One bike or two? (trainer only bike/outdoor only bike) feedback appreciated

Hello, I was looking for some feedback and suggestions from the TR family.
I am currently doing my indoor training on a dumb trainer, and an older Cannondale (CAAD3 I think R900).
My outdoor bike is a 2015 (I think) Cervelo S3.
My thought was to preserve my nicer bike.
I ride indoors about 3-4 times a week and outdoors once a week, on the weekends, from mide March to end of Sept.
I thought it would be more convenient as I didn’t need to switch out the rear tire on the S3 to ride indoors and then also if I had not recently washed my S3 I would reduce the wear and tear by not riding on a dirty bike.
I have not had any fit issues although I am sure the geometry is not the exact same.
I was thinking about putting a bit of money into the cannondale to make the bikes more similar in fit (e.g. new stem, bars, and I will need an adapter as the head tube is more narrow I think).
However, I also started to think this may just be wasting my money and instead use my Cervelo for both in and out-doors (using a second rear wheel with a trainer tire on it).

Not sure this matters but my hope is within a year to get a smart trainer.

Thank you for any feedback, suggestions, things to consider, pros and cons of each arrangement.

I think it’s a good idea: having a bike ready on the trainer is always helpful if for no other reason than to remove a big obstacle to training.

I wouldn’t put money into the trainer fit if it’s not bothering you now. No reason for the two fits to be the same IMO—my trainer fit is significantly more relaxed/comfortable than my road fit and that’s fine. I know a lot of folks try to match fits, but I also know a lot who intentionally keep them different.


I’d happily have a more relaxed trainer bike.

Some suggest raising the front wheel slightly if use your road fit on trainers, as you do not have the wind resistance pushing and therefore more weight on hands.

On the road you and the bike move around more which helps with comfort. Add on cornering, frequently changing loads on legs and, if in a group, the opportunity to sit up out of wind for breaks, and the fit requirements can change.

On a trainer I would go for comfort above anything else. On the road I might compromise that slightly to save energy/gain speed, especially if I get to sit up on a wheel occasionally.


My outdoor bike is a 2018 Cervelo R3 which i love too much to put on the trainer. Since 2017 my Cannondale Slice Tri bike has lived on my Kickr Snap as a permanent trainer bike. I’ve not ridden it outside since IM Wales in 2017. It’s got a trainer tyre on it and a permanent sheen of sweat.

The geometry is pretty different but this doesn’t cause me any problems. The ease of always having a bike in place and just being able to jump on and start pedalling is priceless though. Remove as many barriers to the workout as you can.


Thank you for the feedback. It’s early with a small sample but the consensus seems clear. Looks like I can put this potential change to bed and stay status quo.


Best purchase I’ve made in cycling is a craigslist bike that has lived on the trainer now for 4 years. I pump up the front tire every other month to keep the bike’s spirit high. It gets 2-8 hours a week of ride time and has over 8,000 virtual miles on it all in. I wax the chain every 3 months or so; just prefer the waxed chain to keep oil/grease out of the house away from cats, dogs, lower legs, etc. I re-tape the bars every year ish. For $650 I don’t think I will ever get so much out of so little.

The majority of my racing is done on my mountain bike and the geometry of my trainer bike and my mountain bike couldn’t be any more different. My reach and hip angles are probably entirely different. The trainer bike is a large and my mountain bike is a medium. The mountain bike is SRAM Eagle XX1 and the trainer is Shimano 105. I put the seat on the trainer where it was comfortable but I have no idea if it matches my mountain bike.

All that said, when I get strong on the trainer bike I’m strong on the mountain bike. My outdoor FTP and indoor FTP’s are basically the same even on entirely different platforms (mountain vs. road). My advice would be to not worry about it one bit.

If your trainer is comfortable and easy to just jump on and ride, go with that. I don’t think your aerobic system will ever know which bike you are on.


I had an old race frame laying around. I put the same bars and saddle on as my other bikes. Geometry is pretty close between the frames though I haven’t tried to perfectly replicate it. Close enough.

Threw a derailleur and shifters on, a few parts out of the parts bin, didn’t bother with any brakes. An old tubular front wheel and it’s good to go.

You don’t need anything special. Just something to hang some parts on. You can get rolling for minimal investment.


