deano16

I have an old Trek 7.2FX that I want to transition to a drop bar/road/gravel bike. My front and rear derailleurs really suck on this bike and thinking of just purchasing some new derailleurs and road shifters to put on the new handlebars. I am a novice @ bikes and before I go and buy this stuff I want a pro to give me some guidance. I don't care about weight of the bike, just looking to transition this hybrid I don't use to a drop bar bike to use on gravel trails.

I am planning on buying a new crankset, front and rear derailleurs and shifters/brakes. Do I need to buy new brakes as well? Will road bike components fit on my frame without issue? I'll probably have a local guy install them, just starting the process of purchasing and need some guidance.

Thank you in advance for the help.

David

Andrew R Stewart 

Trek has used different brake designs on their bike as the years go by. I assume by the "old" reference you have cable operated V brakes. Is this correct? If you have a newer model with hydraulic disks...

Mtb and road gear systems have some interchangeability and some less so combos. Rear cog count and crankset ring C-C specs are part of this challenge.

Then there's the body fit aspects and the change of posture with bars that run forward from the stem clamp VS sweeping back from that clamp point. How this effects the upper body and leg angles can be unexpected for the inexperienced. Generally with flat bats one sees an increased seat set back and with drop bars this set back can be a hard body angle to maintain for long for many.

But the proof is in the trying. Most of the customers who do this are only somewhat happy with the results and many reconsider the smarts of this conversion. Keep the old parts to reinstall later to sell off the hybrid when you want best fit and performance using drop bars. Andy

cpach

Double check the geometry of the frame before you do the conversion. Often, geometry and fit for flat bars differs from that with drop bars. I'd get an idea of what the numbers would be for a conventional drop bar bike that fits you and compare to see if this is worth the effort. You will likely get a better value selling the FX as is and buying a gravel bike.
Also, I'd recommend just going to the shop and having them spec out a quote with you rather than asking people on the internet.

The likely compatibility issue would be the brakes, which are probably linear pull. You can get cable pull adapters to use the existing brakes with standard drop bar levers, or use traditional cantilever brakes or mini linear pull brakes. Also there might be issues with some road cranks and possibly a 73 (vs 68) mm bottom bracket shell, although you should be able to run a square taper crankset with the right BB.

If you came into my shop and asked me this, I'd probably try to steer you to using bar end shifters (or Genevelle shifters) and long pull brake levers that would let you keep pretty much your entire existing drivetrain and brakes and use them with drop bars.

fishboat

Built up about a month ago. B-day present for my GF. Most importantly..it fits her. Gravel-ish bike with the right top tube length and will run 38-42mm road or gravel tires.

2007 Trek 7.5FX WSD. Previous owner never rode it..probably doesn't have 50 miles on it.

Ultegra 6503 3x9 shifters, Tektro 510 canti's, Koolstop pads, Tiagra front and rear derailleurs, OEM 3x crank, upgraded to 11x30 cassette. Shimano 324 SPD pedals. OEM saddle..we'll see how it rides. It'll probably get swapped out for a Brooks that fits her well. Gravelking Slicks 700x38mm. Fast bike!

My GF was delighted with her gift. She's been riding for years and knows what fits her and what 'comfort' feels like. Now that she has 300-ish miles on it, she thinks it's the "perfect bike".

The only real issue has been the front derailleur(specifically the chain line). I switched out the OEM (mountain bike) derailleur(50mm chain line spec to fit trekking type 48/36/26 crank) with a 4503 Tiagra(45mm chain line spec) to match the OEM Tiagra rear derailleur, and be compatible with the road shifters. With the original front derailleur being a top pull, and road derailleurs (Tiagra) being bottom pull, you'll need a small part to reverse the cable direction (Problem Solvers "Cross Clamp" or Origin 8 "U-Turn Adapter, OR8"). The limit screw will be turned all the way out.

The Tiagra front derailleur was setup per the typical process (be sure to build in an inline barrel adjuster when setting up the front derailleur cable) and initially seemed to work perfectly...all front and rear gear combos worked great. Front shifting is typical of any triple. The limit screw will be turned all the way out. After riding a few hours the gear combo of large front chain ring to small rear cog resulted in a slight chain rub on the inside of the front derailleur cage. This is due to the mismatch in chain line specs, the Tiagra derailleur is running beyond its design limits. This can be cured by either a slightly narrower (2mm?) bottom bracket spindle or by slightly bending the outer front derailleur cage outward with a needle nose pliers. 1-2mm should be enough.

The conversion isn't difficult. It'll take an hour or two for a shade tree mechanic. It may or may not cost some money, depending on your parts supply and/or preferences. I installed all new parts except for a pair of used Ultegra shifters. New cables, Koolstop pads, canti brakes, bars, tape...... All in it ran me about $300 over the cost of the bike. I got the bike for a very good price. It was worth is for me (my GF) as finding a top tube length that fits her has been an issue. This converted bike fits her basically the same as her Bianchi Impulso WSD road bike(in terms of reach), but has a much nicer gear train, higher stack, and can run up to 42mm tires. It's a fast, light weight bike. She LOVES it.

edit.. After doing more research, it appears I could have used a JTEK Engineering Shiftmate 7 and the original OEM derailleur in combination with the Ultegra shifters and all would be well. Maybe next time..