Last Sunday, I was out on my winter training hack. I averaged 16.8 mph for 70 miles and that was by sitting on Baines’ wheel for most of the ride Yesterday I went out on time trial bike (with non-aero helmet and wheels) and averaged 21mph for 50 miles over similar terrain. In an incredibly unscientific method of deduction, that’s about 4mph faster on time trial bike. It’s probably not quite that much. My legs felt better yesterday, and there was a little less climbing. But, as a rule of thumb, if you go from a road bike to good time trial set up, you should be able to go 1-3 mph for the same power effort.
It depends on many variables. My summer road bike stripped down is a good 1-2 mph faster than a winter training bike with mudguards, creaking gears and heavy road tyres. Maybe there is a psychological benefit that when you get on a time trial bike, which makes you want to pedal faster.
How much faster is a TT bike?
One of the great debates in cycling is how much faster would an old school time-triallist like Alf Engers have gone on a full time trial bike with dischwheel e.t.c? It’s impossible to say. Some of the 1970s time triallists had their position down to a fine art. It was only really the arm positions which could have been improved on with tribars. Though discwheels and skinsuits would add quite a bit too. In 1978 Alf Engers did a 49.24 for a 25 mile time trial ( 30.3mph / 48.8g km/h). That was before TT bikes, aerobars, discwheels and aero-helmets – to say nothing of wind tunnels and modern nutrition methods.
The current 25 mile time trial record is 45-46, set by Michael Hutchinson in 2012. (32.5mph / 52.7 km/h) – nearly 4km/h faster
UCI athlete hour record and UCI Ultimate record
One interesting comparison is Chris Boardman’s hour records. Boardman set hour records of 52.270km and later 56.375 km. This 56.3km stands as the ultimate hour record – using an extreme ‘superman’ position – Boardman was literally flying through the air.
Then the UCI changed the rules so basically you had to use 1970s equipment. In 2000, Boardman just beat Merckx to set a new athlete’s hour record of 49.441 km
That suggests a 7km/h difference between the fastest time-trial position and an ordinary road bike.
In practise, the superman position has been banned from most competitions. The average time trial position is somewhere between the Superman and road bike.
Disadvantages of time trial bike v road bike
- Heavier. A time trial bike is typically 1-2kg heavier than a road bike. This is because the main focus is making a time trial bike more aerodynamic rather than lightweight. TT frames tend to be heavier because of bigger ‘aerofoils’ and bigger frames. This can put a time trial bike at a disadvantage going up hill. Tribars are also heavier than a simpler road bike handlebar.
- Handling. If a time trial bike is faster why don’t people use it in road stages? The UCI have disallowed it because simply they are more difficult to handle (plus the UCI dislike the aesthetics of TT bikes). TT bikes are a bit heavier in their handling. This is due to the geometry of the frame, but also because the handlebars are different. It is harder to make fine adjustments on narrow tribars. This is not a problem when doing a solo time trial, but it would be a big problem in a busy peleton with people fighting for position.
- Different position uses different muscles. The set up on a time trial bike, puts you in a different position. Becoming more aerodynamic can lead to a loss of power. This is especially a problem if you don’t train in the time trial position and get used to the position. It means road riders who do a time trial in a grand stage, may struggle if they haven’t practised for many hours on a time trial bike.
- Discomfort. A time trial bike lends itself to a more aerodynamic / uncomfortable position. You place a lot of pressure on your bike, shoulders, neck, groin. If you’re not used to it, it can be torture; even if you are used to it, it still ends up being painful. When Fabian Cancellara was asked what is most difficult training session was – he immediately replied a six hour ride on the TT bike. This is a good reason why ‘touring cyclists’ would not choose aerodynamics. It’s more important to be free of pain and enjoy the ride.
- Anti-social I guess one of the main drawbacks of TT bikes is that they are antisocial. Don’t turn up on a group ride on a TT bike.
Is a road bike ever quicker for a hilly time trial?
- Many people assume that for a very hilly time trial, you might be better off on a road bike because the weight saving and better handling outweigh the aerodynamics. As a general rule, the aero benefits of a time trial bike will always trump the weight saving and handling on any hill time trial. Road bikes are just slower, even on very hilly course. It would have to be a ridiculously hilly time trial for a road bike to be better. Perhaps really severe climbs and descents so you are hardly pedalling on the descent. Perhaps the Bristol CC hilly time trial around Dursley with a course record of around 20mph might fit the bill. But, if if in doubt use the time trial bike if you want to go faster.
- Hill climbs. It seems counter-intuitive. But, there are even hill climbs where a time trial bike is quicker than a road bike. If the gradient is 4% or less, the aero benefits can outweigh the weight saving. If there is a headwind up the climb, the benefit of an aero bike is even more pronounced.
So why don’t more people ride TT bikes?
When I get on a time trial bike, I get a real buzz from the speed. That’s one of the attractions of cycling – self-propelled speed. It is uncomfortable, but the more you ride it, the more used to the position you get. But, unless you are doing time trials, most people are reluctant to spend money on a bike they won’t use very regularly. I like both the road bike and the time trial bike. For a ride around the hills of Yorkshire and the Lake District I would choose a road bike. But, I also like the time trial bike sessions in a different way.