I am thinking about throwing some flat bars on a cross bike for riding local trail trails with the wife. It's got a 9 sp 11-25 cassette, 105 short cage RD and a Tiagra FD. I know that using trigger shifters with the FD may be problematic. I was looking for a decent set of Deore shifters on e-bay. Anything I should look out for? Any 9 sp Shimano shifters that won't work? I don't want to buy a bunch of stuff only to find out it won't be compatible.

... or, I could throw on a 10 sp cassette and use SLX or XT 10 sp triggers? I've got a 105 10 sp cassette laying around and that might end up being easier.

Pauls thumbies, will let you mount Shimano's 9 speed bar end shifter
onto the handlebar .
index right with friction mode option, friction left
for FD trimming as the rear shifting changes angle
as it moves from high to low ..
and compatible with all FD's

This has been covered many times, but, yes, the front derailleur is the issue. The left-side flat-bar shifters are identical to the Deore (and SLX and XT) internally, so pick one and go with it.

What you need is a front derailleur that will work with the longer cable pull of the flat-bar/mountain left shifter and be contoured to work with the larger chainrings on your bike. That's the Shimano FD-R453 derailleur, available through knowledgeable bike shops anywhere: https://sheldonbrown.com/harris/derailers-front.html#352

I've been using this derailleur for years on my recumbents equipped with Deore and flat-bar shifters and "road" cranksets. It works perfectly.

Trek FX or something similar is my suggestion. You could probably sell your cross bike, buy a new FX, and still come out money ahead. Then the geometry would make more sense too.

You'd need to get a 10 speed MTB rear derailleur too for that to work.
A thread about compatibility: https://forums.mtbr.com/drivetrain-sh...ms-646014.html

Shimano Flat Bar Road Parts:
https://cycle.shimano-eu.com/publish/...andlebar0.html
https://www.shimano.com.au/publish/co...andlebar.html#

A possible option, but Nix that. Monkey-wrenching bikes is more fun. Having a frankenbike in the stable is more cool.

Hi everyone,

First time poster. I converted my Opus road bike this weekend. Its a triple with a 105 RD and Tiagra FD. I used the Shimano flat bar shifters and some Tektro levers - keeping the original Tiagra FD. The FD flat bar shifter has a "trim" feature and I haven't had any problems with shifting yet. Here's a pic:

The Tiagra front derailleur seems to be a little more adaptable than 105 and Ultegra. I've heard of a couple instances where it worked. I've also heard of a few where the 105 and Ultegra didn't allow the shifts to happen because the derailleur hit its stop before the shifter "caught". I'm still in favor of the right derailleur for the right application- here's a couple that are in my garage:

https://home.comcast.net/~jeff_wills/...-grr%20008.htm


and
https://home.comcast.net/~jeff_wills/...-grr%20006.htm

I found a set of straight bars, SLR-660 shifters, grips, levers, and a step for $50 on e-bay. It was a great deal and may solve my issue. There's not a lot of stuff about the R660 shifters, but they seem to be the (Ultegra) 9sp shifters that predated the current R770 flat bar shifters. If I can get the FD to work like crowly84 did then I should be all set!

Worst case I could go to 10sp and pick up the 770 shifters or maybe even try SRAM stuff since they seem to have more flat bar shifters available that will work with their road components. Next time I'll just buy a flat bar road bike. I have somehow convinced myself that I could only ride drops and that I loved riding the hoods. I'm looking forward to trying out this new setup.

In the worst case you can sell the shifters to me. Wish you luck with the Tiagra derailleur- but if you find that the shifter won't "click" once it's made the shift to the big chainring, that's a symptom of the shifter pulling too much cable. The solution is the FD-R453 derailleur, as above.

I may take you up on it or look for a good deal on that derailleur. If not I'll probably just go with SRAM since that may be cheaper than going to 770's with a new fd.

Put everything together today... works great. Tiagra FD works fine with the 660 shifters. Maybe if I was running 3 rings up front this would have been more of an issue?

The bike is pictured here. It's a Motobecane cross bike with flat Bontrager bars and 660 shifters. I put the bars on today and rode it around the neighborhood. It feels great and I can't wait to get it to the trails. Thanks for everyone's help!

Yep. But if it works, it works. I avoid getting working machinery mad at me.