tyrion

According to Strava I hit 40+mph every now and then on the big downhills. My top gear is 48-11.

djb

you lucky son of a gun!
in that case, go with the top gear that brings the most pleasure. I like riding in mountains for the payback downhills after all the slow slogging up.
I really love going fast downhill, but when touring, I really don't mind losing out some top end for lower gears, and so often find even a slight headwind keeps my terminal speed not much more than 60kph, so spinning out a bit over 50k is ok by me.
But unloaded, I want to be able to spin up to at least 70kph (45mph) around here though I rarely get downhills that long, so thats why its not a big priority for me.

pdlamb

I've got a couple hills near me I can reliably hit 40 mph. But I'll normally stop pedaling around 25 mph near the top and coast. Only once have I been lucky enough to catch a really good tailwind while loaded on flat ground, and I thought I was in heaven holding 25-28 mph for 10 miles.

Similarly, while I might win the lottery this week, I'm not going to spend a lot of effort planning for it.

mstateglfr 

You are absolutely correct, and if you spun at 110, you would go even faster than 37mph.
What % of tourers ride at 100rpm though? What % of enthusiast roadies even ride at 100rpm?

I see people at 60-75rpm when they are rocking their touring bike with bags all slapped onto racks. I can honestly say I have never seen someone spinning at 100rpm while touring.
To be clear, I dont mean spinning for 1min, I mean actually riding like that for miles on end. I dont see that cadence when they are pushing a huge gear and I dont see that cadence when they are cruising along on flat road.

Neil G.

I do, and not due to any conscious effort, or history as a bike racer, it simply seems to be the cadence that my body discovered to be the most-efficient way to cover long distances while touring. Every few months on a straight stretch of road I'll get curious and start the timer on my computer and count out strokes (computer doesn't have a cadence function), and "yup, still ~100". My wife, who learned to ride a bicycle at age 35, and thus is still such a "newbie" that she has trouble making tight right-hand turns, does 90-95rpm naturally (admittedly taking some influence from me). I know we're certainly at the high end of the curve, but I haven't felt like an extreme outlier when observing other touring cyclists.

Our cadence then explains why we have 40-30-22 cranks, and almost never use the 40t ring (I think my wife has literally never used it). So if 40t is already a bit a of a waste, anything bigger than that definitely would be! A 30t big ring "limit" and 90rpm cadence equates to ~20mph. We frequently go faster than that, regularly into the high 20s/low 30s, but that's coasting down hills, where any effort to push faster than that would be largely burned up by strong wind resistance at those speeds, would take away from our ability to enjoy the canyon we're flying down, and would be better saved to be spent more-efficiently on the inevitable uphill following that downhill.

So yeah, as someone who could get by fine with a 30t big ring, the idea of "downgrading" from a 50t to 48t sounds like a couple of empty-nesters downsizing from a 17-bedroom house to a 15-bedroom house. Like, I guess that's technically more-efficient...? Of course if you're a slow-cadence rider, the 50/48t might be useful, but then at 60rpm the 26t->34t low-gear combo becomes the useless one, as you'll be spending more energy to keep from falling over at 3.7mph than you'll be directing up the hill.

Yup, I also hit 40+ mph now and again. But that's gravity doing that for us, not our legs!

Depending on the totality of your setup, that could work, but I definitely had trouble with a 36T cassette and the M772 derailleur. It's unfortunately not a very robust combo (whereas M772 + 34T hasn't had any issues). The basic issue is that in order for the derailleur guide pulley to clear the 36t cog, the B-screw needs to be adjusted such that the Shadow derailleur design leaves a huge gap between the guide pulley and most of the middle cogs, which results in poor/non-existent shifting amongst those cogs. My solution was to "downgrade" to older Shimano derailleur technology (RD-T4000), and now the gap is much closer, and the shifting is far more robust. You can read all the gory details in this thread.

tyrion

It's both. Mostly gravity, but I wouldn't hit 40mph without pedalling.

Yan 

60-75 rpm is bad for your knees and will cripple you later if you ride long enough like that. I don't suggest it, but your body is your own to abuse, personal responsibility.

I ride with a cadence meter and never drop below 80. I'm over 100 rpm all the time.

mstateglfr 

60-80rpm is the cadence range that covers almost every study/article I have read where the subject is amateur cyclist cadence.
70rpm is not inherently bad for your knees. It has been consistently shown that you use less oxygen at lower rpm like that when compared to high rpm(95 up). If the cyclist finds they need more oxygen, then a slower cadence is perfectly fine.

A study showed sit and spin produces the best mix of lower heart rate and higher power when climbing compared to standing and mashing. Standing produces more power, but a higher heart rate too.
Another study took a dozen+ experienced cyclists and had them perform multiple 5mi TTs. Low cadence produced more power and faster speeds.

Reality is that there is no 'best' cadence for everyone. Studies cant even fully agree on something like fast twitch vs slow twitch to a specific cadence type. With that said, it does appear that more often than not, fast twitch dominant cyclists naturally spin at faster speeds. This then plays out just like it would in distance running or other endurance sports- slow twitch dominant cyclists then perform better over distance and time. <--again, not universally accepted or concluded.

High cadence has proliferated as 'the best' style because pros are able to spin at really fast cadences. Thing is, they also produce a lot of power at those really fast cadences. Thats not what mere mortals do, so why would pros be emulated in their cadence? I cant spin as fast as Froome, but I also dont look like a stereotypical lanky muscleless alien.



Contrary to your claim, there is absolutely nothing reliable that shows people with 70rpm cadences are more likely to develop knee problems. Perhaps something like 40rpm while also holding a fast mph will lead to knee pain, but 70rpm for a random recreational cyclist?...nah, in general that will be fine.

