mostro

I have been trying to resolve a problem with an Ultegra front derailleur, actuated by an SRAM x.7 trigger shifter. Are these compatible? SRAM says that while the rear shifter has a 1:1 ratio the *front* shifter is compatible with both SRAM and Shimano derailleurs?? Perhaps not Shimano road derailleurs?

I have them both mounted on a Salsa Las Cruces frame with a FSA Gossamer triple 30-39-53, for which the Ultegra seemed the only viable choice. The SRAM shifter is pulling alot of cable, making the FD "clunk" and move much further that it should... I can't help but think I've put together an unworkable system.:

If so, what's a good solution? New shifter? Smaller large chainring with a different front derailleur?

Thanks for any help you can give.

halfspeed

Yup.

Either. You'll either need a friction front shifter of any type or a Shimano DT or bar end shifter. Alternatively, you can go with a smaller large chainring and an ATB FD, but that will require that you downsize your middle ring too. You should have a 12T difference between the big and middle ring to avoid the derailleur rubbing the middle ring.

Sometimes you can push the specs, but things usually work better if specs match.

mostro

Thanks Halfspeed...what about the Shimano "flat bar" components? They are:

R443 triple FD, compatible with SL-R440-8 / ST-R224 shift lever, and R660 flat bar trigger shifter
or the
R773 triple FD, compatible with ??? (presumably same as above, made for flat bar setup)


Do these have the same "pull" as the SRAM x.7 trigger shifters?

halfspeed

I'm not familiar with those components, but I would suspect they are not compatible with the SRAM shifters. Shimano and SRAM use different ratios EXCEPT for those SRAM components specifically labeled as Shimano compatible. Also, Shimano road and MTB FDs are different (although the RDs are the same). Go figure.

mostro

I've just read this month-old thread and am now more confused than ever. This fellow seems to have had success running a 105 FD with an x.7 trig shifter:

https://www.bikeforums.net/showthread...ont+derailleur

Even if this didn't work, would it be possible to get a Shimano "flat-bar" R440 left-hand shifter and use it with the Ultegra FD?

OneTinSloth

yes.

Cyclist0383

I also use a 105 FD with a SRAM X7 shifter. I have had no problems. On another bike I use an LX FD with an X7 also with no problems.

SRAM FDs and FD shifters have the same pull ratio as Shimano shifters and FDs. SRAM RDs and rear shifters have a different pull ratio than Shimano RDs and RD shifters.

mostro

I must be doing something wrong... how is it that a 105 FD would work with an x.7 trig shifter, but an Ultegra fD wouldn't? Don't they have the same pull?

maddmaxx 

The flat bar shimano front derailleur will work with a x.7 "trigger" shifter because the shimano flat bar front derailleur has a mountain bike ratio. The road 105 or ultegra derailleurs can be made to work with a x.7 twist grip shifter because SRAM gives you 8 "clicks" for 3 gears on the left shifter. The length of the cable arm from the pivot to the cable attachment is different between road ane mountain bike derailleurs.

Cyclist0383

My 105 FD works just fine with a SRAM X7 trigger shifter. It is possible.

mostro

Thanks for all the replies. I went ahead and ordered a R443 triple derailleur since that's the only solution that doesn't require me to swap chainrings or shifters. That Ultegra unit prolly would have been kinda lonely anyway.

I see on the SRAM technical data sheet for the x.7 trigger shifters that there are two distinct columns for the front shifter, one that says "Front/Micro Adjust", while the other reads "Front/Index." This suggests two different varieties of x.7 front shifter? Maybe that's why they work for some and not for others. Either that or something particular to the 105 that allows it to work.

Cheers

OneTinSloth

yes. as mentioned earlier, one (micro adjust) is a grip shifter, with clicks close together (hence micro adjust) while the other (index) is the trigger shifter with 3 distinct positions for the derailleur. SRAM also makes the rocket and attack shifters, which are shimano compatible. i forget which is which, but one is grip and the other is trigger. i believe those are X-9/X-7 level in quality.

the 1:1 (SRAM-compatible) grip shifter will work with a road FD, on a double or a triple. the 1:1 (SRAM-compatible) trigger, will only work with a road FD on a double, and it'll be dodgy at best, because of the differences in pull between road and mountain front derailleurs.

Cyclist0383

Do you have a SRAM X7 trigger shifter and a triple, or is all this theory on your part? I have a SRAM X7 trigger shifter and a 105 FD which shifts just fine on a Shimano FC-M581 48T-36T-26T crank. I think you are giving out incorrect information.

OneTinSloth

for the record, i have X-9 shifting a deore FD on a cook bros. mountain triple. it's not a shimano/SRAM incompatability issue. it's a mountain/road compatability issue. this would be experience, not theory.

road FDs have a much more linear effort:movement ratio, and most MTB FDs have an eccentric pulley that helps minimize the shifting effort to move it the required distance to initiate a shift. shimano does this for MTB FDs because there is a lot more crap that builds up in shift housing, cable guides under BB shells, and in derailleur pivots that makes shifting much more difficult. in order to have the FD move easier, they had to also increase the pull on the shifter.

for their RDs, they make the top pulley axle slightly longer than it has to be so it can slide back and forth to assist the shift when cables get gunked up. SRAM's solution to this problem for the rear was to make their pull ratio 1:1, which keeps the shifting accurate longer with gunk buildup.

i'm guessing you got lucky with your setup, i have never seen that particular combination work well under any circumstance. you are most likely pushing that 105 FD to the outer limits of it's travel, which will eventually result in failure.

folks, the compatibility charts exist for a reason. read them, follow them and it'll save you a whole lot of money and headaches.

maddmaxx 

I have to agree with OneTinSloth on his statements. The only way I could picture a 105 triple working with a x.7 trigger would be to set it up perfectly for the middle chain ring and then let the limit stops "make it right" for the small and the large. Slack cable isn't so much of a problem on the small ring but the shift mechanism must be under a tremendous load on the big ring. If you search back through this forum you will find front derailleur problems being a constant thread of the drop bar to flat bar conversion. The shimano flat bar front derailleur family for road bikes exists for a reason and this is it.

Retro Grouch 

Well, there's this:

Right now in my basement I have two bikes that violate this rule just as they came equipped from the manufacturers. One is my daughter's Burley Rock & Roll tandem that has STX/RC flat bar shifters and a Sora front derailleur. The other is my wife's Specialized Crossroads Pro that has LX shifters and a Tiagra front derailleur. Both shift just fine and neither has required an unusual amount of tuneing.

Over the years I have worked on many bikes, mostly tandems, that have used various Shimano flat bar shifters coupled with various Shimano road front derailleurs. If anything, I've found them easier to set up than an STI triple.

I've never seen, much less worked on, a bike that used STI shifters coupled with a mountain bike front derailleur. I'm told that, for some reason, that combination doesn't work.

So far as saving money and headaches goes, if I were buying new parts I think that it would be stupid not to buy ones the manufacturer says will match. If I already owned some components, I'd definitely try to make them work before I spend any money on new stuff.