Ahead of your big race have you invested in a triathlon bike? Are you surprised, confused or disappointed at the lack of improvement in your speeds? Or are you even slower on it than on your road bike? Here we’ll delve into the reasons this may be, and hopefully offer some solutions.
If a triathlon bike was the outright fastest and most comfortable way to get round, why wouldn’t people ride them all the time? The answer is a triathlon bike involves a lot of compromises in the way of bike design. They can be difficult to get comfortable on.
For those who need a basic explanation, a triathlon bike makes you faster by lowering and narrowing your profile against the wind. The bike frame itself is also tapered to make it cut through the air as fast as possible, but as the least aerodynamic thing on the bike is you, the focus is on getting yourself lower and narrower. Most have shifters on the end of the aero bars and electronic models also have shifters on the bullhorns to make it easier to change gear when braking, climbing or descending.
The compromise is that to improve airflow around the bike the frame, more material is needed to reduce turbulence, which results in a bulkier frame, increasing weight. On a pan flat course this doesn’t have much of an impact, but if you find yourself on an undulating course when you’re used to a featherweight road bike it can come as a surprise. Not only does a tri bike increase weight when climbing, but it makes the bike less stable on the descents due to the short wheelbase and deep section wheels, which combined with the fact that brakes on triathlon bikes are normally less efficient than on road bikes, can lead to you handing over minutes to those on the road bikes on the hills. If you can make that time back on the flats you’ll be faster overall, but if a course is relentlessly hilly, such as Ironman UK, you may be better off going for a light, responsive climbing bike.
Beyond the triathlon bike frame
There is also the question of wheels, most stock triathlon bikes will come with a very basic set of wheels to make the price point more appealing, but most triathletes will upgrade the wheels into something more aerodynamic such as a rear disk wheel or deep section rims. These are not only heavier and slower to accelerate but are a handful in crosswinds. To the extent that certain courses especially prone to strong winds ban them. If you are on a flat piece of road in good conditions they can shave valuable minutes off of your bike split, but they’re not always the right choice. If you are new to riding your triathlon bike, I recommend you use the stock wheels for a few rides, and if you plan to upgrade to deep rims for race days, make sure you get plenty of practice riding these on your long rides, and learning how they handle on the downhills/crosswinds.
A pair of expensive aerodynamic wheels will not solve all your problems though. Having dropped good money on a triathlon bike, I don’t want you to spend the same again on deep section rims and/or a disc in the belief this is the fix required. Where a pair of top end wheels will make you faster, we’re talking around five minutes over the course of an Ironman. This is massive to someone looking to qualify for Kona, but for someone just trying to get round their first event, not so much.
A much more affordable option is an aero helmet. In years gone by we would buy heavy, long and pointed helmets we would tend to overheat while wearing. These days helmets are much shorter and better ventilated. Partly due to advances in technology, but also a better understanding of aerodynamics.
In 2025, the difference between a road aero helmet and a full time trial helmet are pretty negligible, and most people would do well going for a cheaper road aero option rather than a full aero helmet. If you’re looking to win the race or qualify for the world championships then absolutely go full aero, but most people don’t need to drop that kind of money.
We’re still only talking a handful of minutes saved with an aero helmet, but again, every little helps, if you have the budget.
Getting your body ready
Along with ability to maintain speed is also the question of core strength and mobility. While properly setup aero bars can be very comfortable as your weight rests on the elbow pads, you need to make sure you have the core strength to maintain that position for the duration of your race, as you will be in a plank like position. If your core collapses in the bike leg your run will likely be a disaster as your can’t support your body in an economical position, adopting what many call the “Ironman shuffle”. The simplest way to improve this is to develop your core strength with exercises such as planks, but you can also look at adding some spacers to bring your bars higher up.
As triathlon bikes put us in such an aggressive position, we need to have the flexibility and mobility to hold that position for a prolonged period. Additionally, if we can train our body to be able to hold a lower, more aggressive position, this tends to result in faster splits.
Areas we need to address tend to be our hamstrings, hips and back. By improving hip mobility, hamstring flexibility and strength in our upper back, we can ride harder for longer in a more aggressive aero position. If you have no idea where to start with this, check out my free introduction to strength and conditioning.
Specificity in training
If you race on your triathlon bike you really need to train on it. That’s not to say that you should bin your road bike, as it is important for group riding sessions and those long off season miles, but you should stick your race bike on your turbo over winter and take it out at least once a week in the spring to get used to handling it on the road.
