Virtus

I've been mulling over this question for a while and curious what others think. From a fitness perspective is there really any benefit to riding a lighter/faster bike? Given the below 4 hypothetical scenarios; if they were all completed over the same road, with the same average HR and perceived effort is there any fitness benefit of one over the other?

1. Full suspension mountain bike - 30min ride averaging 12mph (6mi ride)
2. Flat bar fitness/hybrid bike - 30min ride averaging 15mph (7.5mi)
3. Endurance/gravel bike - 30min ride averaging 17mph (8.5mi)
4. Aero road bike - 30min ride averaging 20mph (10mi)

Iride01 

Yes, all sorts of reasons might discourage you from riding if you pick the wrong bike. Might be just in your head about the aesthetics and how you feel others perceive you on that bike. Or it might be how the bikes geometry affects your fit for the type of riding you like to do or the components don't let you perform to the level that keeps you interested in riding.

Kapusta

Assuming the same exertion for the same time, it would be a wash.

What it really comes down to is having the bike that is the most subjective fun for you which in turn means you are more likely to ride more, which actually does make you more fit.

CAT7RDR

If you do not care about distance traveled and time spent, ride what you enjoy.
I have a Kestrel road bike (17 lbs) that's great for longer rides and is half the weight of my Trek rigid 29er that I prefer for local rides and is a blast even with the added weight (35 lbs).

Consistency is what matters.

shelbyfv

I doubt it matters for a 30 minute ride.

ClydeClydeson

For most people, yes, the bike matters.

Yes, a half hour of effort on bike A is approximately equal to a half hour of similar effort on bike B, regardless of the bikes. The limiting factor is how often you are motivated to get out and ride. A slow, heavy, malfunctioning, bike, or a bike that is inappropriate for the type of ride, or a bike that is uncomfortable for the rider will leave the rider less likely to be motivated to go out next time.

For instance, if you are motivated by the feeling of high speed and carving highspeed downhill corners on a mountain road, a cruiser bike with soft 2.2" tires will not be very satisfying.
If you are motivated by the challenge of extreme technical terrain and rocky trails, a skinny tired road bike will not be satisfying.
If you are motivated by challenging yourself to ride long distances on mountain roads, a fat bike with 4.8" tires with steel studs will not be satisfying.
Finally, if you are motivated by a relaxing cruise and comfy upright position, a hardcore road racing bike will not be satisfying.

And the main result of being unsatisfied is that you are less likely to go out and ride again.

Of course, everyone is different, and some people are exercise junkies who delight in putting out massive efforts simply for the endorphins or 'exercise bliss' and the type of riding is irrelevant, but if that's not you, it's best to match your bike to the type of riding that will keep you motivated, and keep the bike in good condition so your aren't losing energy to square bearings and a rusty chain.

Please note this does not mean that you need an expensive or fancy bike, just a properly maintained bike suited for the type of riding you wish to do. An old 10 speed from the 1970s with good tires and properly maintained moving parts will be 99% as satisfying as a new $3000 carbon fibre road bike, and a full rigid vintage or single speed mountain bike provides a similar technical challenge to a full suspension mountain bike, if a bit slower.

cyccommute 

It not that simple. The problem your analysis is assuming the same exertion. A mountain bike with knobby tires is harder to push along over a given distance than a road bike. Aerodynamics and rolling resistance are higher for the mountain bike than the road bike and thus mean that the mountain bike takes more energy to move over the same distance at the same speed as a road bike. You could increase the speed and effort on the road bike but then the exertion isn’t the same. And, if you increase the speed and effort on the mountain bike, it takes more energy to move it.

I don’t disagree with this.

cyccommute 

Look at your speed and distances. That tells the whole story. At the same heart rate and energy input, you are getting half the distance for the mountain bike. That means the mountain bike is less efficient. If you don’t keep the heart rate the same how much more energy would you have to use to make that mountain bike go the same distance as the road bike in the same amount of time? Or how much effort would you need to use to ride the same 6 miles on the road bike?

Ironfish653

Same HR, same power output and cadence, same amount of time?
​​​​​​ Would be the same if you did it on a Peloton
IF the goal is to become a better cyclist, or stronger in a specific cycling discipline, then pick the bike best suited to the kind of riding you're going to be doing.

If you're just going riding as a non-specific form of excercise, then pick a middle-of-the-road kind of bike ( hybrid, gravel, that sort of thing). High-performance bikes, whether on or off-road require a lot more compromises by the rider, when you're using them outside the discipline they were designed for

WhyFi

Your analysis of his analysis has a problem.

livedarklions

OP asked about equivalent time, not equivalent distance. That you'll likely go faster for the same amount of time was a given in the question, and OP even gave hypothetical (and not terribly realistic) varying mileage figures accounting for that..

