I have a 2013 Jamis Coda Comp hybrid with 8-speed Acera/Altus groupset parts. I'd like to replace the whole drivetrain with 10-speed Tiagra. Is this doable? Anything I should be aware of?
Speaking just in terms of the mechanical aspects, it's usually fully doable. (The cost-effectiveness of such projects is often questionable at best, but it does depend.)
Potentially relevant ways that a hybrid frame can be different from a road frame of the sort those components would usually go on:
- Large chainring clearance, ie on some hybridy frames you'd find a larger chainring would run into the right chainstay. In this case it starts out with a 48, so not likely to be an issue. If any dealbreaker comes up with this kind of conversion, this is usually it.
- 135 rear spacing, not 130, putting the chainline out 2.5mm from what road cranks necessarily "expect." Usually this won't make a relevant difference, especially since chainstay length will be longer on a hybrid frame, which always mitigates some of the issues of suboptimal chainline. There are a lot of road disc bikes running around now with the same deal and it almost never makes any real difference, but there are some manufacturers (SRAM) that make a bunch of alternate spindle length road cranks for this reason.
- FD cable routing. Some hybrid frames have their housing stops set up for top pull, which no road FDs natively accomodate. A clamp on seat tube pulley is usually the fix if its needed. I don't believe any generations of Codas are like this though.
- FD barrel adjuster, or lack thereof. Road groups expect there to be one on the frame, which is usually not true of hybrid frames. The solution is to use an inline adjuster, which a lot of stock road bikes do now anyway.
As mentioned by @Nathan Knutson I would have thought that chain line would be a major consideration.
I assume as you have chosen Tiagra vs. a higher level mountain groupset such as Deore because you want slightly higher, more road oriented gearing. I believe what you have on the Coda Comp is a 48-36-26 crankset with 11-32 cassette. With Tiagra you can opt for 50-34 compact or 50-39-30 triple cranks; 11-25 cassette with the short cage derailleur or 11-32 or 34 with the long cage.
There are flat bar shifter/brake levers that work with Tiagra: SL-4700 or SL-4703 depending on 2x10 or 3x10. Those will work with your linear pull brakes.
From pictures of the 2013 Jamis Coda Comp I'm guessing it has a square taper bottom bracket, which the Tiagra cranks do not support. You'll need to swap the BB out for an external bearing Hollowtech one. I guess the Shimano BB-RS500 should just work with the crank.
I see the Coda Comp has bottom pull front derailleur cable routing so that will work with the Tiagra front derailleur.
Don't forget to replace all the shift housing, and budget for the special tools you'll need (crank puller, cartridge BB tool, external BB tool etc.)