Is a tri bike really faster than a road bike? And if so by how much? Is it just seconds or does it save you minutes? If you’re thinking of upgrading your bike for triathlon and don’t know which type would be best for you click on through for all the answers.
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There is a couple of parts to this question, firstly is a tri bike really faster than a road bike?
The answer is almost universally yes. Although there are a couple of points to note first. The bike must be the correct size and must be fitted correctly for it to be faster. There are also a couple of races where a road bike might be faster but not many.
Races such as Embrunman the long distance triathlon in the French alps might be one example. But it tends to only be the most extreme races with a lot of long sustained climbs and descents that are better suited to riding a road bike.
So if a triathlon bike is faster how much faster is it?
I can only go on my personal experience here and explain how I came up with the numbers I’m quoting. There’s a training session we do which includes long intervals done at Ironman race pace. We do it on a short lapped circuit which eliminates a lot of variables like changes in weather or terrain. Because it is very measurable and consistent it’s easy to compare bikes on it. It also tends to be a long ride of four to five hours. This eliminates inconsistencies in effort level. If I start too fast I’ll blow up and this will show up in the lap times.
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So if I ride the same session on the same lap in similar weather on back to back weekends whatever speed differences you are left with from one week to the next should to be as a result of the bike. These are obviously not laboratory or wind tunnel conditions but I’m not trying to measure tiny differences.
The differences between these bikes is measured in minutes not seconds.
I rode this session on three bikes over three weekends and found a marked difference between all three. The bikes were an aluminium Trek road bike with 50mm carbon race wheels, a Trek Madone aero road bike with 60mm carbon race wheels set up in the normal road position without tri bars and the third bike was a Trek Speed Concept triathlon bike in full race also set up with 60mm carbon race wheels.
The results between the regular road bike and Trek Speed Concept were almost exactly as I expected but the Trek Madone surprised me. It was much faster than I had expected it to be.
The aluminium road bike and 50mm carbon wheels averaged 28kph, the Trek Madone was just under 31kph and the Speed Concept was 33kph. All three sessions were five hours long and included three times one hour at Ironman race pace efforts.
The weather was similar during the three sessions and there was only fifteen days between the first and last ride so there wasn’t going to be any great difference due to an improvement in fitness over such a short period.
Average speed and distance covered
- Aluminium Trek road bike with 50mm carbon wheels: 28kph – 140km
- Trek Madone road bike, road position. No tri bars and 60mm race wheels: 30.8kph – 154km
- Trek Speed Concept full race set up, 60mm race wheels: 33.1kph – 165.5km
This is a fairly massive difference in speed. Over the 180km of an Ironman bike split the Speed Concept in full race set up is over an hour faster than the road bike with race wheels. Over an Olympic distance race of 40 kilometers the difference would be about 12-13 minutes from the slowest to the fastest set up.
Time to ride 180 kilometers at these average speeds
- Aluminium Trek road bike with 50mm carbon wheels: 28kph = 6h25
- Trek Madone road bike, road position. No tri bars and 60mm race wheels: 30.8kph = 5h51
- Trek Speed Concept full race set up, 60mm race wheels: 33.1kph = 5h17
This is over an hour off your Ironman bike split. For most people this is a typical improvement that you would see after a year or even two years of consistent hard training.
Why is a tri bike so much faster than a road bike?
So what is the difference? Maybe it’s a bit more obvious why a regular aluminum bike is slower but how is the Speed Concept so much faster than a top of the range aero road bike like the Trek Madone? You can see in the two images below that they both have a similar skinny, wind cheating looking front profile.
The biggest part of it really comes down to position. You and I are the least aerodynamic part of the package and changing our position into one that’s much more aerodynamic is where the biggest speed difference comes from.
You can see in the image below that the rider on the left presents a much taller profile to the wind (A) compared to the rider on the right’s profile (B) and as such is creating a lot more drag (you will have to excuse my non-existent photoshopping skills)
This is where the single biggest difference in speed comes from with a tri bike. The position we can ride in while remaining both comfortable and powerful. A correct bike fit and a tri bike allows you get into a much faster position than a road bike due to it’s geometry.
The main difference is that the seat angle (the yellow line below) is at a much steeper angle (Z) than on a road bike.
This allows you reach further forward and at the same time get a lower position without closing down your hip angle. Closing the hip angle might help improve aerodynamics as you get lower at the front but at the same time it would compromise your power output.
So it’s a combination of both the bike being faster and the rider also being in a more aerodynamic position that gives the big increase in speed. Bot of these can be looked as being aerodynamic gains. Essentially “free” speed in training terms, not in financial ones unfortunately.
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