I another thread I asked about the Sierra Cascades (ACA) route. Contributions pointed to the fact that this is a very difficult course.

What tools do you use to (objectively) assess a course difficulty? At this point I know about climByBike. Great on a per-hill basis, but not so much to, let say, compare the Sierra Cascade to the Pacific Coast, or to fine-tune a course to avoid killer-hills.

At this point I intend to map on Google Earth, examine the elevation profile and zero-in on what may look like places we'd rather avoid. The problem is that a 100km-long 5% hill looks like a monstrous obstacle but in fact is much less problematic that a series of short climbs at 15%+.

hmmm.... I suppose that my question is something like:

1. what constitute a practically unsurmountable obstacle?
2. what is the most convenient way to make sure that there is no such road-block on a (lengthy) planned course

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UPDATE
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I stumbled across what seems to be the best calculator for my purpose. It relies on wind, gradient and several other measures to compute a flat course equivalent. It highlights the relative importance of headwinds and maximum gradient in making a course difficult. For example, the Sherman pass (H99) climbs 1627 meters over a distance of 24.5 kms. According to the FLA calculator, these 24.5 kms are equivalent to 87 kms on a flat, windless course. The climbing effect is equivalent to headwinds blowing at 50 kms...

If the same climb were of a lower gradient (say, spread over a 80k distance), the flat windless equivalent would have been 125k. With 50k headwinds, the FCE becomes a mind boggling 365k.

As good as this calculator is, it is still not trivial to solve the basic problem of carving up a route in FCEs of a given length. (If someone is interested in giving a shot at it, let me know.) But it is pretty good as it is.

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UPDATE 2
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Computing the flat course equivalent (FCE) may be interesting, but (1) it would take forever to do this with actual data (2) two climbing courses may have an identical FCE, yet one course could be impossible to ride if it rises too abruptly, beyond the gradient that a loaded tourer can negotiate.

An interesting calculator computes the speed at which a rider will progress given power (expressed in watts), weight and gradient among other things. An average rider i said to be capable of sustaining outputs in the 100-200 watts range. It is also possible to use the calculator to infer wattage. 100-200 + bursts at 300 fit my experience quite well.

Armed with this, we find that at 200 watts, a rider weighing 75kg, riding a 13kg touring bike loaded with 20kg of supplies will travel at 27 kph on a flat course, and at 5.9 kph if the gradient is 10%. 5.9 kph is the lowest ratio that my drivetrain can deliver (26x34) at the sluggish cadence of 64. If the gradient becomes 15%, achievable speed drops to 4.1 kph -- meaning either dismounting or increasing the effort to an unsustainable level. These limits fit very well with my experience and allowed me to look at the impact of (bike=supplies) weight (negligible) and headwinds (also negligible) on course practicability.

Bottom line for this first part of the "solution" is that the maximum long-run gradient that I can practically climb is 10% max, with short sections of 15%.

Then it becomes a fairly simple matter of inspecting a course for sustained high and maximum gradients. The best if not only way to do it right is to use data triplets (lat-long-elevation) from GPX files and compute point-to-point gradients. Routing softwares aggregate these date coarsely and therefore provide "optimist" gradients.

The easiest way to generate the GPX is by using gMaps to create the route (most routing sites use Google's API anyway) in conjunction with gpsVisualizer. Copy and paste Gmaps' URL and choose "add DEM elevation data". Convert and plug the resulting data in a spreadsheet (which will require some text processing). Use this formula to compute distances, divide elevation differences by point-to-point distance and you'll obtain the point-to-point gradient.

A typical course will contain thousands of gradient, making it much easier to anticipate killer hills. Charts may look like (elevation in blue and gradient in red):



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UPDATE 3
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I now think that I have what was looking for -- I can generate (conservative) time estimates for a course, calculated by taking the average gradient at each kilometer.

1. I used this calculator to generate speed estimates at various gradients (from -10% to +10%) for a loaded touring bike on which the rider applies 100W of force. Estimates run from a low of 2.8kph at +10% to a high of close to 80kph, that I capped at 50.

2. I generate the course profile (gMaps or Strava) + GPS visualizer and plug the lat-long-ele data into a spreadsheet, which computes average speed and expected riding time at each km.

Estimates are quite instructive. For exemple, the Wawona-> Lee Vining segment of the Sierra Cascades is forecast at close to 16h even though it is less than 160km long. Those I did for segments I am familiar with are reasonable. If anyone wants more detail on this recipe, let me know.

