stevage

I've been trying to come up with a conversion factor between asphalt, dirt roads, fire trail, and singletrack, in terms of effort and time. So, for example, 100 kilometres of dirt road is about as hard as 140km of asphalt, maybe.

I'd be curious to hear what other people think the conversion factors are. Reply like this:

Good quality dirt road is ___% harder than asphalt.
Fire trail is ___% harder than asphalt.
Singletrack [if you're into that] is ___% harder than asphalt.

Rowan

Extrapolate the Audax Australia dirt series limits. A 100km dirt event has a time limit of 10 hours or a 10km/h average. Covers all the terrain you mention. But lots of hills might reduce the average even more.

Asphalt events at 100km have a limit of 6hrs 40min, or 15km/h average.

So track versus road = two/thirds. Maybe.

jamawani 

1.53892

SparkyGA

I figured that gravel takes me about 1.5 times longer than pavement.... The rest, I don't know

jbphilly

Each rider can probably establish stats for themself based on carefully controlled experiments. My guess would be something like, dirt takes usually 50% longer per distance/effort, but that really depends...some dirt you can ride on just as fast as pavement.

rodar y rodar

And some pavement is slower than dirt

Six jours

I think it depends on the bike. A race bike with 21mm clinchers at 130 psi is going to make every mile on dirt seem like two. But on a mountain bike, hardpack is going to be essentially indistinguishable from asphalt. So what kind of bike will you be using?

terrymorse 

I found this interesting table that gives rolling resistance for different surfaces. Granted, it's intended for industrial equipment, but the differences between values should translate to bicycles:

https://www.webtec.co.uk/tech/equatio...ble_of_rolling

According to this table, resistance of smooth dirt is about twice that of good asphalt. Sounds about right.

Western Flyer 

I assume we are talking about loaded touring. I figure half the distance on dirt and one quarter or less on single track. It's not just the speed being slower but I get beat up and need to quit earlier. Plus on unknown dirt roads I don't let it fly down hill, not knowing what dust pond, washout or washboard is around the nest corner.

jolly_ross

You should measure hours on the bike - two hours as fast as you can manage on pavement is as hard as two hours as fast as you can manage on dirt.

Unless you want to convert to dog years.

cplager

Don't forget that air resistance is probably our biggest enemy as most of the speeds we travel.

And then I find a huge difference between smooth roads and not-so-smooth roads and I gotta believe there's an even bigger variation of dirt roads.

It just very much depends on how and where you are riding.

LeeG

Depends on hills. Level packed dirt road might be 80% the speed of level pavement. Once things get hilly or technical you could be taking two to three times longer as there's no way you're going to descend with panniers on bumps at the speed you can go unloaded let alone paved road with a load. I could imagine ascending steep dirt or pavement at 4 mph but the descent speeds would vary a lot more. Easily 30mph on pavement, 15mph on packed dirt where washboard and dried wheel ruts are common to 6mph with technical maneuvering.

indyfabz

Yep. I picked my way up and down portions of a 20 mile unpaved road in MT a few years ago. Lost traction climbing the sandier sections. There were down hill portions (some steep) that were rough and rutted and even bare rock.

Water can also affect the riding. Later in the trip we did anotther 30 miles on dirt. The USFS had treated portions of the road with some chemical that made the road surface wet. (May have been calcium chloride. It was white, and at first I thought it was snow.) We were told by locals that it was done to to keep the dust down. The resultant layer of thin mud not only dirtied the bikes, it made for slower gowing than on the parts that were not treated.

John N

I asked a similar question about a year ago over on CrazyGuyonaBike. The consensus was that if an "average" day's ride on pavement was 60 miles for loaded touring while an average day on non-pavement was 35-40 miles. However, a lot of the people were using gravel and dirt roads on the Great Divide to make their point so a lot of climbing was used. However, this was born out over several months of riding, not just a ride on their local trails.

Using the above figures:
Non-paved miles divided by .65 approximately equals the number of paved miles, i.e. 40 miles of gravel equals about 61.5 paved miles.
[B]Paved{/B** miles times .65 approximately equals the number of non-paved miles, i.e. 60 miles of paved miles equal about 39 miles.

