Tri bike vs. road bike for TR... how important is specificity?

I’m new to TR and interval training. My
Goal races are an Olympic, half, and full distance in March, May, and November.

Currently, I’ve got my road bike with clip on aero bars on the Kickr for weekday workouts and using the tri bike for the weekend outdoor ride.

How important is the specificity of using the tri bike for the TR workouts during the weekday? Is there a point in training where it’s essential to bring the tri bike into the indoor training, or are the performance benefits mostly transferable to the tri bike. I do make sure to spend about 50% of my time on the road bike in the aero bars- but that position is not as low/aero as the tri bike position.

But it’s so convenient to keep the road bike inside on the trainer…

Thanks in advance!

This is a pretty debateable topic and I don’t think you’re wrong either way. For the last 4 years I did most of my indoor training upright either on a road bike or TT. This year I’m doing everything aero. If nothing else I have become much more comfortable in aero.


Early Base and even Build phase are fine on the road bike. In some ways, maximizing your overall FTP is better via the road setup, and then you can adopt the Tri setup later.

It’s good to at least start adding the aerobar work in the Build for some workouts. But you can keep the majority of the work in the Specialty phase as needed.

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I think training specificity in this example is important. How important is probably individual. My anecdote: Build was done 100% on the road bike. Mostly TR workouts with some outside riding. Normal FTP increase of 25W. Road bike FTP compared to TT bike FTP was +25W. Started folding in workouts on the TT bike and after maybe 5-6weeks my TT bike FTP is now up +20W so just -5W off the road bike.

Can’t disagree with @mcneese.chad above but if it were me I’d complete the SST and threshold workouts in position (tri bike set up) as early as possible. So start in base especially if you are new to riding.

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If you are using the clip-on aerobars on your road bike, the difference in position between road and tri bikes is not going to be huge (certainly not as much as the difference between tri and on the hoods).

As an intermediate step, perhaps you might use the road bike, but gradually increase the % of time in the aero position.


I think think is true and different ways of training suit different people. As long as you are able to stay in the aero position for the duration of your races I don’t really think there’s a wrong answer. Plenty of riders are successful with either strategy.

How different is the geo (and the kit) on the TT bike? If you are sitting 4cm in front of the BB on the TT bike, and 4cm behind on the road bike, or if you have significantly different length cranks (eg 165 on TT, but 175 on road) then I think you would improve performance more by doing your TR workouts on the TT bike.
That’s not saying you should be doing VO2 work in the aero bars, just that significant positional changes may need slightly different pedalling mechanics, and you might as well train them. I’ve put my TT bike on the turbo for exactly that reason.
Also, you can do the rest intervals in the full aero position (and even practise your shrug/turtle) and get more used to the position for no extra time on the bike or cost to your training.

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I actually think working on your aero position in base phase is a great time to do it… get comfortable in the position you’ll race in during base when the intensity of the workouts is lower. When speciality comes round you can then get used to the race specific intensity in the aero position you’ve ingrained earlier.

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I’m trying this. It feels easier to stay in position during the recovery intervals and I’ve been working to maintain it during the higher intensity intervals. Still not sure how I’m going to stay in that position for hours on race day though :smile:


I agree with the other posters above, if the aero bar position is a good fit.

If you leave aero training until late in the plan you might not discover flaws in your position until it’s too late. I was fine on a roadie with aero bars from sprint to half, but crippled at full distance.

I now use a tri bike, been through several fittings and train mostly in aero throughout the year.


Have you ridden much outside on the TT bike?

I find indoor and outdoor riding are very different beasts and there a lots of riders who can ride in their TT position fine outdoors but struggle with the ‘locked in’ feeling of the same position indoors.

I for one find it really difficult to ride indoors in the TT position but have no problem riding outdoors for long periods. The longest I’ve ridden was a 12 hour TT that I only came out of the aerobars for eat and drink yet I struggle to stay in the aerobars indoors for even relatively short periods.

