Big R

watts on a given trainer = speed...easy to figure distance from those #s...a simulated watt meter (like Kurt) is just converting speed of the flywheel into watts...and it only works if there is sufficient quality control across the product line. That being said, it's a totally different calculation for other brands ...and then again it only works if the resistance mechanism is very consistent across the line.

I agree with the others who suggest not to focus on watts indoors...focus instead on time and effort (HR).

oldspark

Never saddle a dead horse (this horse is long time dead) some one said that a mile on a trainer is not has hard as a mile on the road, too many varibles for that to be true all the time. You can ride at a very high heart rate on a trainer if you so desire so no reason for it to be easy. Time vs time is the way to go as stated above by one of the few sane people in this post (LOL).

DocRay

So one hour one the road equals one hour on a trainer, regardless of gear or intensity?

I'll stick with the insane crowd.

slowandsteady

Even if we assume that you can dial up the resistance to equal the wind resistance you would feel on the road, you still don't have to balance yourself.

curiouskid55

I agree that you can approximate energy used over a given time with energy used over a given distance. But that doesn't magically change the time into distance.

oldspark

Ah-I must draw a picture I see-do you people not train with a HRM?

MIN 

Isn't resistance on the trainer a function of speed (increasingly difficult with speed to mirror wind resistance.)

So there is another angle to consider.

merlinextraligh

I finally agree with Cypress

domestique

IMHO, I find trainer miles HARDER then road miles. You are constantly pedalling on a trainer, on the road there are a lot of downhills that I can be hitting 45 mph+ without pedalling and really tacking on miles. My trainer averages are usually a lot lower then my road averages.

And yes, you can not really simulate climbing on the trainer or a head wind (although I developed an awesome workout to simulate climbing on my trainer).... but miles are really NOT the best way to guage training anyways. TIME is a much better guage..... Power is even better.

Jack Hammer

I use rollers and I think I ride harder on than I do on the actual road. I tend to push myself much harder because I can't stay on them for extended periods, I get bored. Whereas I can go out and ride my bike for 2-3 hours and still be focused and enjoy it. Plus on longer 'real' rides I think you try to pace yourself somewhat. I think they balance out because I push much higher gears consistently on the rollers than on the road. While I'm mildly curious how if at all the two translate, I just ride the rollers to keep in shape during the winter.

Jack

ps I also put a resistance unit on the rollers, I think that's a factor too.

cacatfish

Same here. I ride the 3" dyno-lite rollers and will work harder for a given speed than I would on a flat wind-free ride. At a heart-rate where I would be about 20mph outside flat, I am about 17-18mph on rollers.

DrPete 

"Distance" as it's measured by a bike computer is the number of times the wheel, front OR rear, spins around within a certain time period. On the road, this is done against resistance. On a trainer, this is done--you guessed it--against resistance. Both require power. I have powertap files to prove that it takes the same amount of power, often times more, to spin the rear wheel of my bike against the resistance of a trainer as it does to do so on the road.

X number of watts in a certain gear for a specified length of time against a certain amount of resistance will cause the rear wheel to turn at a certain speed for that amount of time. That translates to distance.

josephvman

+1

I would think you could set any trainer up to where you're generating the same watts (and burning the same calories) as you would with one mile on the road. I know for a fact that the way I have the resistance set on my trainer that I'm burning more calories in one mile than I would be in one mile on flat ground and reasonably still air.

asmallsol

It depends on your setting. With my workout, in 30-40 minutes I get an exhausting workout. My heart rate is about 180bpm for the last 15 minutes, and I feel spent by the end of it. I feel it worked alright because I came out for my first ride and did my average 3 hour ride in the mid summer at a really fast pace.

Ritterview

Oh, the grief I got for bringing up a similar topic involving spin class. People who scoff at such quaint outdated notions as "right" and "wrong", or "good" and "evil", were wroth with righteous indignation over my apostasy of even considering tallying spin class as "miles".


https://www.bikeforums.net/showthread.php?t=256218

bassplayinbiker

Dont you guys understand that real training is measured in hours not miles.

A hour on the bike is a hour on the bike. If you've ever ridden on the road you'd know that twenty miles into a headwind is alot faster/ easier than twenty miles w/ a tailwind. So mileage isint as important than time.

texascyclist

To answer the OP's question which I think is just for the gee whiz factor, the answer is:

cadence rpm*pi*tirediameter*front ring teeth/cassette teeth

this will give you the tire surface speed of the tire in (unit you put for diameter)/minute

if you measured in inches, you will want to multiply by 60/63360 to convert to mph.

If you ride at steady pace, you can do the math from here to determine distance.

CdCf

Eh?

NomadVW 

Don't count distance at all. Count time.

Jack Hammer

Why not just count them as "trainer miles" instead of regular miles. Track them separately and make a goal based upon how you feel. As mentioned, there are so many factors in a regular bike ride that can affect an accurate calculation, wind strength and or direction, uphill, downhill, grade of hill, road conditions, etc.

Just make up your own conversion based on how you feel it is. Then set your own custom goals. eg, I'll ride 500 bike miles a month or x amount of trainer miles or a combo of the two. It's your goal, so it's not really important how it actually may convert. What's important is that you ride and enjoy it as much as possible.

Jack

jrobe

"Dont you guys understand that real training is measured in hours not miles."

A better measure (in fact the ultimate measure) is power over time with a power meter. One hour at 300 watts is alot different than one hour at 200 watts.