+1 on the trainer-only bike and separate outdoor-only bike. My “nice” bike only sees a (dumb) trainer when I’m warming up for races. My trainer bike is the one I use indoors, but it also doubles for when I’m riding outside and it’s a bit sloppy out. I don’t intentionally ride in rain a lot, but there are times where I really want to ride outside and it’s a bit threatening. Or maybe it rained recently and the roads are really messy. My bike fits happen to match reasonably closely because I built the nice bike based on my build/fit of the other bike, but it shouldn’t make much of a difference unless you’re specifically training for TT or triathlon, you need to get used to riding in the aero position, and you can’t put clip-on bars on your trainer bike. Keep it as-is unless you’re just not comfortable.

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Dedicated trainer bike all the way.

Adjust the contact points to match your main ride, wrap whatever bars you have with some cushy tape and set about letting sweat destroy it slowly.


I’ve got on my turbo during the week my summer (best) bike which is a holdsworth super pro which I love to much to commute on. I then have a dedicated winter bike for commuting. Having the bike I spend the most time on and in a more aggressive position on the trainer just ready for training sessions really helped. As people have said above a more relaxed position indoors is great as you don’t have the wind, cornering etc etc, but I found for me it helped adjust into a more aero position as I could be in it a lot more over the winter and when summer comes round it’s not so much of a shock.

I was thinking this same thing and now have my old hardtail MTB set up on the trainer whilst my only road bike’s frame is being repaired. I used my road bike for the trainer and outside but constantly taking it off, putting the rear wheel on etc and cleaning it after crappy outdoor rides can be a faff. I intend to leave my old MTB on the trainer and when the road frame comes back and I build it up that will be my road/gravel bike for outside use only.

A few pals of mine have dedicated trainer bikes - some they bought new. Some were old bikes like mine and some were ebay specials. I think it makes it easier to get on the trainer if its all set up waiting. I appreciate some folks won’t be able to afford to do it too but then a trainer dedicated bike can be as cheap and nasty as it needs to be as long as you can get on with the contact points.

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Another vote for a cheap trainer bike. MTB steel frame, 10speed t/m, no brakes and a mix of handlebars, stem, saddle, etc. total cost probaly £150


Always N+1 :laughing:

I’m kicking myself for the 2003 aluminum frame and 105 9-speed that I let go last summer. Would have been perfect to leave on the trainer.

I guess I’m in the minority here but I say keep one bike.

Why? You just get used to the position and feel of the bike. Also after spending a ton of time on the trainer if you listen well to your body you can make minor micro fit adjustments that you would never figure out on the road.

I’m also a big believer of riding what you race with. No special wheels or tires or whatever because you need to understand and get used to the system or when you’re on the edge and your bike does move the way you expect it too then bad stuff happens.

Yeah people are right about the laziness. I live in a small apt so my trainer is right next where I would store my bike. I just make it a habit to put my bike on the trainer the instant I get home.

Randomness - that old bike can go to someone else who can use it and you reduce clutter.

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I agree 95%. If I were a triathlete I’d want to be able to replicate the aerobars/tuck in a pretty similar position.

If it aint broke, don’t fix it, particularly if the MTB is the outdoor racer (goal) and the more stressful position is the road bike inside on the trainer.

@vanbc - and this is “bro science” here - If it aint broke, don’t fix it. If/when you run into issues getting onto either bike, get a pro bike fit and try to match both bikes to it… Or, when your (indoor) handlebars become so corroded underneath the tape that its time to replace them, take that opportunity to get a stem/seat post etc, to match your desired fit.

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I 100% agree with this :grin:

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We all have different calculations to be made, but the only real adjustments I’ve had to make between bike fits are when only riding one bike inside for months and the first ten minutes of the first few outdoor rides feel weird… but that probably has WAY more to do with riding outside vs in a basement bolted into a stable trainer than nuanced bike fit.

If you don’t have the room for a dedicated bike, more power to you for changing wheels or setting it up every time you want to ride inside. The “special wheel” comment, is that about indoor vs outdoor or training vs racing because I’m all about saving money on tires (trainers are basically tire killers) but can get behind the familiarity argument of racing on what you’re comfortable on.

Fitted road bars on my old tri bike and use it as a trainer bike. Makes riding outside alot quicker because I don’t have to fiddle with things. Fit is about the same as my road bike, the drop is a bit more. Pink tape because it was 5 euros

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Hi @vanbc,

I also ride a Cervelo s3 on a dumb trainer. 4x week indoors and then 2-3 outdoor rides per week. I have a rubbish old 10spd wheel that I put on when on the trainer. Then swap my other wheel on when I go outdoors. Only takes 1-2mins to swap, so has never bothered me.

The only thing I have noticed is that there is a bit more wear and tear on the rear dropouts from tightening the QR 10-14/ week.

But for me I would rather wear my bike out and buy a new one every 5 years that have a really nice bike that barely gets ridden.