6

Due to my current life situation, I can no longer have both road and mountain bikes for their respective types of riding. I'm currently doing everything on my mountain bike. For long-distance on-road training rides, how would riding on a road bike compare to riding on an MTB? Eg. what would be the equivalent MTB distance (on-road) of a 100km road ride or something? For context, I used to have a mid-tier modern road bike, and my mountain bike is currently a 140mm travel 29" full suspension rig.

9
  • 3
    So hard to compare. 20 km in the Sea-to-Sky is absolutely more difficult than 40 km in Bend, OR. So how do you compare either of those to road riding? Best I can say: comparable times in different heart rate zones.
    – Paul H
    Nov 8, 2022 at 7:08
  • 1
    What tyres are you using? The answer is going to be quite different for an XC tyre and an Enduro tyre
    – Andy P
    Nov 8, 2022 at 9:08
  • 1
    To me, having both types of bikes, the elevation difference of the chosen routemakes a bigger difference between rides on the tarmac, than choosing the bike type does. With faster XC tyres the MTB bike is slower, but not drastically. It is an older mountain bike with the narrower handlebar type with bar ends, though. Nov 8, 2022 at 10:32
  • 3
    For what it's worth, when I was actively road racing all my training was based on time and effort. Distance was irrelevant. Rides were planned and discussed in terms of time, not distance. Nov 8, 2022 at 10:43
  • 1
    @Hursey Oh, I go on plenty of trail-only rides too. I'm only asking about how to handle the road riding side of things. The relevant part of my question is horribly worded--thanks for alerting me to fix it.
    – MaplePanda
    Nov 9, 2022 at 3:48

5 Answers 5

9

To compare anything, try and convert it to the same unit of measurement.

Time is convenient, but doesn't denote the effort. So consider your input effort - a 2 hour ride in zone 3 (tempo) has the same physical drain on you no matter if its road or MTB.

enter image description here

or similar info another way - note there are differences between two charts.

enter image description here

  • zone1 is "I forgot I was riding a bike while talking"
  • zone2 is "can carry on a conversation with full sentences like you're standing still"
  • zone3 is "can carry on a conversation with full sentences, but breathing hard while the other person talks"
  • zone4 is "can gasp out 2~3 word chunks"
  • zone5 is being able to say single words "yeah / nah / k" only if you have to.
  • zone7 is an odd presentation - it would be the level of effort you put in to avoid an accident, or a max-effort takeoff from a traffic light. The duration is too short to be reflected in heart rate peaks.

Differences arise in the "continuousness" of the effort. Road tends to have sustained zone 2/3/4 for multiple minutes whereas MTB is generally more bursty depending on terrain.

MTB is likely to have peak-efforts for short duration (which stresses your fast-twitch muscle fibres) whereas longer steady efforts push the slow-twitch "endurance" muscle fibres.


Ultimately, compare how you feel after a ride - if you're shattered, that's a hard ride no matter if it was road/mtb/trainer/etc.

5
  • Where did this table come from? Id like to see the article or webpage that was associated with it! :)
    – Flats
    Nov 8, 2022 at 20:23
  • @Flats yeah it was an image search for "cycling zones" I should find something better that shows things like "approx percentage of max heart rate" for each zone.
    – Criggie
    Nov 8, 2022 at 21:03
  • 2
    @Flats found it - the original image was credited as "table courtesy of Dr Andy Coggan "Training and racing using a power meter: an introduction"
    – Criggie
    Nov 9, 2022 at 9:11
  • @Flats This image is chopped down from a well known table. The full version is uploaded in another answer with the image link found here: i.stack.imgur.com/LqTZA.png
    – Andy P
    Nov 9, 2022 at 9:57
  • 1
    @Criggie if you want a replacement image here is an excellent one i've used in an answer in the past: i.stack.imgur.com/yeiul.png
    – Andy P
    Nov 9, 2022 at 9:59
7

Very hard to give a simple answer that will be precise enough to be useful. MTB geometries vary enormously from upright and not aerodynamic to less up right a slightly less not aerodynamic, so speed you ride makes a big difference. They are heavier -so impact if you ride hill circuits will be more significant than flat ground. The biggest issue is tires - the rolling resistance of MTB tires varies considerably. The biggest factor to consider is the riding positions are so different they work muscles differently. The training you do on a MTB is best though of a more like cross training instead of quality road cycle time.

So given the answer is so variable, the best thing is measure. If you have metrics from your road bike days, use these as a baseline - ride the same time and the same output (power would be ideal if you have it, otherwise Heart rate will suffice) on the MTB and see how far/fast you go. This is at best and approximation, but it is the easiest. If you do not have metrics from you road days, you probably have a good idea of distance/time/speed and how you would feel though a road ride. Try to emulate the feeling over the same time and ignore speed and distance (maybe even remove the speed sensor from the MTB, you will look at the speed and push harder thinking 'This is a ridiculous effort for how fast I am going)

5

I'd say the scientific way to approach this would be to put a weight, rolling resistance and air drag parameters on the bike and then consider the average speed at a certain amount of watts flatland, another amount of watts uphill and a third amount of watts (probably zero) downhill.