Drive it first. The worst hills are often tiny things of no consequence that go straight up. If I was still young and healthy, I wouldn't want to strip the adventure right out of it. These days there is so much information out there you can at least get people to comment on just about any route. One thing that doesn't work is asking locals who probably don't cycle.

In many cases it might still be preferable to do the steep route if it just had one or two bad bits. Walk them, or maybe find a shuttle. I wouldn't give up hundreds of miles of Pacific breezes to go inland among logging trucks and clearcuts.

That is something I don't recall anyone ever mentioning that they did. Do you do it for most trips? Even for long tours?

BITD before the internet, Google maps and Strava, we used (free) gas station road maps to plan routes. The ones from Rand McNally were the best because they were very consistent in how roads were mapped, related to their type and traffic load. We judged terrain by clues like rivers, roads crowding into what seemed like a narrow valley or pass, how wiggly a section of road seemed to be, etc. Many of actually got very good at this game and had a good sense of what to expect when we got there.

These days there are so many sites that show elevation profiles, and you can often get detailed profiles by mapping only a short section of your route which may be suspect. You can also use Strava to get a sense of where the locals ride (don't ask me how, I don't Strava). Otherwise use the same types of clues we used back in the days of paper maps.

climbs and such are one thing (and not insignificant) but considering you want to do trips with your kids, another super important factor is how travelled a given stretch of road is, and or what sort of shoulders are there? Is there a lumber mill nearby so you might be dealing with loads of lumber trucks, camions des pitounes, or dump trucks--this sort of thing. For me, this is the stuff that is harder to ascertain from looking at a map, but at least nowadays we can get pretty good info about routes already toured on by looking up stuff on sites like CGOAB.

As for difficulty as in steepness etc, all I know is that when I did Gaspe in 90 or 91, I got some really unpleasant surprises with some killer killer hills that were just murder getting up, and dealing with too high gearing, too much stuff. Looking at maps, I had no idea some sections were so bad. A few summers ago when I did Montreal to Boston, I didnt take the time to go over google maps or whatever for climbs along the route, but I think from more experience at looking at a map and figuring that a road would have a much higher chance of being steep due to the the layout of how the road went.

I dont know if its still the case, but Michelin maps in France 20 years ago had those neat little arrows or chevrons on climbs and descents to give an idea of how steep it would be. One chevron=a bit steep, 2=more, and 3=pretty darn steep. Really handy for giving a heads up. Today, realistically I see reading trip reports and such as the most reliable way to see how a route is, if not it comes down to doing the computer thing, or back to reading maps in a way to see how a road follows rivers and such, and or being lucky and seeing maps that show elevation and stuff, and or topo info to a degree.

check in at America's Bicycle Travel Experts | Adventure Cycling Association for advice and take a good look at crazyguyonabike You'll get a lot of experienced people at both sites.

Topographic Maps .. Once you learn Map Reading You can See the Shape of the land ..

I used the University Map Library , a Geography department resource, to research Routes ..

So I didn't have to Buy them.. they stay in the room at the Uni..

If it's an ACA route read the Overview, Terrain, and Logistics tabs on that route. Then go to crazyguyonabike.com and click on journals>categories>routes to find journals for those routes.

This may not be objective but combined with the other methods you have this might give you additional useful info.

With a six year old I might be looking a lot at rails to trails...

yes yes...

This past Summer we relied on gMaps to route us, hiking in Europe. As good as Google is, it sometimes doesn't work. We ended up quite a few times on abandoned forest roads that have become impassable. Whenever I could, I would scan the itinerary with satellite imagery. Worked quite well.

WRT the Sierra Cascades -- This is all very preliminary and tentative. One great thing is that being in the USA, the amount of information is impressive. G Streetview has lots segments covered.

this touches on the whole topic of how much research to do for a given route before you go. I certainly appreciate knowing that there will be X amount of climbing between point A and B, but perhaps because I have used paper maps so much in the past, I find I have a reticence to using google maps and such to overdo pre-trip research and look at how roads look.
"Over do" is a broad statement, I certainly find google maps streetview and such as great resources, I just question how much research and exact details is necessary. Of course, when saftey issues are at hand (narrow road, windy, lots of traffic etc)--more info is always better, and especially so with travelling with children and perhaps a towed trailer that can be wider.

