I have the opposite problem in terms of numbness, at least on long rides. Figured it was just that I have a better saddle on the tri bike. Otherwise I leave the road bike on the trainer and ride the tri bike on the road, as you do. Mostly just because I'm much more comfortable on the tri bike... a few years ago I raced a duathlon 9 days after crashing, and stuck with the tri bike even though my bandaged (road rash) elbow stung in aero.

Thanks for the reply.

I guess what I'm try to ask is, despite the geometry difference between a road and tri bike, will doing the majority of training on the road bike equate to better performance on the tri bike?
I thought the reason for tri/tt bike specific geometry was to recruit different muscle groups?

found an older post on this

The main reason for TT/tri bike geometry is to get you more aero by effectively rotating your whole position around the bottom bracket so that your back is horizontal (or at least more horizontal than a regular road position). It does mean that muscle recruitment is slightly different to a road bike, so you do need to spend enough time in that position to adapt. Not enough training time on a TT bike may mean that your power on a TT bike is a bit lower than on a road bike (some people find this to be the case anyway, but that the improved aero position still means they're faster overall). There's also the question of your ability to maintain an aero position on your TT bike for the duration of a race - for a HIM or IM this can take quite a bit of practice, and every time you're out of the aero position you're throwing away time.

So for those reasons a lot of people would say that ideally you'd be doing as much of your training as possible on the TT bike for that reason. Depending on the course, being able to handle your TT bike well is also a factor, since they handle quite a lot differently to a road bike, though most IM distance races are pretty non-technical. Personally I far prefer riding my road bike outside since I like doing group rides, and the roads near me are generally busy and/or pretty steep and bendy, so even on solo rides I prefer the handling and braking of a road bike. So when I'm training for triathlon (currently going through a pure cycling phase) I tend to work in what I think is the minimum amount of TT riding I need, and no more.

In short - miles on the TT bike are better than miles on the road bike. But if convenience/comfort/safety/enjoyment are putting limits on how many TT bike miles you can do, then doing the rest on a road bike is still very good training and by far the closest in specificity. Might also be worth checking your TT and road positions to get the relative distance and angles between the 3 touch points (hands, feet, butt) as close as possible. I also use a similar saddle (ISM) on both bikes. My TT position really does feel just like a rotated down version of my road position, which I'm sure helps me adapting more quickly.

I leave my road bike on the trainer and do 99% of my rides on TrainerRoad. I'm comfortable with my fit on my tri bike, and have gotten stronger/faster this year having really only ridden the tri bike in races (only done Olympic distance so far). Building into IMFL I'll take the tri bike on my longer outdoor rides, but will continue on the road bike for trainer rides.

I have been consistently using my road bike on the trainer and TT bike outside and races. I now think it's a mistake. Mainly because I have been doing FTP tests on the road bike as a result. It turns out I can't then push the same power on the tri bike. The power you can push on the road bike is generally higher and it then screws the plan of how much you can push on the tri bike. For example, I can do 236w FTP on a Road bike. This translates to 165-170w for IM distance. However, I am always frustrated that either I push 165-170w and burnout after the first lap or I end up only managing 149w (IM Austria 2017).

Next season I will do the FTP tests on the TT bike, train mostly on the TT bike unless I have a good reason otherwise. Also my TT bike saddle is more confortable, it's just a pain to put on the turbo because the back wheel comes our horizontally instead of vertically *bummer*.

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Paulo Matos

This season I have done the opposite.
I was training for the Marmotte Des Alpes Granfondo which was at the start of July and have now transitioned to more triathlon specific training for the rest of the summer targeting my 70.3 A race in late August.
In preparation for the Granfondo which was included 4 major Alpine climbs I felt I needed to get lots of road bike time in on steep climbs so all my weekend rides for the first half of the year were on the road bike doing exactly that. I left the tri bike on the trainer and did pretty much all my early season indoor training on that. The first outdoor ride I did on the tri-bike this year was two days before my first triathlon (Olympic) of the year in early June. I had absolutely no problems. The trainer time was sufficient to keep me adapted to the different saddle and position on the tri-bike and I did my best Olympic bike split to date in that race. The road bike long rides and hill work worked great for maintaining my endurance and improving power. I have no doubt there are some differences in muscle recruitment between the two positions but as long as you don't abandon one for an extended time I don't think the impact is that big.
Last year, in preparation for my first IM I rode only the tri-bike for months. When I got back on the road bike it felt horrible and my performance was awful for the first couple of rides but then quickly recovered. Generally I prefer the road bike outdoors, I suspect most people do. However I'm also very comfortable on the tri-bike and find it much better than the roadbike on the trainer.

While in theory, you want to train like you race, specificity, yada yada yada - at the end of the day, pedaling a bike is pedaling a bike.

I don't often ride the trainer, but when I do - it's a 25 year old Rockhopper with a slick.
ML is... the most interesting man in his garage.
Stay Murphy, mis amigos!

Given that in my world, the BTN (Bike To Nowhere (tm) is something to be ridden hard for a very short time (20-60 mins, max), I don't think it really matters what bike I use- hence the beater mtb.

I think there's something to be said for variety, and avoiding overuse/repetitive motion issues.
These days, I toggle back and forth between my P5, cx bike, and MTB.

IF I were racing long course (HIM or IM), I'd likely spend more/most of my time on the TT bike - but that'd be outside.
There's value and benefits to getting 'comfy' in aero so you learn to tolerate "aero neck", handling, practicing nutrition, etc.
But that's not for the trainer.

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float , hammer , and jog

This is really interesting and thank you for sharing the experience.

I've done almost ALL my training indoors this year with Trainerroad/Neo on my tri bike. I use my road bike outdoors for long rides with friends, but all my "serious" work in done indoors. I'll take out the the tri bike on a few long rides just to get used to riding outdoors before my IM in August. I have noticed I can stay in aero longer and push harder outdoors, though my neck is more sore. Thus, it's good to practice in both places before a race.

Your comment about FTP is likely spot on. Took me months to get things aligned, but I decided to use an FTP test on my Tri bike about 4 weeks ago (237w). I decided to do this test with some fatigue as well. I don't think it's possible to rest up for these tests if are training for an IM, one way or another you will be a little tired. Probably a good idea since you'll be a little tired from the swim going into the bike anyways. When I'm outdoors and during the race, I feel I should be fine riding based off the 237w number (around 180-190w NP for the race - 75% IF). If anything, I might leave a little on the table in terms of power b/c I'm pretty sure I'm stronger now, but feel like it's better to go into the 2nd half of the bike and run with a little more in the tank rather than the other way around.