Exercise bike vs real bike

Welruc

Hi guys, im just wondering if there is any way of comparing whats done on an exercise bike to a real bike? Example: 40k on exercise bike takes 120mins at level 8, how would this time compare to a real bike over the same distance?

radia

Can't really compare easily since it would depend on the terrain, bike, weather etc. 40 km downhill is very different from 40 km uphill. Similarly, a light road bike with hard slick tyres requires less effort to move than a heavier mountain bike with shock absorbers that also absorb some of the effort and with softer, wider, knobbly tyres. And cycling into a strong wind is very different from having it behind you.

You could do reasonable comparisons if you set up a power meter on one specific bike over a particular route in calm conditions, but anything else will only be a guesstimate.

Welruc

Thanks for the reply, the reason im asking is I have been asked to cycle as part of a relay team in an upcoming triathlon in 2 months time. I have done a fair bit of cycling but its all been in the gym and i was looking for a rough way to translate this to cycling on the road. I know the terrain, wind and hills play a major part but the race is a looped course, 20k out and 20k back, so for every hill i go up i will have to come down, plus it is all raced on the road.

radia

Fair play for taking on the challenge!

Well, your training on the exercise bike in the gym will certainly help your performance in the triathlon. You can't assume that 120 mins on the exercise bike will equate to 120 mins on the race route. However, if your 40 km journey time reduces in the gym, it will also reduce on the race route. Can you cycle the race route on the bike you'll be using in advance of the race? If so, it'd give you some idea of the correspondence between the exercise bike and your bike on that route.

If not, I'd recommend you plot out the race route on something like mapmyride or bikeroutetoaster, and take a look at the elevation profile (where the hills come, the gradients etc.). Then map out something similar (hills of similar steepness etc.) near where you live, use it for getting an approx time correspondence with your gym training, and also practice on it where possible.

Also, you can use this elevation profile to guide your training on the exercise bike in the gym if you don't have ready access to a real bike. So instead of slogging along for 2 hrs at a constant level 8 on the exercise bike, put in 'uphills' (high resistance) and 'downhills' (low resistance) at appropriate points along your journey in the gym. Not only should it make it a bit more interesting, but it will also allow you to prepare better for the energy bursts you'll need and the recovery times you'll have along the real route.

Best of luck!

Khannie

It's an idea, so I'm not sure how well it'll play out, but I'd say take your bike out for a ride with a heart rate monitor on. Check your distance and time and average heart rate. Compare the heart rate for the same time / distance on an exercise bike and see how you get on.

They'll be different for sure, but the average HR difference will give you some idea of whether the bike is close to the real thing or not.