This is not being critical of your trip planning here Gauvins, but more a general questioning of how much is too much and can take away from some of the "wow" factor of discovering places first hand, or perhaps a better way of putting it, not having a preconceived view , photos etc, of how a place looks before you move through it in person.

I guess I bring this up because one aspect of bike touring, or just biking in general, that I still love, is that sense of adventure and discovering things as you go along. I figure there is a good balance of knowing a certain amount of things, especially when dealing with safety, vs a bit of winging it and taking things as they come and getting that "wow" moment of seeing things for the first time.

**Just saw your addition of that florida cycling calculator--didnt look at it for more than 5 seconds, I guess if it can be a help, great. My first reaction was that it seems like a lot of work, but I guess for some dubious sections, it could help.
My feeling is still that looking at a trip with so much micro planning is not my cup of tea, too much techno and would detract from it--but thats just me.

If you use this, I'm sure others would be curious to hear how it actually works. Thing is you will really only know after doing a trip how and if and to what extent it was a help.
cheers/salut

I just tried the climbybike site and I am not sure it is helpful for me. A friend and I completed a three night trip in the Jocassee Gorges area in South Carolina on forest service roads. Using the climbybike I mapped a 0.32 mile (.5 km) route that I know to be extremely steep. The climbybike reported only that the average grade was 9.5% and failed to show a nasty section with a grade of about 30%. Maybe I did not use climbybike completely and missed some options.

A problem with many of these mapping sites is that grades are calculated over long distances so difficult sections may not be well identified. I tend to use Maymyride ( Bike Maps, Cycling Workout, Biking Routes | MapMyRide ) because it provides a graphic showing elevations and grades. But it also suffers from averaging grades over long distances, so to learn of the difficult sections one must examine short distance sections in areas that could be difficult, hence my option for the .32 mile routing. Attached is a screen grab showing the elevation and grade profile of this short section.

For long trips -- hundreds of miles or km, I don't know that I would be concerned about grades especially if riding paved roads. I know that I strongly dislike grades over 15% for longer distances, or many repeated sections with steep climbs. For off-road touring, such grades can be commonplace, so I tend to look carefully now at mapmyride elevation profiles before determining whether I join a particular off-road tour. When I see repeated climbs of 25% or more, I know that won't be an enjoyable trip for me.

As you wrote earlier, it would be nice to have a mapping program that would flag areas with grades over a certain percentage. I would like to be able to plot a route over maybe 50 to 70 miles, and have the program flag sections with grades over 15% or whatever grade one chooses. That would be a potentially helpful feature for me.

for me the question is where is the gradient data coming from? Just seems to me that it is unrealistic for accurate info to be for all kinds of roads. I admit this sort of detailed planning doesnt appeal, but I just wonder how accurate things are, and how much time spent doing this compares to using other resources.

As pointed out earlier, Contour maps can show detailed info including gradients. Once you learn to read them it's as easy as pie. They're available on line to look at, but you have to pay for hard copies. The only issue is scale. If you're doing a long ride, you'll need to piece together a bunch of maps.

OTOH, you might reserve contour maps for those places you have a reason to believe might feature steep hills.

Climbs and such can't be trusted when you are using any internet referenced mapping source, only your eyes will tell you the truth.

An example is well deserved to show what I'm talking about.

(unnamed) - Franklin County, KY

I rode this climb back this summer. I was expecting a real butt kicker climb. I downshifted to a 30x15 and ended up climbing this thing like it was nothing. I rode 11 mph up the entire climb. Oh yeah, to make matters worse, where the map shows the first drop occurs(just under 200 foot drop) there is no drop. It's a solid climb straight up the top. The map data sucks. I wouldn't even come close to calling this a 15-18% grade climb by a long shot, maybe 12% pushing it.

Now to make matters even worse I got up top of the hill and stopped in the convenience store and saw the Frankfort newspaper was saying the route I planning to take as I pedaled away from the capitol building was about to close...50 minutes later. I got into Frankfort and made my way to the capitol building and after going around the capitol I started to leave and saw the closed sign and also saw the road I had been planning on heading back up to the highway on...a nice steep climb. I thought...sweet, I'll avoid that climb. I had a road straight in front of me and decided to take it hoping it would angle me up at a shallower angle and allow me to cut back to the original route. The original plan was to take Lafayette Drive. That climbed I would guess is 18%+ grade.

