Drop Bar Conversions

So I've got a drop bar Mukluk. It's awesome. Here's what you need to know in order to successfully do a drop bar conversion:

Geometry

This step is really important, because it will determine if the end result will fit you. It would really suck to finish the rather expensive conversion and have a bike that was too big!

The geometry of the bike will change. While flat handlebars are, well, flat, drop bars have significant extra reach associated with them. The Salsa Cowchipper has a reach of 68mm, and the Woodchipper has a reach of 56mm. The Salsa Rustler handlebars that came stock on my Mukluk had a 11 degree backsweep, which worked out to roughly -20mm of reach when I measured it.

So, we're talking a total reach difference of 88mm. The stock stem on the Mukluk is 60mm, and you can get 30mm BMX stems, which gets us to a 58mm difference. What I found is that your lower back angle doesn't change as much as you might expect due to the narrower bars. If we do a bit of geometry, we can make a set of triangles:

- Seat + Left Shoulder + Right Shoulder

- Seat + Left Shoulder + Left Handlebar

- Seat + Right Shoulder + Right Handlebar

We keep the body segment lengths the same - after all, your body can't grow/stretch all that much. When we move the handlebar grips closer, this gives you a more upright posture. So, when we move the handlebars forward and closer, we cancel out some of that forward lean. My calculations indicated that I was leaned over 1.5 degrees further with drop bars than with flat bars.

Let's compare the Salsa Cutthroat's geometry with the Mukluk. The Medium Cutthroat has a reach of 375mm, a 90mm stock stem, and handlebars with 68mm reach (Cowchippers), for a total reach of 533mm. My Mukluk's geometry has a reach of 428mm stock, with a 60mm stem, and -20mm reach from the handlebars for a total of 468mm. If we throw on the Cowchippers, then we have a new reach of (428+60+68) 556mm.

Putting a 30mm stem gets us back to 526mm reach, which is quite comparable with the Cutthroat's 533mm. The Woodchipper handlebars would reduce reach by another 11mm, for 522mm.

Once you've figured out whether or not the bike will fit after the new handlebars, it is time to talk components.

Components

What shifters are you going to run? This choice determines everything else about your build. It is common for road handlebars to combine shifting and braking, so the shifters you choose may determine what brakes you can run too.

You can run brake-only road levers with bar-end shifters. I don't recommend this - mountain biking often involves sharper steering, and I have found that the drop bars can interfere with my knees. Extending the drops further will only make that problem worse. 

SRAM makes a good choice here, as their road shifters are compatible with their mountain derailleurs. So you can continue to run a wide range cassette and have excellent shifting performance from road levers. SRAM just released a 12 speed road shifter, so if you're using an Eagle groupset, you'll be able to do that with road shifters if you're willing to pay the extraordinary price.

SRAM's Apex 1 groupset does not have a left shifter. This is good if you want a dedicated 1x setup, but you can use the left shifter to operate a dropper post, so you may want to consider a groupset with a left shifter.

Recent (10+ speed) Shimano road/mountain components are not compatible, though you can use a Wolf Tooth Tanpan to bridge this gap.

Shimano's Di2 system is compatible, so you can use Di2 Ultegra shifters to control a Di2 XT rear derailleur. This setup is extremely expensive.

SRAM and Shimano hydraulic brakes are compatible between road and mountain levers. If you already have SRAM hydraulic brakes, then you may want to stick with SRAM hydraulic brifters. It is likely cheaper to purchase a new rear derailleur than new brake calipers.

You can get TRP Hylex road hydraulic brake levers/calipers, and use Di2 buttons for shifting. This is a highly customized build, though I have seen a Trail Donkey from Rodeo Labs with this setup and it is clean.

Mechanical disk brakes are an option that will be cheaper and lighter, though they won't perform quite as well.

For my setup, I was able to snag a set of previous generation Ultegra 11sp hydraulic brakes and shifters for about $350. I was pretty happy with my SLX rear derailleur, and the shifting has been great with a Wolf Tooth Tanpan connecting them. The Mukluk comes stock with SRAM brakes. I could have gone for an Apex 1 shifter set and reuse the brakes, but then I would need to buy a new derailleur. Ultimately, I prefer Shimano components and shifting.

The overall purchase list looks something like this:

• $50-75 Handlebars
• $200-300 Brifters (pick SRAM or Shimano)
• ($100-150) Brake calipers (if current brake calipers are not compatible with new levers)
• ($70-120) Derailleurs (if current derailleurs are not compatible)
• ($40) WolfTooth Tanpan, if Shimano

The cheapest possible setup is if you've got a SRAM rear derailleur and SRAM brakes. Then you can get running with the bars and brifters and be set.