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power inside vs power outside
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ok. i must be doing something wrong.

i rode my trainer inside yesterday. i did 25.6 miles in 90 mins and i think my average power was like 190watts. the tire pressure is at 90psi and i don't have the trainer cranked on too tight.

if i'm outputting 190 watts outside and riding 90 minutes i'm closer to 30-32 miles.

this morning i'm riding on the trainer and in order to average 20mph i need to be outputting 220-230 watts. outside at 220-230 i'm averaging like 25mph.

can someone explain the discrepancy to me? am i doing something wrong?
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Re: power inside vs power outside [ahhchon] [ In reply to ]
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If you are training with power, don't bother with speed and distance indoors. Just focus on watts and time.

Tire pressure, tire clamping force, air temperature.. too many variables to really have that consistent watts to speed relationship.

Alex Arman

Strava
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Re: power inside vs power outside [ahhchon] [ In reply to ]
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First, i'll preface this with - you are going to get hammered for talking about trainer miles on ST. I'll try to be somewhat helpful...

Miles or MPH on a trainer is pretty much irrelevant. You can use it as a data point for consistency, but only compare indoor to indoor for miles. But in order to do this you need to crank the tire the same number of turn every time (first), then pump your tire to a consistent PSI. And even then, its just a rough estimate.

Hence, you should just focus on keeping in your power zones. The same power outside will take you further than the trainer estimates indoors.

I am consistently ~1-2 mph slower on the trainer than outside at the same power levels.


ahhchon wrote:
ok. i must be doing something wrong.

i rode my trainer inside yesterday. i did 25.6 miles in 90 mins and i think my average power was like 190watts. the tire pressure is at 90psi and i don't have the trainer cranked on too tight.

if i'm outputting 190 watts outside and riding 90 minutes i'm closer to 30-32 miles.

this morning i'm riding on the trainer and in order to average 20mph i need to be outputting 220-230 watts. outside at 220-230 i'm averaging like 25mph.

can someone explain the discrepancy to me? am i doing something wrong?
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Re: power inside vs power outside [Furious D] [ In reply to ]
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good to know. not really worried about being slammed. it's ST. haters are going to hate and i get the benefit of learning something new today.

note: i pump the tire to 90psi before every ride and i turn the crank the same every time (or as close as i can to the same).

what you're saying is that i'm not crazy. i am supposed to have worse numbers on the trainer while putting the same power output.

my focus is not the numbers. it's just something i've never understood. i try to warm up at 140-155 watts for 15 minutes. then i do a few sets of 20 mins at 200watts followed by 5 mins of 145-155watts. i do 3 sets of that and finish with a light 5 min spin cool down.

john
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Re: power inside vs power outside [doublea334] [ In reply to ]
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doublea334 wrote:
Tire pressure, tire clamping force, air temperature.. too many variables to really have that consistent watts to speed relationship.

And outside, you have drag (rider drag coefficient, rider speed, wind speed & relative direction), rolling resistance, gravity, & acceleration. More variables ^__^


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Re: power inside vs power outside [ahhchon] [ In reply to ]
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Most importantly you can't look at distance indoors. It's completely irrelevant. Depending on what trainer you are using you can put out "190" watts using a 62/11 and your distance will be much greater than what you could possibly do outdoors at 190 watts even downhill.

In any case, duration and power is what you want to look at. Speed/distance are meaningless indoors on a trainer.
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Re: power inside vs power outside [mcmetal] [ In reply to ]
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mcmetal wrote:
Most importantly you can't look at distance indoors. It's completely irrelevant. Depending on what trainer you are using you can put out "190" watts using a 62/11 and your distance will be much greater than what you could possibly do outdoors at 190 watts even downhill.

In any case, duration and power is what you want to look at. Speed/distance are meaningless indoors on a trainer.

thanks.

i'm kind of a numbers freak at times and i like to add up my time spent training and miles achieved training over the winters indoors.

i was wondering how i was able to ride how i did at some races with the limited miles put in but it makes sense now. those 3-4 hours on the trainer only got me 50-60miles but the miles were "fake" as i put in good effort and if it was outdoors i would have gotten more miles.

qt2 tells me to multiply trainer time by 1.2 if i ride the ride indoors vs outside. has anyone had any success multiplying the milage by 1.2 to see if it is close to what they get outdoors?

john
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Re: power inside vs power outside [ahhchon] [ In reply to ]
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ahhchon wrote:
mcmetal wrote:
Most importantly you can't look at distance indoors. It's completely irrelevant. Depending on what trainer you are using you can put out "190" watts using a 62/11 and your distance will be much greater than what you could possibly do outdoors at 190 watts even downhill.

In any case, duration and power is what you want to look at. Speed/distance are meaningless indoors on a trainer.


thanks.

i'm kind of a numbers freak at times and i like to add up my time spent training and miles achieved training over the winters indoors.

i was wondering how i was able to ride how i did at some races with the limited miles put in but it makes sense now. those 3-4 hours on the trainer only got me 50-60miles but the miles were "fake" as i put in good effort and if it was outdoors i would have gotten more miles.

qt2 tells me to multiply trainer time by 1.2 if i ride the ride indoors vs outside. has anyone had any success multiplying the milage by 1.2 to see if it is close to what they get outdoors?

john

I don't think you are getting it. "Mileage" on your trainer at a given power output is irrelevant to what you do outdoors. You trainer might need 200 watts to get 15mph of wheel speed, my trainer might get 22mph at the same wattage outdoors 200 watts will get you a lot more speed downhill than it will uphill. So distance covered even outdoors is of little importance.

Just concentrate on your power output for a given time and don't worry about what "distance" you've gone when on the trainer because the truth is you haven't actually gone anywhere.
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Re: power inside vs power outside [ahhchon] [ In reply to ]
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Obligatory ST response- I usually go 0 mph on a trainer cuz it is stationary.
Nice Guy reposnse- don't even try to think about or calibrate mph, you power is your power and good job for doing the same power inside.
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Re: power inside vs power outside [ahhchon] [ In reply to ]
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how are you measuring power, for real or one of those speedometers that gives you power based on wheel speed?

In either case, as others have noted the relative work is what matters--time, duration recovery all that stuff is what you manipulate indoors. You can use speed as a proxy but it's impacted by tire pressure a lot, but it might be close enough for government work absent a real power meter.

If you are concerned with miles to write in a log book just make something up
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