I have a hybrid bike which has dropped handlebars with Shimano Tiagra dual brake/gear levers. The front mech is a Tiagra triple ring and the back mech is Shimano Deore XT (9 sprockets) I have developed back problems and now need a more upright position when riding and am hoping to convert my bike to a flatbar. Can anyone help in identifying the options for compatible Gear Shifters. Thanks in advance
As long as your choosing a 9 speed Shimano shifter for the rear and triple shifter for the front you'll be fine. That's basically everything in the Deore lineup, as long as it's 9 speed. Obviously you'll want to stay away from 10 speed shifters and dont try to mix and match Shimano derailleurs and SRAM shifters or vice versa.
Though you didn't ask this, what may be a more important concern is how your bike is going to fit when you slap flat bars on it. Road bike frames are shorter in the effective top tube than mountain bikes are due to the fact that a straight handlebar decreases reach compared to a drop bar. Your bike is going to fit pretty darned short if you do a flat bar conversion which can cause comfort problems of it's own. There are other fit issues to be considered when doing a flat bar conversion on a road bike, but in my opinion this is the big one.
Before you rush to spend money on different bars and different shifters, have you ever considered a shorter stem? Perhaps a photo of your current bars/stem, and/or an actual measurement of your stem would help me to be more specific. You should measure it center-to-center, as shown in the illustration (3).
What I've found is that I get back pain when I'm too stretched out. That is, when the reach is too much for me, I get back pain. You can see the measurement I'm referring to in the picture below.
It doesn't take much of a change in the stem length to make a difference. Long story short, I changed my saddle and my bars, and started getting horrible back pain after 40 miles or so. I shortened my stem by 30 mm, and all is well. I can ride 70 miles or more before I start feeling any pains, but back pain is not one of them, typically.
If you can't post pics of your bike, measurements would be helpful for you to know. In addition, check your bike vs. a fit calculator like this one. Make sure you're in the range of numbers before you start throwing money at this problem.
Nine speed Shimano mountain bike shifters are usually (maybe always) compatible with Shimano derailleurs. I've definitely mismatched them in a variety of configurations and never had a problem. Stick with Shimano and you should be fine.