The are ways to alleviate the issues, rocker plates, or raising the front wheel higher for example but none have yet worked successfully for me. I do know my aero position works for me outdoors though and after a winter on the trainer it only takes me a couple of early seasons TT’s to find the groove again.

Whether you ride aero indoors or not is less relevant as long as you have the knowledge of how you respond to that same position outdoors, and judging the efficacy of a position you want to hold outdoors based on indoor riding can sometimes be a fools errand.


Wow lots of great info here… thanks for the responses! I am much like Julian- I put about 2,000 miles on my TT bike outdoors last year and feel pretty comfortable in the aero position at least up to the 60 mile mark which is as far as I rode it in a setting last year, but the road bike feels much more comfortable indoors, even after I built a rocker plate (which I love by the way :)).

My clip on aero bars on the road bike come
Closer to the TT bike, and the cranks are the same length, but the TT bike does have a more forward position and gets lower than the road bike aero bar position. I will try to increase time in aero on the road bike for now…

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Good point Julian! Only a few times in fact. Several velodrome sessions early on which were pretty uncomfortable trying to maintain 10 minute intervals in position but I was much, much less used to it then; towards the start of the season I was feeling more comfortable outside. My sprint and olympic triathlons last year felt pretty good but were hilly so I got a lot of “breaks” where I sat up trying to muscle pitifully uphill :smile: So I’d say yeah, outdoors doesn’t seem to be as much of a struggle now that I think about it.

I find three problems in particular training indoors:

  1. My shoulders start to ache - they are weaker than they could be due to being mobile (the left has a weak rotator cuff that I’ve been trying to keep an eye on). Perhaps strength training will help here.
  2. Eating on the bike - if I eat and then get into position my stomach feels a bit achey. This is probably something I could fix by experimenting with different food and timing
  3. The saddle and/or my shorts - the saddle is an ISM PN1.1 which doesn’t feel under or over padded, but the pad in my Rapha shorts is thick compared to a tri suit. If I rotate forward it feels like either I’m hanging off the front of the thing or I’m rubbing some tendon or other on the ‘prongs’.

I’ve got a bike fit this Friday so hopefully I can rectify some of the above issues.

Excellent advise here and my thoughts as well regarding geometry differences: muscle recruitment and breathing etc…a 73 degree STA road bike compared to a 78 STA TT bike is just a different animal. Sort of like doing all your training on flat terrain then doing a hill climb. Muscles, pedaling is ever so slightly different that it makes a difference in sustainable power output. Aerobars on a road bike don’t mimic the position of the TT bike IMO.

@Doubravsky, two points for you to just kick around in your head a little.

Point the first: I think specificity in this case can be applied narrowly to the intensity zone(s) which you are primarily targeting. For instance, if you were targeting a 25 mile time trial I would say you need to be doing threshold work, over under work, sweet spot work, etc ON YOUR TT BIKE. In other words, do race pace training in a race specific body position.

Point the second: It’s been a while since I’ve done a triathlon but for me hip angle on the bike was a very important factor in determining how well I could run. I’ve not seen your aero pos’n but am guess that on a road bike with clip ons your hip angle is going to be more shallow than most tri-bike fitters would recommend. Really, really consider whether or not you want to spend a lot of time drilling Z2 workouts with your body in that type of position. It activates more muscles in your ‘lower hamstring’ region…maybe you use your glutes a little differently…it’s just more non-specific than you might think given your chosen sport.

Not saying it’s definitely that way for you. Maybe try a couple of hardish training rides on your current trainer setup & then brick it…see how the run feels. I bet it’s different. Just something for you to kick around in your head.

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Interesting points… I’ll make sure to try some bricks with both options before making any changes.

I had this problem initially as well. After about 5 weeks of doing base in the aero position it doesn’t really bother me anymore.

I have a few pair of cheap Tri shorts that I use. I found that road shorts/bibs were too padded and not comfortable when down that far. I also rode an ISM saddle for a while. You actually should be hanging off the front. I also had some saddle sore issues with it.

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