Like any average, this is just an average. Amount of climbing or descending, wind, compactness of road, etc. can play a factor.

Newspaperguy

Not all dirt and gravel roads are the same. I've been on some hard packed dirt roads which are almost as good as pavement but I've also been on some which are tough slogging through sand or loose gravel. Those roads are going to take a lot of energy to move slowly and cover shorter distances.

Near my home, there is a highway which has a gravel surface for around 50 kilometres. If it has not rained recently, my speeds on that road are close to what I'd reach on pavement. After a heavy rain, all bets are off. And in winter, I won't even consider riding it.

mmeiser

I always figured about 2/3 of the miles for dirt backroad. True singletrack is slower still. Maybe 1/2 the miles you'd get on road. However, it depends on how much you're carrying.

I have done backroad riding where my mileage was just as fast, but over the long term it averages back out as slower. For one thing, weather is definitely going to affect you more. I.E. rain turns dirt to mud. Because of this I put more flexibility into my schedule. I may night ride when the weather is nice (also because I enjoy it). I will ride double miles if it's a beautiful day. Generally I plan about only 80% of the miles I intend to do in a day so I can improvise on routes. Plot 80 when you can ride 100. If you get to far ahead you earn yourself a zero day. Take it when the weather is bad. Take it when you've stumbled on a sweet B&B, or when the weather's turned to crap.

I highly recommend lightening the load for backroad and especially off road touring. Every pound you carry is going to make travel twice as hard off road. Literally. It's not about speed, it's as much about enjoyment. Espcially true on rougher backroads.

Things I've found that makes backroad riding almost as fast as road riding.

1) carrying only 10lbs of base gear, down quilt, NeoAir or equive sleeping mat, bivy or tarp depending on the season, alcohol stove or titanium sheeting hobo wood stove. But you don't have to get so drastic. Every pound, indeed every ounce matters, just trim the easiest pounds first and go from there.

2) 40mm WTB Happy Medium or other 34-40 "race" tire... the right tire choice is huge. Maybe a WTB Vulpine 1.9" for singletrack, or a WTB Nanorapter 2.1" for even more sketchy terrain.

3) My titanium Fargo, though any Cyclocross even steel will work. (I also have a Surly Cross Check I love as well.) The agressive stance of cyclocross bikes is going to make them climb way faster in the hills, way, way faster then a Long Haul trucker which quite frankly is an absolute dog on the climbs. One thing I don't skimp on is my Brooks saddle.

4) go tubeless for off road... As for the tubless and race tires, it makes more sense to carry a whole spare tire (not that you need too) then carry all that weight in the spinning tire. You are no more likely to get a flat with a racier off road tire, especially if you go tubless, you're actually less likely to get flats as the sealing properties of Stan's Notubes is pretty awesome with high volume, low pressure situations. No question tubeless and racier tires make the bike climb faster, but more then that you can run lower pressures and get more speed and comfort. It seemed just as big a revelation to me as making the jump from 26" to 29'r.

Of course I dropped about 14lbs just in switching from racks and panniers to frame bags and a bivy roll. That's just the difference between dropping four waterproof bags and front and rear racks for a triangle bag, bivy roll, a gas tank, and super twinky seat bag.

I can't recommend studying up on bikepacking technique and ultralight backpacking techniques for off road touring.

BTW, if you were really looking to make decent time, there's these things called paved roads. They're usually graded as well. So... who cares how many miles you do off road a day.... other then to estimate your timeline that is. Just enjoy it, and yeah, bikepacking techiques and cutting weight will help you enjoy it more.

The axiom that best sums up the ultralight/bikepacking attitude is it's not about speed, it's about enjoyment. It's like going out for a sunday afternoon ride, but you can just keep going for days and weeks.

Bikepacker67

Everything is variable - and sometimes for no good reason.

We all have that "hill" on our travels.
It doesn't look like much. We've all topped bigger hills, that's for sure...
But something about this deceivingly gentle incline kicks our ***.

For me it was route 83 heading into the center of East Longmeadow, MA - just past Countryside Store.