Kapusta

Yes, because that is what the OP's question is assuming.

And his 4 examples show that he is taking this into account in the distances traveled in a given time.

livedarklions

You're "fighting the hypothetical" to give the answer everyone already knows and ignoring the actual question being asked.

rumrunn6

fwiw - I've read that you burn the same # of calories whether you walk or run a mile. it's just that running, takes less time

GhostRider62

200 watts for 1,800 seconds is 360 kJ, irrespective of the bike. Watts are Watts.

so, the bike don't matter none unless it is an ego thing.

63rickert

OPs query says same road and implies same conditions. In which case the difference between bike 3 and bike 4 is going to be much less than 1%, not 3mph or 15%. It might be as much as 1/2mph if bike 4 has good tires and bike 3 has junk tires. Bikes 1 & 2 will only be as slow as theorized if they are BSO junk.

Get some basic fitness first and try again.

Herzlos

Purely from a fitness perspective it really doesn't matter as long as your heartrate is the same.

However, from a fun/boredom point of view a lighter/more suitable bike will let you cover more ground in the same time frame. For example, if you've got a nice local lake that's 8 miles round. You couldn't achieve it in 30 minutes on bikes #1 or #2. Or if you've got a rough mountain bike trail, you may only be able to do it with bike #1.

The obvious answer is to buy all 4 and use the one that suits where you want to go best

cyccommute 

Virtus’ hypothesis is flawed. The problem is that this isn’t a power problem. It’s a work problem. Moving each bike requires the same power (i.e. watts) but the work done…i.e force over distance…results in less distance covered for the same force for the mountain bike. In other words, the mountain bike requires more work to move it.

seypat

I don't think I've ever seen a thread on this subject before. Well, maybe I have.

For fitness, It really doesn't matter much. Whatever bike is going to get you riding the most and give you the most enjoyment. It might come down to the color or what kind of riding terrain is available to you. In the end, it's what will keep you off the couch that's important.

cyccommute 

His distances and speed aren’t unrealistic. Assuming a “true” mountain bike and not one with slicks, 12 mph is perhaps a little high. The bike wouldn’t have to be junk. Mountain bikes with knobs are not fast and would be extremely difficult to get to speed of a fast road bike. The other bikes aren’t all that far off either.

Riveting

The most correct answer is to get all 4 (which may happen anyway), and in fact I ONLY have 4 bikes, and they happen to be the ones listed as the OP's options.

I agree that the answer to this specific question is get the one you like most, since 200 watts for 30 minutes would be the same for any bike. But this also sounds to me like the typical "I can only get one bike" question in disguise. If so, the correct answer is to get the full suspension mtb with ~2.3" tires, since it can go anywhere the others can, as well as places the others can't (IF you have access to technical singletrack, if not, get the gravel bike), and with the mtb or gravel you can also get a spare set of wheels/tires/tubes that take slick and skinny tires for faster road-only use, or longer distance stuff if and when that time comes.

70sSanO

While there are some, I imagine the number of people who do an activity they do not enjoy merely for health or fitness is relatively small, especially over a long period of time.

The ones who are successful are the ones who embrace the activity, possibly learn to love it.

Your choices are too subjective to the individual. Some people really enjoy riding a flat bar mtb, regardless of its efficiency. Probably more people enjoy more performance for their effort.

The bike for the best workout is the one that is ridden.

John

Kapusta

Same effort, same power output, same amount of time = effectively same amount of overall exercise. Distance traveled will vary depending on the bike. Given the simple and well-defined hypothetical question, the answer is really quite simple.

All the other nonsense going on in this thread is some combination of

1. lack of reading comprehension
2. obsessing over the details of a hypothetical example that is not actually germane to answering the OPs root question
3. confusion about how to apply physics terms to a real world question
4. just the desire to argue on BF.

I suspect #4 most strongly.

surak

Depends on the fitness objective. Putting aside the under-specified 30 minutes of riding hypothetical, in actuality one would have some mixture of base endurance time plus higher intensity bursts throughout a fitness/training regime. I have little experience with MTBs but what I've read confirmed that experience, which is that they kind of suck for endurance training so many MTB pros spend a lot of time training on road bikes.

Even if one is comfortable riding on an MTB for an extended period of time, a typical training route that would enable long continuous riding would usually be tarmac or gravel, and a bike in the groad side of the spectrum is simply more interesting to ride than an MTB on that terrain.

tomato coupe

Did you really not read the first post? He's asking about riding different bikes at the same effort for the same amount of time (30 minutes).