(unnamed) - Frankfort, KY

I took Shelby St and had a decent 10-12% climb up the first part before the 90 degree bend. There was a bit of break, as I remember, right near the curve in the road and I downshifted to the 30x15 and as I got around the curve I saw the steepest road I have ever seen to date. I was glad I was riding in that low of a gear and was only making 4 mph up the hill. It was easily over 20% grade. The map data makes you want to believe it's only 12% and that it isn't as steep as the climb north of Frankfort that I saw an hour or so earlier.

The map data was horribly flawed. Heck I even saw bad mileage data both around Nashville and New Orleans this summer. You can't trust the map data and especially the way it wants to calculate the % grade.

I just know a climb is coming and don't worry too much about how it compares to another climb. The way you feel at the time in question can make a big difference between and easy climb and a climb that is utterly miserable. Trying to compare one hill to the next can only be done at the time in question and I wouldn't waste my time trying to do it without being there/riding it.

Ya, grew up using contour maps with hiking, but my comment was directed at that website. Re contour maps, I've never bothered to try to get access to specific maps when planning trips in the past, and just used road maps. More of an interest of lack of interest to get into that detailed stuff, but have toured in hilly areas a fair amount so with the load I generally take, I know I'm OK with regular roads, so don't obsess about specific gradients.

We do it for shorter, local rides.

Your first example is exactly like a road near Cedar Grove IN. It's been widened and cut into the cliff some years after the Google Map data.

Here's your map on Terrain View. Heading south, the road went up and over the hill, then up again on the side of the creek valley.


And on Street View, which shows the road cut. So Google has elevation data from the Street View automobile, but hasn't updated it's maps.



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I know of a few other climbs around SW Ohio that are way steeper than the maps show. These are about 200 to 300 feet high.

I sometimes look at Strava segments to see what was recorded by GPS. But Strava seems to keep the original ride for a long time, even if it's obviously wrong. They don't average all the different recordings. So the actual grades on strava can be hit or miss.

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Roads that angle up the side of a steep mountain can be way off on their local grade estimates. The mapping software uses known elevation points on the mountain, and tries to estimate exactly where the road surface is. If it's too high or low at that spot, it'll affect the local grade percentage.

I'm going to answer this question with Randonneuring in mind rather than Touring. When I'm touring, I generally just ride whatever is there and make decisions about route options on the fly.

In Randonneuring, there is a seemingly very generous 15 km/h minimum speed. "Seemingly" because that includes all rest stops, and if you're not a particularly fast cyclist, and then take a nice little lunch break in the middle of a ride, all of a sudden maintaining 15 km/h can be challenging.

When I lived in Manitoba, I never worried about the difficulty of rides because the difficulty depended on the weather rather than the terrain, and who can predict the weather? Winds that slowed me down below a 15 km/h rolling speed were rare, and there were often just enough tailwinds to push me along at a faster speed to make up for it.

When I moved to Alberta, there was more climbing, but the climbs weren't steep ... and I can do a few gradual climbs in a ride without it adversely affecting my time.

Same with Victoria (Australia).

But then we moved to Tasmania, and the climbs became frequent and steep, and all of a sudden ... I couldn't maintain that 15 km/h minimum speed. When you drop to 4 km/h going up hills, it can be hard to make that up again. But it was hard for me to judge routes ... what was a reasonably flattish route which I might be able to do, and what was too difficult?


Then about a year ago, I came across this calculation in the Road Forum:

Elevation in metres/Distance in metres * 100

So ... if a route has 500 metres of climbing over 40 kilometres, that's 500/40,000 = 0.0125 * 100 = 1.25

For me, anything under 1, is basically a flat route.
Between 1 and 1.5 is hilly, but manageable.
1.5 to 2 is quite hilly and very challenging for me. Might be touch and go whether I could finish within the 15 km/h minimum.
Over 2 ... too difficult. Out of my range.

So my route to work, if I were to cycle to work, is 275 metres over 15.2 km ... 275/15200 - 0.018 * 100 = 1.8. At this point, that's just too challenging for an early morning ride.


Anyway, that's how I calculate the difficulty of randonneuring routes, and I sometimes I use that calculation for tours and recreational rides too.

(Very) good and important point.

1. I certainly do not have the reputation of being risk averse. Quite the opposite. This thread being a case in point where I am warned that the SC is very difficult and unlikely to be suitable for kids. I am used to this. It is too early to tell, but I have the strong feeling that we'll do it (Northbound, probably starting at Lake Isabella, but it really depends, because the Western section of the Mohave is appealing as well. We are used to being outdoors under blazing sun in temperatures above 35 celsius. This desert does not feel threatening to me, but may not be the best way to start a trip if there's a heat wave. I will add that crossing LA by bike sounds great to me, too. We've walked across the City of Toulouse (population 1M+) with two donkeys in tow etc. etc.)