Yan 

Let me throw this question back at you: what % of tourists ride at 37 mph? To be clear, I dont mean 37 mph for 1min, I mean actually riding like that for miles on end.

Follow up question: what % of tourists ride at 37 mph for miles on end with a 60-75 rpm cadence?

Cycling at low rpm puts more force on your joints than high rpm. If two people are pushing out the same power, but one of them does so at 60 rpm and the other at 90 rpm, then the slow guy has to push out the same work in two revolutions that the other guy pushes out in three. Therefore, each individual push must be more forceful. It's a simple mathematical relationship. That's assuming you have the cardio to support a high rpm. Most competent cyclist do.

Tourist in MSN

When biking, I consider the word catastrophic as meaning a bike that becomes dysfunctional or could cause injury. For the several years that I had a couple bikes where I had more chain than the rear derailleur cage could take up, I was reminded I was in one of the do-not-use gears (smallest chainring, one of the two smallest sprockets) when I could hear the chain between the crankset and the lower jockey wheel rubbing on the chain that was wrapped around the upper jockey wheel, the noise of chain rubbing on chain was a clear notification to shift. But the bike was fully functional after I shifted out of that situation and there was no catastrophe. I avoided those gears, but it still happened a few times.

Generically, I would never design a bike system like that for a customer, some customers will do things wrong if at all possible to do things wrong. But for my own use I saw no problem with it since I tried to avoid those gears anyway. I later changed the big ring to a smaller ring to convert to half step plus granny, those two bikes no longer have too much slack. In this case I just advised the OP of the possible situation.

And running too little chain instead of too much could cause a nasty problem if you accidently tried to shift into big ring and big sprocket. That could be catastrophic. Several years ago I was out on an organized ride, there were several people gathered around a bike on the side of the road, I stopped to see if any assistance was needed. Over a half dozen people were amazed that both front and rear derailleurs could break at once, as both refused to shift. I pointed out that the chain was on the big and big and was so tight, of course nothing worked. They got the wheel out of the frame and put the chain on a smaller cog, things worked after that, although the rear was a bit out of tune after that. A bad way to start a century ride. The rider had his bike tuned up for that ride and a mechanic used too short of a chain when he replaced it just before the ride.

Sorry for the delayed response, was out of town for a couple weeks.

Tourist in MSN

Thank you for your post. I was unaware of such studies. No, I am not asking for citations as I would likely never get around to reading them.

But I can say that I find that I get about the best power around 72 RPM, often ride in the 66 RPM range.

I have below normal range for red cell count, iron level, EPO, etc. Virtually every medical chemical test shows I am below the normal range for oxygen carrying capacity, thus am a low wattage rider and will always be a low wattage rider. Your comment on oxygen consumption is quite pertinent for my situation. And it does explain my preference for a lower cadence.

I know a guy that spins his crank like a humming bird, but he was born that way.

I have bad knees, I have not stood on the pedals for over a decade, am perfectly content staying in the saddle when power is needed.

staehpj1

I rode the ST without a high top gear. I expected it would be an issue at times. What I found was that in practice on long hills I could usually breifly spin a super high cadence at the top and then coasting would carry a surprising level of speed the rest of the way down unless I needed to brake for turns in which case I'd have to do a quick short burst of very high cadence again.

It might not work as well for all conditions, but I was pleasantly surprised that my thirst for fast descending was satisfied and I never missed the top gears. My rather limited gear range for that trip was 25.1 - 87.8 gear inches. The somewhat limited range at the low end was okay as well. I was packing very light (14# base gear weight) and the route was the Southern Tier so it was the least mountainous of the common coast to coast routes.

Yan 

I went with a 1x12 drivetrain on my most recent build. 34t chainring front, 11-50 cassette in the rear. That works out to 18.5 to 84 gear inches. At 90 leg rpm the top speed is only 22.5 mph (36 km/h). That's all I need because above 22.5 mph I have zero desire to continue adding energy to the bike. It's fast enough and I'm letting my legs chill. I'm touring, not racing. The more time I can spend coasting the more happy I am.

You can also get wider range 10-52 cassettes for 1x12 systems, but those require special hubs which reduces repairability in developing countries. Sram's 11-50 cassette uses the old Shimano HG hub standard, so if something breaks you can keep using your wheel, slap on any 8 speed or newer el cheapo mountain drivetrain and be on your way. Microshift makes a 12 speed bar end shifter that's convertible to friction.

Xavier65

On my old tourer, I had 30/42/52T chainring (Shimano FC-2303) and 11-36T 8cog cassette.
I needed to do a tour via 4 mountain passes, so I swapped out the 30T with a 20T super-granny.
This worked fine, although 10km @ 11-13% is pretty hard work on a fully loaded tourer even so.
One doesn't use large front & rear, so the chain should be just about long enough to stretch, but no shorter (to avoid catastrophe).
One can use the lowest 4 gears no problem. The chain becoming diagonal, gear 5 begins to catch on the middle chainring, but is still usable, Gears 6,7,8 are unusable (irrespective of low chain tension). However, their ratios overlap with those of the lower gears on the centre chainring, so no gears are lost.
After the tour, I changed the 20T to a 22T, which improved gear 5.

I find the use of a granny chainring and 4-5 low gears is far superior, to the alternative of enjoying all 8 gears on a modestly small chainring.

Xavier65

Oh, there is another way of obtaining wider gearing without changing your triple 9 speed setup.

Install a Sturmey-Archer CS-RK3 3 speed hub.