Tri/TT-bike vs Road bike – what should you choose?

This is the English version of my blogpost in Norwegian released a couple of weeks ago.

Doing a triathlon does not necessary require much equipment (seriously, it don’t!) A swimming trunks, swimming goggles, bike, helmet and a pair of sneakers is what you must have. Most off you naturally end up having a lot more than that, and the issue of bike comes fast on the path of someone who is bitten by the triathlon bug. The list of equipment I use is under  «equipment» .

Tri/TT-bicycle or a road bicycle?

Let me give a brief overview of what I believe are the advantage and disadvantages of the two different types.

Road bike


  • Better comfort, especially if you are an beginner and if you have not gotten a good bikefit on tricycle (for me who rides on my tri-bike 500 h/year and has got a very good bikefit, I find the tribike to be more comfortable)
  • More versatile – can be used in both triathlon and road race
  • Lighter – in equal price range is typically a few kg difference in favor of the race.
  • Better in climbing and technical cycling downhill – personally as I found the differences are small, but the general opinion is that a road bike is better up- and downhill.
  • Cheaper – In addition, they are usually easier to get sold and have a larger and more actively used market, though  triathlon stock market  starts to become pretty good.
  • Easier to maintain / repair – especially if brakes and cables going out.


  • worse aerodynamics



  • better aerodynamics


  • Less comfortable – especially if that made a good bikefit, as there are fewer people who are good at
  • Less versatile – whether you like to be involved in a lot of different
  • heavier
  • Poorer in climbing and technical cycling downhill
  • More expensive to buy – although there are many bargains to get used
  • More difficult to maintain/mount/adjust

By setting it up in this way the choice looks clearly like a no-brainer. In truth it is a no-brainer too. If you are going to participate in a triathlon then a tri bike is completely superior from a performance perspective (!).

Aerodynamics is so incredibly important that dispite the disadvantages, it is so much much better regarding performance. If you are a cyclist who wants to try a triathlon competition or do not care at all about the time used, then a road bike is a good choice. If you are hooked on triathlon and time is important to you, then a tri bike is the way to go.

So how big is the difference?

In 2013, I tested this in a wind tunnel in Southampton followed by real world testing where I rode a relatively flat 5 km section back and forth (total 10 km) with identical watts, measured by the same powertap wheel. One setup was my earlier Specialized Shiv with Zipp 808 with front wheel and aero helmet. The second was a regular road bike with low profil front wheel and a normal road helmed. In both of the setups I road as aerodynamically as I could getting my body and head low. The theoretical numbers in the wind tunnel was quite similar with the practical trials and the answer was that the tri bike was 6 seconds faster per kilometer compared to a road bike. If this does not sound like much, it will mean 1 minute per/10km and 18 min over 180 km(!)

Racer bike I tested in the wind tunnel in 2013
SHIV was tri bike I tested
In the practical test was the Shiv and a Jamis road bike tested

What about the hills?

When riding flat about 80% of the energy is used to overcome air resitance (bigger percentage at higher speed than the lower), while when riding moderate uphill 80 % of the energy is used to move you vertically upwards. Therefore aerodynamics has a much lower impact while riding in hills. That is also the reason why I sit upright when riding in hills (except if they are relativly flat or there is a solid head wind), because I belive the gain in changed muscular strain is greater than the loss of more aerodynamic resitance. Most competitions are have major advantage of improved aerodynamics rather than lower weight. Norseman has a lot of hills, but the most of the course is either flat or have untechincal downhills where good aerodynamic is very important. Thats why I belive a tri bike is  superior in races Norseman and Swissman, despite all the climbing. Aurlandfjell Xtreme Triathlon is the only competition I know where I would recommend a racer rather than a tri bike.

Aerodynamic is very important for fast riders, but not so important for the ones riding at slower pace, correct?

That is a hard-dying myth. Many people know that air resistance increases four times with double speed. Air resistance at 40 km/h is four times as high as that at 20 km/h, and it requires 8 times as high wattage, to maintain the speed. A fast cyclist will therefore use a larger proportion of watt to overcome the aerodynamic resistance than someone who bikes slower and have a higher profit if we measuring the profit in percentage of time. Since that bikes slowly takes longer for a given distance so, however, the slower rider gets a higher profit if we measure the profit in time. If we take an improvement in aerodynamics from 0.30 to 0.25 CdA (CdA= a term for aerodynamic resistance), the time saved by the different average speeds over 180 km as follows:

  • 40 km / h – Time savings:  15 minutes and 3 seconds
  • 30 km / h – Time savings:  19 min and 12 sec
  • 20 km / h – Time savings:  25 min and 43 sec

More information on the topic and detailed calculations, you can read the post:  Fast VS Slow cyclist – the importance of aerodynamics


In summary, there is no doubt. Performance-wise, a tribike is superior to a road bike, and the discussion of tri vs racer is pretty pointless (unless you will be involved in Axtri).

In recent years there have been lanched aerodynamic road bikes on the market. Combined with electronic gearing and a more aggressive geometry it is possible to build the up the road bike relatively similar as a pure tribike. The question tri bike vs aerodynamic road bike with clip-on aero bars, however, it is a very interesting question. In collaboration with  Boardman bikes  and  Anton Sport Sykkeldelisk,  I will test it out in the spring.

We will build up a Boardman AIR road bike w clip-on with identical measures as my current Boardman TTE tri bike. What are the advantages / disadvantages of the two and how much difference is there? It will be interesting to find out!

Do you have any questions in this context? Something you would like us to test? Write it in the comments and we’ll see the option to get it tested.

Boardman TTE Signature – Bike of referance: D
Can a road bike come close to this setup?
This is the bike that’ll try. With identical bike position and clip-on aero bars so the differences may not be so big?
Med Ultegra Di2 giring and Boardman Air Elite carbon wheel set.
This special version of Boardman AIR (front brakes are not hidden) was first and second at the Olympics in Rio 2016 with Alistair and Johnny Brownlee. The bike clearly has a large potential.
Older brother Alistair in front with Jonny directly behind him the Olympic Games in Rio 2016. Both on Boardman AIR.

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Jeg er en 31 år gammel triatlonentusiast som prøver å bli så rask som mulig til å svømme, sykle og løpe. Treningen, konkurransene og utstyrsmanien blir godt dokumentert på bloggen min.

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