Hi all
Up until recently I’ve been using my new bike on the trainer. But I’ve been concerned with potentially damaging it so I’ve slapped my old road bike on the trainer. I’ve been having a mind numbing time dialing everything in, and it got me wondering if this whole thing is worth the effort.
How many of you use your “A” bike on the trainer? Are you concerned with damaging things like the drive train with sweat or the rear axles is you’re in direct drive?
Always “A” bike. Never an issue. If trainers broke bikes as much as people worry about it’d be a daily meme online with snapped carbon or people falling off. We’re just not seeing it. Those we do are almost all user error (skewer not tight, etc).
https://www.reddit.com/r/bustedcarbon/ for some visual fun… 
Oh hey! Is this the same GPLama on YouTube? If so I love your videos man!
There’s only one of me… which is one more than some manufacturers would like. 
As to potential bike damage, there’s probably more chance or ruining things like handlebars, bearings, spokes and any other metal parts in the area from our sweat.
If left uncleaned, the salt from our sweat can lead to terrible corrosion that will ruin parts.
So, do your best to cool appropriately (and minimize sweat if possible), wipe up any sweat after rides, and keep an eye on everything over time.
Yes I recently purchased a sweat guard, but I need something to protect the drivetrain when the fan blows my sweat towards it. That and I need a second lasko fan.
Yep A bike on the trainer. If you are training for an event then good to have the bike you will ride on. I don’t go too nuts on standing sprints or anything like that and give it a good wipe and spray after the session. The sweat can drip down into you head tube and corrode your steerer bits and bobs.
FulI respect to Mr Lama whose advice above is probably right for 99.999% of riders. But I broke a Supersix that I really loved on the kickr 
. Failed at the chain stay in a seated sprint.
To be fair, it was a second-hand bike so maybe there was undisclosed crash damage… but for me it’s metal bikes only on the trainer.
I only have one road bike so it gets used on the trainer, I keep a towel on the bars and have one of those tacx top tube / stem protector things as well, I have a friend whose sweat almost ate right thru his bars, yikes!
I reckon you have to be putting out pretty significant amounts of non-carbon directional forces to snap a chain stay in a sprint. Non-disclosed defect for sure. Sorry that happened to you.
The answer is N+1 
I had been using my A bike on the trainer until I came up with a great justification to get a new bike this year. So my former A bike became my trainer bike.
However, for both the before and after scenario, @mcneese.chad suggestions are good ones that I follow: great fans (I use 3), plenty of towels for during the workout, and wipe afterwards.
I always use my “A bike”. To be more precise, I am using my A road bike (aka my only road bike) and let my mountain bike serve double duty as a commuter. If you have the luxury of space so that you can just keep your old bike and use that, why not. But you shouldn’t baby a bike, it’s been made for a purpose.
Definitely use my A bike. It’s all part of my plan to use the sh*t out of my A bike so I don’t feel guilty when I get the next A bike. 
“A” bike always which leads me then to A+1
I’m less worried about the frame than I am the components! I used to use my TT bike on the trainer, but no matter what I did and how hard I tried, I would always get sweat in the nooks and crannies of the cockpit. I didn’t fancy getting any siezed bolts in there so I stopped using it.
I have converted my winter bike to a trainer specific bike, and have no intentions of riding outside this winter. Zwift race season is almost here!!
Whilst it’s unlikely a bike will break on the trainer, and if it does it’ll more often than not be user error, many companies are hesitant with warranty for trainer use. Some specifically exclude trainer use. A big move forward is that all Specialized bikes from 2020 onwards will be “trainer friendly”. I hope the rest of the bike industry follows.
Ride On!!
Both my road bikes (Bianchi and Boardman) have warranties that cover, even encourage, trainer use. I can’t believe it’s taken a company as big as Specialized so long to catch up really!
I only have one, but I use my Trek Emonda on the Hammer direct drive and no problems with anything breaking, cracking, no problems with metal corrosion or BB90 problems, etc. I just wipe everything down after I finish a session. I messaged TREK customer service and they told me that trainer use does not void their warranty, so if anything ever happens I’ll just get a new bike.
The only time I’ve personally known someone who damaged their bike on a trainer is when my buddy was taking his bike off, fumbled and dropped it, and it cracked when it hit the Hammer trainer.
The trainer at home, I’ve a dedicated bike. An old 7 speed hack, with spacers. Set up as close as I can, given I’m not a fitter! I have the space to do it, and it definitely makes it easier.
I’ve been using my best bike on hybrid rollers as it has a power meter - different to a trainer, but main concern is sweat to be honest. Took advantage of a weak sterling, and a brother who lives in the channel islands (so no vat!) to get a power meter for the B/ Winter bike mainly for this tbh. (I swapped the crank last winter, but seemed easier!).
I have an older, retired road bike that I had on the trainer but find myself preferring to just leave the CX bike on there all year. I should note that although I own and ride a road bike, I only race CX. Also, my road bikes, CX bike, and mountain bikes have a ReTul video fit so the road and CX biks are identical so I can swap from each bike without a change in fit.
I use my B bike on the trainer because I don’t like the hassle of taking the bike on and off the trainer - not concerned about breaking of damaging my A bike, just can’t be bothered to swap the bike around