An example: 70kg rider, 12kg road bike, 10.3 watt @ (29 km/h, 42.5 kg) rolling resistance (Conti GP 5000 according to bicyclerollingresistance.com), 0.4 square meters Cd*A, 110 watts flatland, 220 watts uphill, 0 watts downhill, 17% uphill 6% grade, 17% downhill 6% grade, rest flatland.

For these parameters, I get 24.0 km/h average speed.

For MTB, the bike probably has a weight of 19kg, the tires 22.4 watts in same conditions (Schwalbe Nobby Nic according to bicyclerollingresistance.com), Cd*A 0.57 square meters.

For these parameters, I get 20.4 km/h.

So, one kilometer on MTB corresponds to 1.18 kilometers on road bike, given this rather low power level.

If we multiply power level by 1.5, I get 24.8 km/h for MTB, 29.0 km/h for road bike, so it's 1 km on MTB = 1.17 km on road bike.

So there's a difference but it's not as large as you'd expect. Of course, a suspension fork (or worse, suspension frame) you can't lock when climbing uphills standing could rob more power, putting the favor more towards a road bike.

The uphill and flatland speeds were equilibrium speeds, the downhill speeds included dynamical effects (considering the slow acceleration from flatland speed to equilibrium speed, assuming a 200 meter long / 12 meter high hill), and then the speed figure is the average speed calculated in the correct way.

Now this is only for energy used. Of course, riding on a road bike with very low handlebars could develop your arm muscles more than riding MTB does, so if you consider this the balance could tip the other way.

4
  • Funny you should mention Nobby Nics - I run one on the front when I'm riding trails, but for my WTB nanos for long distance mixed surface on my hardtail.
    – Chris H
    Nov 8, 2022 at 22:09
  • Well thought out answer that matches very well with my real life experience.
    – Andy P
    Nov 9, 2022 at 0:03
  • The bicyclr rolling resistance bumbers are for ideal steel drum, not for real road surface. Nov 9, 2022 at 6:44
  • Pretty close agreement to my numbers (1:1.25) from a very different approach as well, given that I had rougher terrain, which would also have led to unlocking the suspension.
    – Chris H
    Nov 9, 2022 at 11:20
3

I've been known to use my hardtail for the sort of distances I normally do on my tourer. You sound like you're using your mtb on road as well as off. So here are some subjective numbers.

The bikes weigh about the same in my case - nearly 20kg plus tools and supplies - if anything the tourer is a little heavier which is an unusual position to be in.

Obviously the tourer is more aerodynamic, and has lower rolling resistance tyres, though the WTB Nanos I use for long rides on the hardtail aren't bad.

It's still hard to make a direct comparison because the long rides I do on the hardtail have more off-road than the ones I do on the tourer. But an example from earlier this year (200km of which about 40-50km was easy gravel, 10-20km rougher but non-technical bridleway, and the rest road) took the sort of time I'd expect for 250km of road (and a little gravel) on the tourer, with similar hills. The tiredness matched the timing. So that suggests very roughly 25% harder on my hardtail than my tourer over the same distance, with only slightly rougher terrain. A previous ride of 160km on the hardtail used harder terrain, including crossing a ploughed field muddy enough to jam the back wheel, so was harder still; sticking to the same road/easy dirt tracks that I might do on the tourer would be a little easier.

You'll pay a penalty for the extra rear suspension and the extra weight of your mtb compared to your road bike, but you'll gain on the terrain compared to me, so treating mtb rides as 25% longer road rides is probably still a reasonable guess. If you'd be very quick on a road bike you're losing more to aerodynamics than me.

This assumes fairly easy-rolling tyres by mtb standards, pumped up harder than you'd use on trails. That would be a worthwhile investment if this is going to be a habit. If you want a 1-bike strategy, you might want to look at switching to a hardtail with lockout on the forks, and perhaps fitting clip-on aero bars (which I have and wanted to try on that 200 but was defeated by rusty bolts)

0

I too only mountain bike these days and now only on flat roads because I moved from California to the East Coast. But I am surprised by the answers I would have said a road bike could go at least 5X farther than a mountain bike on the road. Easy. I used to do centuries on my road bike but now I do not like doing much more than 15 on my mountain bike although I don't press it. I ride every day instead of taking long trips. But my road biking was 40 years and 50 lbs ago. Is my weight really making that much difference?

2
  • 1
    Welcome to Bicycles SE. Your answer finishes with a question. Maybe you could submit it as a dedicated question?
    – Ted Hohl
    Mar 29 at 3:45
  • Strange to me that you would ask about weight and not the 40 years that as elapsed between now and when you used to ride centuries.
    – Paul H
    Mar 29 at 18:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.