I have a question for those of you who have ridden both flat and drop bars on the same bike. When setting up drop bars, I'm considering two primary grip locations, flats and hoods. How has the distance from the saddle for these two points compared to where your mtb bars were? I'm guessing for most people the hoods will be further forward than the mtb grips were. I'm not sure if the flats will generally be closer than the mtb grips or about the same distance.

What has your experience been? I've got my mtb fit dialed in pretty well but want to get a ballpark idea of what I need for a stem before jumping into a drop bar conversion.

the frames for MTB have proportionately long top tubes..
reach to the hoods is going to be quite far and nothing you have is transferrable
stem, brakes lever and cables.. shifters ..

Consider Trekking Bars: the figure 8 bend will have the added hand positions ,
but retain the gear and shiftlevers as the tubing remains 7/8" .. 22.2mm

bar clamp in the center, so side reach is the same, front further, back closer..

bull horn setups (below) are just further away and lower. IDK if any parts are reusable.

^^ What fietsbob said.

But also, if you're not going to use the dropped part of the bar, you might consider bullhorn bars. Post pics of the conversion, whichever you decide to go with.

Both of my current bikes were designed for flat bars and I am using the drops. I'd want my flat bars to be where the brifters start (the rubber part). So stem is some 3-4 cms shorter compared to my flat bar setup. Saddle nose is about 5 cms higher than the top of the handlebar and I normally i ride in the drops but this might be irrelevant for you, everyone rides/likes it differently. Obviously i've got somewhat long trunk and arms.

If your bike fits you well now, it's going to be weird with drops unless you change the stem. My goal was to put the hoods in about the same position as the grips were on my flat bars (though not as far apart). This required a much shorter stem with a much steeper rise. The steeper rise was necessary to get the hoods at the right height. The shorter stem means you've got less distance to achieve the same height so the angle needs to be steeper. I hope that makes sense.

I ended up using some flared cyclocross bars that were wider than typical drops because I still wanted to be able to take the bike offroad now and then. I was pretty happy with the results. Getting the stem right was one challenge, the other was dealing with the front derailleur.

While rear Shimano derailleurs use the same cable pull regardless of whether they are meant for road bikes or mountain bikes, the same is not true of front derailleurs. So STIs won't work quite right with MTB front derailleurs. You can of course switch to a road derailleur but most of those are bottom pull and a lot of mountain bikes use top tube cable routing. You may run into cable pull issues depending on what brakes you have too.

What ended up working best for me is switching to Campy shifters, the type that feature ratcheted shifting on the front rather than indexed. This meant getting a shift-mate for the rear to compensate for the different pull. It was a fun project and I was happy with the results but there were a few challenges.

Sounds like an expensive proposition. Got any pics of your conversion tjspiel?

It went through a few iterations:

STI:


Campy:


IGH:


The STI conversion was the cheapest because I already had most of the parts laying around. I just needed a new stem, bars, and some misc parts. The front shifting was never quite right though. The switch to Campy sounds worse than it was. If you're patient you can find NOS or used Campy shifters at pretty good prices. Those shifters eventually ended up on another bike.

The IGH was by far the most expensive but since this was my winter bike it was worth it. Eventually I moved everything over to an aluminum frame because rust started show up around the canti-posts and other places. I tried to stay on top of it but I decided I'd rather not deal with it anymore. At that point I put the flat bars back on and gave it to my son to ride to school. A few weeks later it was stolen.

When I did my conversion, I kept the same stem, and didn't have any difficulty with reach.

Stem changes are pretty easy. I would worry about the rest of the conversion first, then figure out your stem last.

Older MTBs tended to have slack angles that "shorten" the top tube once you have the bike set up in more of a "road" configuration. The old rule of thumb is that each degree of changed seat tube or head tube angle works out to 1cm of top tube length, so if you ride a 73/73 road bike and attempt to set up a 70/72 MTB identically, you'll lose 4cm of top tube length from the MTB.

I had an old Bridgestone MB-1 at one time and put dirt drops on it and commuted a lot on it until I sold it. I now have an MB-6 with similar config. I swapped the long reach 130mm MTB stem at 107 deg (wasn't stock - I swapped it out due to long torso) to a 140 deg. high rise with just 100mm reach. Don't have before and after pics, but I think the riding position puts me slightly higher with the drops for the same reach. I imagine a line from the hub axle up to my eye. The old MTB flat bar and stem blocked the view, the new drop bar and stem still block it sort of, but is a bit more behind the hub, meaning I moved the bars slightly closer to me by a cm or so, but higher too. But reaching over to ride the hoods is extremely comfortable, and I could tour in this new position for a long time.

I put drops on my MTB commuter and put a shorter stem on, about an inch shorter. I didn't measure, since I just swapped for a spare I had hanging around. The old stem was fairly long and the new one is medium-long (maybe 4 inches?)

Before I swapped stems, the hoods were a bit far for comfort but the drops were fine. After the swap, I occasionally wish the drops were a bit further but the hoods are more comfortable. I have considered lowering everything a bit, and have plenty of stack (or stem angle flop) to do that with, but have generally been lazy.

I have a mtb I rode for years with what I thought was very good fit, and decided to build a road bike with drop bars, using fit on mtb as a design guide with a few tweaks.

Now that the road (touring, actually) bike is built and mostly fitted, I find the the ETT length + stem length is 7cm shorter than that of mtb, but the distance from saddle top center to normal hand position (on hoods on road bike) is within 1cm on the two bikes.

I'd need to lop off 7cm of stem length on the mtb to fit the same drop bar in place of flat bar, which is nearly impossible since I have only 11cm to start with. I'd need a very short, steep stem to make this work. I predict you'll need the same, something like this:

https://www.aebike.com/Dimension-Thre...8_p_26022.html

You may also need a short reach drop bar too, to match the reach with flat bar.

as a bar converter myself I still recommend N+1 instead

here's my beast which was actually quite comfortable and fast. I was lucky and had an adjustable stem. I eventually got a road bike.