small ring completely.

Never had a problem with it, and we sell numerous bikes with a stock setup of a plain ole front derailleur and a compact crank. Marketing isn't your friend, proper adjustment is.

Thanks, a compact double crank will still need a double FD, right?

You are correct in saying that Standard Shimano double ft ders have a 14 tooth range. Most, not all, compact cranks have a 16 tooth range ie: 50-34=16 teeth. Most people who have used compact cranks with a standard der will tell you that standard double ft ders work but give less than satisfactory performance.

My advice would be to try the compact crank with your present der first. If it doesn't work well then try a compact ft der. No sense in spending money if you don't need to.

Tim

Couldn't tell you, though I don't see why a triple f. der. wouldn't work just fine.

reg will do fine...just lower it a bit and tune. I have two CC cranks and one has a reg and the other has a CC drl. There is no need for it...the reg works just fine. Hype.

take the time and read...https://www.bikeforums.net/road-cycling/123238-compact-crank-overload.html

there has been some who don't like the triple f. der. for the CC...and like you I can't say for myself.

But the cost of a f. der is low as it has been pointed out.

If the OP has a triple with a triple BB then moving to the crank that he has posted will not work unless he has a new BB to go with the double b/c the BB is too long.

OP...if that is your case then go for this....https://aebike.com/site/page.cfm?PageID=30&SKU=CR4234...

Thanks for the posts and links. I need to take a closer look at the FSA crank. You seem to to be way ahead of most when it comes to compact cranks. I think compact cranks are becoming more popular. On my present bike I don't use the 3rd chainring (smallest.) Also, using the compact crank could help solve some chainline issues on certain gearing choices while still providing adequate gear ranges. IMHO

A funny thing in all of this is that Rivendell Cycles really likes IRD's compact-specific front derailler, that nicely follows the curve of a slightly smaller large chainring (optimized for a 48t as opposed to a 53, I think). Now, Riv admittedly likes intentionally-designed form, and beauty as well, and IRD compact FD has these. But it's funny because Riv tends to set themselves up against marketing-hype of the bike industry. At least they admit there's no real functional advantage to it.

This is a spec sheet for an Ultegra front derailleur: https://bike.shimano.com/catalog/cycl...=1134355658514

It, and most standard front derailleurs, have a 15t capacity. Compact front derailleurs have a 16t capacity.


Seems like everyone on this thread is telling him that standard double ft ders work and give completely satisfactory performance.

So, I will have use a triple FD and adjust it to shift with the compact crank?

You could, but you don't have to. A 1t difference in capacity is pretty irrelevant. Those numbers are for reference. The other thing about triples is they have a ~22t capacity from big ring to small, say 52-30, but that's over three chainrings, not two. And triples have a suggested middle chainring capacity limit of ~12t between the large and middle. So, technically, a triples capacity from 1st to 2nd is less than a doubles capacity from 1st to 2nd, meaning you will probably get better performance from a double.

The standard double front derailleur works fine as long as it is adjusted properly, meaning set to the correct height in relation to the large chainring and angled properly in relation to the chain. Some posters above have given good advice on this. Most books on bike maintenance and probably the Park site have a front derailleur adjustment section to show how to do this.

The key is to set the front deraillleur as low as possible and to get the correct angle, which will probably be front slightly toed in, but that will come in the final adjustment.

Thanks! Time to make it work.

Are you moving from a 3 ring crank two ring crank?

If yes...Have you got a new bottom bracket for the two ring crankset?

If no...your two ring crank set will be too far from the frame and will impact your shifting and what cogs you can get to if you use the bb that came with the 3 ring crank.

so if you have to get that crank plus a new bb then cost wise the crank I gave you above sould be on the table.

You will use that big ring more. What cog set are you going to run it with?

Just make sure that your inner ring clears your chainstays if you go the route of reducing your bottom bracket spindle length. Some frames will not allow this kind of reduction.

A triple FD will work on a double. The reverse is not necessarily true, however. It depends on how small your granny gear is and that the back of the FD cage crossmember stays below the chain while the chain is on your lower gear combinations (like the granny in front and the third from innermost or so on the cassette)