Bike set up power, aerobic, comfort

Increasing speed on the bike is a lot harder than it seems. To go one km per hour quicker in a 40km TT we need to find an extra 20 watts. To ride 1km/hour faster in an IM where we only ride at around 70% of our threshold power this means we need to improve threshold power by just under 30 watts.

And what would 30 watts equate to on something like a Lofty TT for an average 75kg rider- roughly 2-3minutes faster depending on your ability. And how much work is required to ride 2-3 minutes faster up a climb without losing weight- the answer is simple – A Lot!

So rather than trying to continually train more and harder to boost threshold power, it is also worth considering bike set up, to see if we can’t make better use of the power we produce.,

The basics

road-tri-GeoSure the bike, wheels and helmet can help make us slipperier through the air but the biggest gains can be made by our position on the bike. Aerodynamics is all about getting as low as we can and reducing our frontal area and reducing the turbulence we create. However setting up a bike involves far more than reducing your frontal area.

When thinking of bike set up, you have to get the balance between comfort, aerodynamics, and power output. the problem is you can’t have them all!

Bike set up aims to maximise

  • Performance power (getting the muscles in the best positions to exert the most force)
  • Efficiency (making you as aerodynamic as possible to reduce resistance)
  • Comfort (pain in the neck, shoulders, back etc. are a major obstacle for holding the TT position).

The key is to fit the bike to the person i.e. their body measurements, style of riding, event, and performance level so that we optimise all three areas.

Even though two people may be training for an Ironman they may be set up completely differently as we try to get the balance between comfort, aerodynamics and power. I always say “there is no point being super aero if you are not able to stay on your aero bars for the entire 40, 90, 180km time trial.” A correct set up will allow you to remain aero throughout.


While not as stressful as running, cycling does carry some risk. In my experience knee injuries are of more concern, as they pose a greater long- term risk. Often this is related to using too big a gear, increasing distances ridden, or set up. While not an injury as such, nerve pain in feet, hands, neck pose major challenges as they limit a riders ability maintain an optimal position.

An ideal bike set up will create a symmetrical movement pattern, that doesn’t place any excess load on the knees, back, neck. A targeted stretching/strengthening program is also helpful. A musculoskeletal screen with a physiotherapist is a great place to start. Often leg length discrepancies can lead to significant symmetry problems. Every form of asymmetry, however small, may eventually lead to issues

Bike set up

Your body contacts the bicycle in three areas; your hands, your seat, and your feet.

The relative positions of feet, seat and hands determine your comfort and efficiency on the bike. More relaxed for a road bike with the weight over the back wheel for stability, while the weight moves up and forward on a TT bike to reduce your frontal area.

There are several variables that determine these positions;

  • distance from bottom bracket to saddle
  • crank length,
  • saddle angle,
  • seat tube angle
  • saddle offset
  • distance from saddle to handlebar,
  • relative height of saddle and handlebar,
  • handlebar width,
  • Handlebar-drop on road style handlebars.

Saddle height is the one area I see a lot of problems with most beginners having their seat too high. A simple way to assess seat height is

Heel on pedal

For starters, sit on the saddle with one leg hanging free and your hips square, (not tilting to either side). Set the saddle high enough so that your other heel can just touch the pedal with your leg straight, and with the pedal at the bottom of the stroke, in line with the seat tube. For most people this results in a saddle height that leaves some bend in the knee at the bottom of the pedal stroke. This gets you close enough to your optimum saddle height that you can go through the rest of the fitting process and fine tune saddle height later.

The AIS use inside seam in cm x 88.3 to set saddle height.

It always makes me laugh when people talk about seat height thinking every millimetre is vital, and yet the position will vary depending on the thickness of your chamois or cleat, where you are sitting on the saddle which often moves depending on the effort you are producing.

However we then have to consider all of the other variables as if we change one it can affect the another area. While the basics are relatively easy, if you want to fine tune your set up then it is worthwhile working with an expert.