2. I am quite well travelled and used to "winging it". I am used to leaving home for several weeks, packing time zero-to-the-airport being counted in minutes. Yet I hate wasting time searching for accommodations so yes I tend to know what the options are and am often booked ahead. Always with the understanding that a booking is not binding (well, you may have to pay for a roof that you will not see, so what, as long as it is not frivolous).

3. OTOH, (a) I learned to prep for the worst in the context of sailing; (b) our bunch has young kids that adapt well to many/most situations, but I have responsibilities towards them. We've never bought packaged tours. I derive pleasure in planning.

4. Over preparing... maybe there is a risk. But let me suggest the following analogy -- if you go the a museum of modern art, without having any artistic culture, I would venture to say that you will not appreciate it that much. Learning before going to the MOMA isn't detrimental. Unless you purchase the catalog ahead of time, check the items you wish to see in sequence, go on a rainy Sunday afternoon and then make a fuss because it is packed with visitors... (I remember reading somewhere that one should read tourist brochures prior to leaving, in order to know where not to go

5. There will be a time, I hope, when we (my wife and I) will be able to leave from the front door, without any plan. Serendipity. Yep

From the Original Post:
Interesting. It's got to be a complicated problem, since even flat roads usually have some small hills and may have headwinds. I generally use "200 feet of climbing = 1 extra mile" as a very rough estimate, but ignore it unless the climbs are well over 1000 feet high. That matches up fairly well with the calculator's blog page chart, showing a range between 1000 feet=3 miles for very strong riders, down to 1000 feet=almost 10 miles for weaker riders.

Difficult climbs:
If I have to stand up on the climb, that's going to make it a lot harder. With low enough gears, I can stay seated on an 8% grade quite easily (with no touring load!) 12% and over is going to be a strain for me. For really steep climbs, say 18% or more, I'd want to keep the day's mileage way down. (I can do steep or long miles, but not both at once.)

Hi bikenh --

I was curious to compared grade estimation from ridewithgps and mapmyride. Try plotting your two routes in mapmyride and I think the grade estimates more closely approximate your verbal description. This is especially true for the tanglewood dr route plotted at .36 miles in distance where an upper grade of 21% is shown. Attached is the graphic. I think the accuracy of the estimate depends on the mapping source and also the length examined.

yes yes, if a route climbs 500 metres over 40k, there is no problem whatsoever. But if the route is flat for 35k and then climbs 500 meters, including a grand finale at 25% gradient, kids will cry (and parents will bite their lips :.

Two things -- first, you are not the first saying that the Rockies are not as difficult as they might appear -- the "usual gradient" is quite reasonable.
Second -- but I was not expecting to read several members of this community warning me (in the SC thread) about the course being difficult (heat + climbs). So I am trying to put a number on these statements.

Thanks for your input.

If you map the route out using Google maps, and the bicycle option, you'll get an elevation profile. If the elevation profile indicates that the route is flat for 35 kilometres, and then gets really hilly for the last 5 km, then do the calculation on the last 5 km.


My comments about Alberta did not necessarily include the Rockies. The Rockies make up a small part of Alberta. Nevertheless, the roads through there are pretty gradual ... steepest you'll encounter is a 12%.


What is the route you're considering?

I also find it helpful to ride hills in my local area which are similar to what I might encounter. So if I know that the steepest hill will be 12%, then I'll ride a 12% hill or two in order to get a feel for it.

Very interesting comparison. I was guessing at the time 20-25% grade. I knew it was way over 18% as I've ridden Mt. Ascutney in VT twice and it has an extended stretch of 18% and averages just under 12%. I know what 18% looks like as I drive up the road several times a year helping out the hang glider pilots around the area. That's why I was shocked to see it rwgps come up with such a low % being shown for Tanglewood Drive. I'm not used to looking up a stretch of road like that...LMAO

Generally it doesn't really matter but when you run into instances where your going to hit big % grades climbs it can make the difference...like a couple of other people have stated. It gets worse when you think you don't have much of a climb but you come to find out in reality that you do because the map data is incorrect. I would have guessed the map data would have been the same between websites and the interface was set up differently between them. I thought they all dropped back to using Google maps.