sprintfree

Im currently building up a surly long haul trucker from the frame and cant seem to find the answer to this quesiton. I have recently ordered a Dyna-Sys 3x10 crankset, dyna-sys chain, and 10speed cassette, and In order to use my Shimano 105 5703 STI shifters I would need to install a triple road front der. (shimano 105most likely) and not the dyna sys one. I really would appreciate any input as to if this would work or not as its driving me up a wall. I also need to know if this wold be a reliable setup as I will be riding across the country next year.

Thank you

HillRider

Can't help with the fd for certain but I agree the 105 road fd is the probably one you need. BTW, the new Dyna-Sys REAR derailleurs won't work with your 105 brifters. You will need a 9-speed version of any Shimano MTB rear derailleur.

cyclist2000

This is correct. but what gearing will you be using? My touring bike came with a10-speed 12-28 rear and 50-39-30 chainrings, it has 105 shifters, 105 FD and Ultegra RD. If you want to use something like a 12-34 cassette with a triple crankset then you will need a 9 speed mtb RD.

I put a 9 speed 771 RD on my touring bike last month, it shifts fine with the 105 shifters.

reptilezs

dyna sys is only compatible with dynasys

sprintfree

forgot to specify that the RD is a 9 speed shadow model. cassette is 10spd 11-34 and crank is 24-36-42 dyna-sys. what i really need to know is if a road FD would work with that crankset, this is so i can use my STI shifters

HillRider

Depending on where you are touring and how much of a load you plan to carry, that gearing won't be anywhere low enough for most tourists. Unless you are credit-card touring in the Great Plains or Florida you will at the very least want to swap the 30T granny out for a 26 or 24T replacement.

I see you did replace the road rd with a compatible MTB derailleur. Are you going to fit a larger big cog cassette?

Shimagnolo

I tried a road FD (Ultegra) triple with an XT crank with a 48T large ring and it sucked.
The cage was shaped for a 50T or larger, and was so long that it hit the chainstay unless I raised it above optimum position.
I replaced the FD with an IRD Alpina-D and it works great!
I can't say for sure how it will work with a 42T large ring, but there shouldn't be anything special about a DynaSys crank.

desertdork

The 105 triple FD is really designed for an 11-tooth minimum difference between the middle ring and large ring, optimally being 39t and 50t, respectively. This is because the inner plate of the FD cage needs to clear the middle ring when you shift onto the large ring. To gain the necessary clearance with your 6-tooth difference on your 42/36/24 crank would require mounting the FD very high above the large ring; this would encourage the chain to be thrown off the big ring during upshifts.

If using drop bars on a touring bike with those chainring differences, I'd opt for bar-end shifters and select a FD that's truly compatible with that crankset.

mechBgon

I wonder if sprintfree made a typo, since the normal chainring setup on an XT DynaSys mountain crankset would be 24-32-42, not 24-36-42.

desertdork

Likely so, and my prior post is inapplicable jabber.

Jeff Wills

Wait- you mean there's applicable jabber here?

cyclist2000

I was intending to switch to a larger cog but I decided to try just the 9 speed mountain RD first to see if it worked well with my 105 brifters and the current 10 speed cassette before buying the 11-34 cassette, if it didn't work well I would have just given up on the project but since it works, I will get the new cassette this winter if prices drop.

I have been able to do some hilly riding in SE Ohio but it was tough in the lowest gear and I normally like to stay in the next to low gear so I have a bailout. At the present time I work too much to go on any tours longer than a week.

I have thought about swapping out the granny for a 24 or 26 but I'm not sure how that will shift.