Before anyone else says it, I know you don't actually go anywhere when you're on a turbo trainer.
Having got that out of the way, in order to know how far in virtual distance I've ridden in a turbo session I was going to use an inexpensive Halfords cycle computer from my parts bin and attach the sensor to the rear wheel so I get a distance and speed reading.
This would work wouldn't it?
that'll be fine, yes.
I actually found cadence, heart rate and perceived effort to be far more use though.
I have a HRM that I use in conjunction with perceived effort (I keep going until I'm knackereed) but have no way on measuring cadence without buying a new bit of kit.
I'd like to know how far I've gone mainly because we're involved in a corporate 10,000 steps per day thing at work and I can legitimately convert distance cycled into steps 😉
Not sure how the effort compares with real riding. I guess you might need to hold a heart rate for a given time, then do the same on the road and compare the two distanced covered to see if you need a conversion factor. This will be useful when challenged by a colleague.
During a Sufferfest I can "cover" between 30 and 50km's. That is essentially a completely useless metric though. The turbo is all about intervals, not distance. After all cycling 10km on a turbo without intervals would take essentially no effort; there is neither air resistance or gradient to contend with. Just boredom. It's spring; just get outside and ride your bike.
Not only does it work fine, if you set the calibration correctly for one resistance (say 4), it will read power instead of mph. Much cooler in my opinion and the cheapest power meter money can buy.
Look for a power vs. speed chart for your Turbo.
My Tacx Sartori vs. PowerTap
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Ride on level 6, then 35 kmh is 300 watts (which could be displayed as 30.0 in the screen as speed), So set the wheel circumferance as 30/35 = 0.857x and there is your power.
During a Sufferfest I can "cover" between 30 and 50km's
I do a lot less - generally average about 15mph on the turbo, which I reckon is about right, as I have recovery bits where I'm barely pedalling, which I'd never do in the real world, interspersed with all out efforts, which I rarely do in the real world!
With my turbo on medium setting I average 20 mph for 15 minutes.
Don't know why I set myself 20 but I know that im absolutely ****ed afterwards so I guess that's good.
Been doing that for a week and lost 4lbs.
As mentioned above, if you know the resistance curve, then you can calculate approximate power. There are various bits of software which can help you, so if you are interested then it maybe worth getting an ANT+ sensor.
Even if the above is too much hassle, speed (and distance) are brilliant for judging your effort. I use them more than HR since HR varies so much over the effort, especially with the amount of fluid you lose and the heat you generate on a turbo.
Why not just use time? (Along with PE/HR/power..)
I only ever ride on (real) power on the turbo. But the linear relationship is very good if you don't mind not shifting resistance. Typically resistance x gearing [u]~[/u] constant anyway.
Or you can just tape some key speed-power numbers on the stem and aim for those. It is linear, after all.
I find distance travelled totaly irrelevant on my turbo, but I'm using a Kickr on specific power settings, and it adjusts to absorb the desired power regardless of cadence, so effectively it doesn't matter what gear I'm in. This is obviously a slightly more expensive option than TiRed has shown above!
However, you may find that on some turbos there is a resistance setting which isn't too dissimilar to the real world, so the same amount of effort would correlate to a similar distance being travelling indoors as well as out.
Cheers, Rich
