Drivetrain for dedicated turbo trainer bike

[jadedaid]

I’m putting together a turbo trainer setup for the winter which will have a dedicated bike on it. My main bike is running etap but unfortunately won’t fit the trainer.

I’ve picked up friends old bike on the cheap cheap which fits my required touch points but came with (a fairly abused) Tiagra 4700 groupset. Did I mention it was cheap? :) My last two drivetrains were etap and di2 and in comparison this is very loud with horrid shifting action. By all accounts a well maintained Tiagra should be a good drive train so I’m surprised by how bad this is.

In light of that I would appreciate advice whether it makes sense to try resurrect a drive train which has been poorly maintained (given that it will only ever ride a turbo) or if I should replace it with something else - I would prefer a quiet drivetrain as the turbo will be set up in an apartment. I’m partial to SRAM so thought about doing a 1x conversion? I won’t need braking so mechanical/rim/disc is irrelevant...

Thank you in advance!

[unterhausen]

I have a smart trainer I use in erg mode, so this might not apply, but my drivetrain is even cheaper than yours and works fine. I even have downtube shifters in friction mode.

Trying to understand how the Tiagra is causing you problems. Chain, cassette, and chain rings are the things that matter on a trainer.

[sitzmark]

What is the "turbo trainer" you are building around - wheel on or wheel off?

You really only need 1x (large ring -> cassette) for a dedicated trainer - no need for extra low gearing. Does trainer have resistance adjustment or is all resistance coming from running gear ratio?

As for drivetrain noise, do you suspect it is from poorly tuned alignment or worn components (chain, cassette, chain ring)? You can forget about FD as a trainer-dedicated set up - if rubbing on chain just remove. If experiencing difficult RD shifting, might need cable/housing replacement (inexpensive). When shift cable is detached does parallelogram move smoothly? Is the der bent and binding? Is the cage bent? Is the hanger or dropout bent? All possible issues with an "abused" system.

[jadedaid]

What is the "turbo trainer" you are building around - wheel on or wheel off?

It’s a Tacx Neo 2 - I plan to only really run ERG mode for TR, so potentially could forego shifting altogether if there’s a reasonable way to set the chain length at what it needs to be?

I don’t like the look of the cassette, chain and the shifting throws on the shifters themselves are a bit off but the RD and mech seem to be in good shape!

[Iansir]

I run a kicker with an RD with limit screw adjusted to be in the 2nd smallest cog, no cable. Works great for erg mode.

[sitzmark]

It’s a Tacx Neo 2 - I plan to only really run ERG mode for TR, so potentially could forego shifting altogether if there’s a reasonable way to set the chain length at what it needs to be?

I don’t like the look of the cassette, chain and the shifting throws on the shifters themselves are a bit off but the RD and mech seem to be in good shape!

Least expensive first step would be to shift RD to a cog that makes best chain line and tune drive line for that combo. See if you can tune noise out. If not, install new chain and maybe a new cog for that configuration. Check pulley wheels for excessive wear. Keep RD as chain tensioner. If you want to retain rear shifting consider new cassette, cable, housing.

For permanent erg mode trainer all new driveline/shift group is unnecessary if you're goal is lowest cost.

[vqdriver]

I'd remove the drivetrain and clean/degrease the whole shebang and relube it. Then reinstall it as new parts with new cables. I wouldn't buy anything until this step.

[GregL]

I'd remove the drivetrain and clean/degrease the whole shebang and relube it. Then reinstall it as new parts with new cables. I wouldn't buy anything until this step.
^^^This^^^. And if it’s really well worn, think about replacing the wear parts (chain, cassette, and chainrings) as needed. A well tuned Tiagra group should be perfect for a trainer bike. My trainer/salty road bike is a mongrel with mixed Shimano parts that were leftovers from my parts bin. With fresh cables, it still runs like new.

Greg

[vqdriver]

I'll add that I go pretty far with the rd disassembly. You'd be surprised how far sand and grit can work their way in.

[jadedaid]

I'd remove the drivetrain and clean/degrease the whole shebang and relube it. Then reinstall it as new parts with new cables. I wouldn't buy anything until this step.

That sounds like a reasonable way forward to start off with. I’ll give that a try and see how I fare!

[wallymann]

xxx