Curious what you think. Should I put my Trek FX3 or Domane Al4 on the trainer? I prefer the FX3 for outdoor riding it’s more comfortable, but don’t want to trash the Domane with sweat. What do you recommend?
I prefer a bike with a more upright geometry for my trainer bike.
Aero doesn’t matter on a trainer.
Sweat is a problem for any bike you use.
I use a old second hand “Frankenstein” bike as a dedicated trainer bike.
So my answer is neither. You need n+1.
Two very different bikes for different kinds of riding. If you’re going to want to get racey at any point, the Domane is likely the way to go. Dropbars will (likely) allow you to sprint a little better for example (at least most folks I know like to get hunched over, hands on the drops for sprinting). It’s entirely possible to sprint on an FX–they’re a ‘fitness bike’ sort of geometry. And you don’t have to worry about wind and being aero, so the drop bars on the Domane won’t help with that. But the Domane will get you into a more aggressive posture that for many people helps them increase power. Definitely a YMMV situation though.
EDIT: But Tim’s N+1 answer is clearly the best answer.
I would also add that the gear ratio, assuming they are different, might play into your decision. I would guess the chain ring on the domane is larger, so you might want to use that one. You can get those sweat protector g string things for the bike if you are worried about that, or a product like ridewrap stickers.
Domane should be a 50t for the big ring, compact. FX3 these days is a 1x and…I want to say 42t. Older models would be a 2x, I think 48t big ring. FX will also have a larger spread on the cassette, much better climbing gear than the Domane. (Our shop is primarily Trek )
For most people, I doubt if 42-11 is something they can max out. But there are watt monsters on Zwift
For a trainer bike, before putting it on the trainer, I would strip it down, clean it up and clear coat everything including forks,stem and handlebars, if these items are metal.
I would lose the front derailer due to sweat.
I learned that non ferrus metals won’t rust but they corrode.
Don’t underestimate the damage and wear from your sweat.