Partially inspired by this thread about running. When I ride my mountain bike, regardless of terrain, I feel the need to change to a higher gear when my cadence gets up around 85 and I’m quite happy with it sitting at around 75-80 rpm. By comparison, on my road bike my cadence sits comfortably around 90 and I can have it up between 100 and 110 for long periods of time without feeling the need to change. If it gets down to 80-85 I’d be looking to change to a higher gear.
Why would there be a difference?
The cadence sensor and bike computer are the same for both bikes. The only differences I can think of that may have an affect are the basic position, on the mountain bike I’m much more upright, while on the road bike my back is lower and flatter. Also there may be a difference in crank length (I haven’t measured) which could change how easy it is to turn my legs at a particular RPM.
There are probably differences in seat position between the two bikes. Even if you do your best to make them as close as possible the height and fore-aft position are going to be slightly different. This can make one bike easier to spin on. Not that 75-80 is exactly grinding.
Personal preference? Back when I rode a lot, I tended to keep a pretty high cadence (100-110), regardless of whether I was on my road bike or my mountain bike.
It’s pretty common to have 170 cranks on road bike and 175s on a mt bike, but that should’t make too much difference. Make sure your saddle height is set properly, but other than that it’s probably just a difference in posture. Cadence is a function of the gear you choose, so things like rolling resistance shouldn’t make any difference.
If anything, with the tendency for MTBs to have lower gearing you would think that you’d have a higher cadence on that. Do you ride with people more on the road bike? Maybe having the peloton to keep up with inspires you to ride a little harder?
I assume that you’re more upright on the MTB (and maybe have a wider saddle), and that’s probably enough to make higher cadences less comfortable. Being upright is a little less stable for balance, and keeps more weight on the saddle, both of which could be factors, as well as just the positions of muscles and joints in the two different postures.
I go with the first answer. I had a mountain bike and a road bike, and I ended up giving up the mountain bike because it was SOOO much harder to pedal and slower. I could do a hundred miles on my road bike, but maybe 30 on my mountain bike.
I typically ride alone. This all based on my subjective feeling of how fast I’m spinning compared to what the cadence actually is. On the MTB at 80 rpm I feel like it’s 90. Take it up to 85 and I feel I need to change to a higher gear to maintain ~80 rpm. On the roadie this feeling of high cadence happens about 10 rpm faster.
I think it probably is crank length and spread of the pedals. Another possibility is that it’s related to my slower speed which would normally be associated with climbing a hill on the road bike and I tend to lower my cadence to around 80 when climbing. I’ve been riding road bikes for years but only recently got into the MTB.
This lower cadence on the MTB happens regardless of the road surface, it doesn’t seem to be due to riding trails or anything like that.
Rolling resistance has nothing to do with the cadence you choose or how far you can go? So you use the same cadence going up hill and going down hill? I’m not sure that’s common.
It has an affect on how far you go, but it shouldn’t affect your cadence. The cadence is selectable by choosing an appropriate gear. It is only once you run out of gears in either direction that your cadence is necessarily affected. So yes, generally you would have the same cadence going uphill as downhill provided the bike speed is within the range catered for by the gears.
I’ve checked my cranks, the MTB ones are 175 mm and the road bike has 172.5 mm. A small difference but maybe significant? One day I will put shorter cranks on the road bike and see how that affects my perceived cadence.
Of the ones given so far position seems the most likely to me but honestly I’d guess more of it is a more subconscious preconception … you “know” the MB is heavier and think of it as a more testosterone-laden beast that you are “expecting” to be mashing on climbing, out of seat over rough terrain, and such … spinning it just doesn’t fit with that preconception. On your mountain bike you are imaging powerful. Road bike psychological preconception is an endurance event . Probably the way they are geared differently plays into those mindsets as well.
I have a touring bike that’s geared like my mountain bike (for climbing hills under a heavy load). It’s all steel, and I’ve not weighed it but it’s heavy even without a load. My road bike is a low-end carbon bike marketed as an endurance model, and comes in at 9.15 kg (no water bottles, but I left the parts/tools bag on the seat post), and of course it’s geared like a road bike.
Psychologically they’re both meant for endurance activities, but to go the same speed on each of them I feel like I’m spinning the road bike and mashing the touring bike (I do have cadence data for the road bike, but only subjective experience for the touring bike). Of course I can obtain a higher top speed on the light bike, and be much less tired to boot.
Similarly, my mountain bike is a hard tail, but when using a mate’s FS I was always frustrated on the way back and forth to the trail. Damn, that bike was hard to keep moving!
Perhaps ironically, I completed my only Imperial Century on the heavy, steel, touring bike.
Whether I’m riding my MTB on the road or on trails I invariably work harder. On the road because I think I have an expectation that I should be going faster so I ride it at a higher effort level than my road bike. On the trails because they’re just hard work, climbs are often steeper than a typical road climb, and obstacles may require significant increases in effort in order to have enough momentum to attack them correctly.
I could be unconsciously searching for a more oxygen efficient cadence on the MTB, which is down around 70 rpm according to the above article. While on the road bike, where I’m able to keep my heart rate lower, I can more comfortably maintain muscle efficient cadences.
This would also explain why, when I climb a significant hill on my road bike and allow my heart rate to enter the red zone, I get better performance from my body if I drop my cadence a bit.
The real answer is probably a combination of all of the factors suggested in the thread. I can at least test the crank length hypothesis some time.