You should get used to riding on all conditions in all terrain on your race bike, whether it’s descending down a steep hill in the rain or threading it through a series of fast corners, you need to be confident in your handling ability to ride with confidence on race day. If you keep your race bike locked up in your shed all year and only break it out for race day you’re going to struggle to convert your training into speed on race day.
Setting up and looking after the bike
You should also put it in for a full professional service at least once a year, clunky gear changes will not only frustrate you but lose you time hand over fist. Not keeping on top of the maintenance also increased the possibility of pieces falling off! It is also important to re-index your gears when you re-build your bike when you arrive at your race. Whether your flew it halfway round the world or stuck it in the boot of your car for the local sprint race, it doesn’t take much for your gears to take a knock and play havoc with your race.
Most importantly, make sure to get a proper bike fit to get yourself into a comfortable and economical position. Your super aerodynamic position may save you 10W, but if you’re putting out 20W less than on your road bike because you’re not used to the position, you’ll probably end up going slower than on a road bike. Your position doesn’t necessarily have to be as far forward and as low as possible, it’s all about finding what works for you.
Notice the variation in width of the aero bars and the height of the stack, there’s no ideal position as it’s very individual. Of course not all of us can afford £2500 to spend in the wind tunnel finding our optimal position, but notice how they’re not as low and as narrow as possible. I personally find having my bars closer actually makes me more stable than having them wide, but it’s very individual, and comfort is king. If you’re comfortable you’ll be able to put out more power for longer, if you’re scrunched up and can’t breathe properly, you’re just handing advantage to your rivals.
Setting up your gears
Many triathlon bikes come with large chainrings and small, narrow cassettes. But what does this mean in real terms?
Triathlon bikes are designed to be ridden fast on flat roads, but strong cyclists. If you are a lighter rider, new to cycling or the course is hilly, you may want to swap the chainrings out for smaller version, and probably get a wider cassette which goes up to 30T, if not higher.
The alternative is grinding away up hills, or pedalling slower than you’d like to. There’s a possibility you could be well aware of all this as cyclist, but still want to keep the gearing that came with the bike, even though you know it’s unsuitable for you, as it makes you feel tough. Please put the ego in a box and get a setup that will actually make you faster.
Is a triathlon bike slower in some races?
Just to add to the confusion, a lot of high performance athletes will take a triathlon bike even on a very hilly course. This is because they’re exceptional athletes who live on their triathlon bikes and can throw it down a hill or round a corner at speeds that makes my eyes water, and the time they gain on the flat sections more than makes up for the time they lose on the hills.
In the Tour de France where they use both road and aero bikes in competition, some will even put clip on aero bars onto their road bike to offer the best of both worlds in mountainous time trials. This offers a sizeable advantage without the drawbacks of a full aero bike, but when using clip ons we have to reach away from the bars to the shifters to change gear, increasing our profile against the wind and slowing us down. You also have to make some changes to saddle fore/aft and your handlebars to get completely comfortable, so they can be tricky to setup. They’re a great option for hilly races or for trying an aero position without buying a whole bike, but it involves a number of compromises so should be carefully considered before taking to a big race.
Your triathlon bike may even be the wrong size for you, if you picked it up off a friend or from Ebay then there’s a reasonable chance it’s the wrong size for you. As the saddle sits further forward over the bottom bracket, the bike has a shorter wheelbase and you generally don’t reach as far forward, many people (myself included) ride a triathlon bike a size smaller than a road bike so if you simply went for the same size as your existing bike you may find you’re overreaching, and run the risk of developing lower back pain. Unfortunately even if you go to a bike shop for a sizing not many sales staff are trained to get you setup on the right bike, so if you’re spending a lot of money and really want to get it right I recommend getting a fit before you buy the bike to make sure you buy the right one.
So to conclude, if you’re disappointed with the speed of your triathlon bike, you can try the following:
-Get a bike fit
-Improve your strength, mobility and flexibility
-Spend more time training with it
-Reconsider your wheel choice
-Remember that it’s all about the engine
If you are struggling with your cycling, check out my bespoke coaching options to improve your performance for a fraction of the cost of a pair of new wheels. Where equipment can shave a minute here and there off of your time, a bespoke training plan, nutritional guidance, strength training and ongoing support can help some athletes take hours off of their PB for less than £1000.
