# How much faster is a TT bike?



## pletharoe

We all know that a TT bike is faster on the flat than a normal road bike. But is there a rough guide as to how much faster? I'm guessing around 5km/h.


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## Addict07

Having done a lot of 2 x 20 workouts on the same road on both TT and road bikes, I agree it is in that ballpark, at least for me over that distance.


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## spade2you

Probably about that, give or take. Keep in mind that time trials are generally under 50km, so you're also pushing yourself much harder than you might on something significantly longer, although we typically rely on drafting on the long races.


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## Dan333sp

Slightly off topic, but during the coverage of the men's and women's TT, I noticed that the team cars following the riders mostly seemed to have one backup TT bike, and then one backup road bike on the roof. Anyone know the reason? Is it just a matter of cost and not being able to have more than 2 TT bikes set up for one rider at a time?


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## spade2you

Mechanicals happen. Sometimes it's faster to change bikes than to swap wheels, provided it's a wheel problem in the first place. There's a lot at stake, so these guys tend to have a 2nd bike ready to go if they're a TT or GC rider and in contention for the win. 

As for the difference in speed, I'm about to take my road bike on the TT route because I haven't ridden that route without maximum aero in several years. Should be interesting, at least to me.


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## Dan333sp

spade2you said:


> Mechanicals happen. Sometimes it's faster to change bikes than to swap wheels, provided it's a wheel problem in the first place. There's a lot at stake, so these guys tend to have a 2nd bike ready to go if they're a TT or GC rider and in contention for the win.


I know that, I was just confused as to why they'd have a spare TT bike and also a spare traditional road bike on the roof of the team car, while riding in the TT. You can just make out what I'm referring to in the back of this picture, the bike on the right is a TT rig and the left is a road rig-


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## xjbaylor

Dan333sp said:


> I know that, I was just confused as to why they'd have a spare TT bike and also a spare traditional road bike on the roof of the team car, while riding in the TT. You can just make out what I'm referring to in the back of this picture, the bike on the right is a TT rig and the left is a road rig-


I imagine that no team has 3 $10k+ TT bikes per rider. So, since they have the rack space, they go ahead and carry a third bike, by default, the riders traditional road bike.


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## waldo425

Dan333sp said:


> Slightly off topic, but during the coverage of the men's and women's TT, I noticed that the team cars following the riders mostly seemed to have one backup TT bike, and then one backup road bike on the roof. Anyone know the reason? Is it just a matter of cost and not being able to have more than 2 TT bikes set up for one rider at a time?


If you go through two bikes you're pretty well screwed. They have the road bike there so that you can at least ride a bike to the finish.


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## Wookiebiker

In general you will see a 1.5 mph - 2 mph boost in speed between a TT and a road bike...assuming the rider is using regular shorts, jersey and helmet along with no aero wheels. Most of that is due to the differing rider position (i.e. more aero).

To go beyond that you need the skinsuit, wheels, shoe covers, helmet, etc. Which will give you another 1 mph - 1.5 mph gain in speed.

So...anywhere from around 1.5 mph to 3.5 mph gain in speed over a road bike on flat roads.


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## spade2you

I'd probably say I'm 3mph faster. 4mph slower on the road bike today when I turned around into a hair dryer headwind on my way home. I've been riding way too much indoors this year.


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