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Messages - mathieu

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Routes / Re: Great Divide Route, north of Ashton ID
« on: February 23, 2015, 06:31:58 pm »
The loose soil on this Idaho rail trail is cursed even by MTB riders with 50 mm wide tires. Fortunately most of it can be bypassed on a parallel dirt road in a distance of less than 1 mile from the rail trail,  that has a reasonably good surface. See the map at the bottom of my journal page for this stage : (zoom in for details; blue is rail trail).

Gear Talk / Re: New Rider who needs advice on tires
« on: February 22, 2015, 12:14:02 pm »
Instead of the Schwalbe Marathon Plus, I would go for the the Schwalbe Marathon Racer. Take 700x30c if your bike can handle it. It is 395 gram per tire  instead of 750 gram. You feel this difference when you are speeding up. Don't be afraid of an occasional flat. It usually happens only every 1000 miles or so, unless you enjoy riding on interstate shoulders full of glass and steel debris.

Gear Talk / Re: Tubus Lowrider Racks for GDMBR?
« on: February 22, 2015, 09:56:32 am »
You will have no real problem. In 2010 I did the GD route south-to-north using a Bob trailer. Two companions used low front panniers. Look at the attached slide show to see the clearance of the bottom of the Bob and the panniers of my companion. The show will probably raise your appetite further to embark on this beautiful route. Several pictures have been published in an issue of the Adventure Cyclist one year ago.

General Discussion / Re: Great Divide Northbound Questions
« on: January 18, 2015, 11:17:50 am »
I wouldn't start before half of May. In the north of New Mexico the route goes over 10,000 ft (Polvedera Mesa), over 11,000 ft (Brazos Ridge) and almost to 12,000 ft in southern Colorado (Indiana Pass). You can bypass each on pavement, but it would rob a lot of the route's main beauties. Also many passes in Montana and British Columbia don't clear before mid-June.

From reading many blogs and my own experience, I sketched a chart showing the time windows for going S-to-N and N-to-S in . Of course this is not rocket science.

Routes / Re: Great Divide Rooseville, MT to Helena, MT
« on: August 30, 2014, 09:01:10 am »
Carla, it's an indulgence to go back to the maps and refresh fond memories of those towns and trails of the Great Divide route.
I went through all maps and added all paved sections on the main route longer than 5 miles. I came to a surprising total of 673 miles, i.e close to 25% of the total route!
That old estimate of 5-10% on pavement (also in Wikipedia) is wide off the mark.

Routes / Re: Great Divide Rooseville, MT to Helena, MT
« on: August 29, 2014, 06:44:51 pm »
Adventure Cycling clearly has an unrealistic view of the percentage paved, both for the whole GD route and for this particular section from Roosville to Helena.
In this section roughly 25%, about 90 miles in a total of 370 miles, is paved. The detailing by Iowagriz is also what I remember.
For the total route it is more likely between 10-20%.

I recommend to delay the start, if possible, to mid-May for more agreable overall temperatures.

Flying to Washington-Dulles airport, I rented a large car (small minivan) to transport my boxed bike to a hotel in Williamsburg. A few days later I returned the car to Dulles, took a shuttle to Washington-DC and the afternoon train from Union Station to Williamsburg. This eliminates hauling an unwieldy box and other bags in shuttles and trains. It even allowed a few hours of carefree sightseeing in Washington. Returning a rented car was much less expensive than dropping it in Williamsburg.

Routes / Re: The Great Divide - question
« on: July 29, 2014, 03:34:18 pm »
Depends on how fast you go. Have a look at the chart in . If you can do the route in 1 month (i.e. about 100 mi/day), you may get to the US-Mex border, but if you need 2 months probably not. But this is not rocket science; every year is different.

Routes / Re: Geronimo Trail
« on: June 30, 2014, 07:53:58 pm »

Your start is 4 days before the Grand Depart of the 2014 Tour Divide race from Banff. Even at 100 miles/day, you will probably be overtaken after 7 days by the frontrunners. On you'll find the latest info about snowpack. I saw a cryptical post recently from Matthew Lee himself. He has eyes and ears everywhere on the GD. Follow that link!

General Discussion / Re: Tour Divide Race 2014!
« on: May 09, 2014, 07:28:05 pm »
There are 40 odd pages about TD 2014 waiting for you to read at

Gear Talk / Re: Making wheels stronger with a mixed spoke pattern.
« on: April 21, 2014, 03:58:53 pm »
In the end, for touring use a conservatively designed wheel built by a good wheel builder.  For most touring applications you should not use radial spoking.  Don't use low spoke count wheels, do use a good brand of spokes in a conservative pattern that doesn't require a tensiometer to build.  Use strong rims.  Make sure they're in good repair before starting your tour.

In June, about 120 racers will start for another edition of the Tour Divide race, 2700 miles from Banff-Canada to the US/Mex border. I guess only a few of them will have wheels that fit your recommendation. All of them will have loads that are substantially less than most tourers, probably between 15 and 30 lbs, but their pace is surely much faster and the dirt roads are much rougher. About one-third of them uses rigid forks. I guess for all of them the dynamic  impact on the wheels is much harder than for touring, whatever the load. The race rules prescribe that in case of a mechanical defect, the racer has to go back to a commercial bike shop; no private assistance or forward movement along the GD route is allowed. From the past editions, I do not remember any wheel defect. If it were a serious risk of modern MTB wheels, it would have shown.

What I want to say: there is nothing wrong with being conservative in chosing wheels, but you should be aware that your bike is probably heavier then needed!

Gear Talk / Re: 11-32 vs 11-34
« on: April 21, 2014, 12:05:30 pm »
Sorry for the odd grade measure (yet Wikipedia puts Angle first in Nomenclature ).
Anyhow, it sparked off several interesting topical memories.

Gear Talk / Re: 11-32 vs 11-34
« on: April 21, 2014, 08:54:36 am »
Slopes of  8 degrees is about the maximum you will see on the TransAm.
I think you'll find a lot of people who would dispute that.

John, there are probably few people who are more knowledgeable about the TransAm route than you, so I reverently give way. Still I tried to remember where those wickedly steep slopes occurred. Maybe in Kentucky, where the adrenalin from the many dogs in ambush drove me over the hills?

Did your remark take into account that I mentioned a slope of 8 degrees? More often slopes are expressed as the ratio of rise over run, which for an angle of 8 degrees amounts to a grade of 14%?

Gear Talk / Re: 11-32 vs 11-34
« on: April 18, 2014, 03:11:09 pm »
If you have to ask this question, the best advice is: take 11-34.
As others have said, the difference between 32 and 34 is about half a gear change or -6% in speed at the same cadence. This doesn't sound much, but feels big in the lowest gear.

If you ride at 20 mph, the kinetic energy of your bike and body is about a factor of 20 higher than the energy input from one pedal rotation. If you stop pedalling for a moment the kinetic energy keeps you moving, speed drops slowly and as air resistance drops with the third power of speed, the speed drop is much less than linear with time.
But if you ride uphill with 3 mph, kinetic energy is only about half the energy input from each stroke and gravity weighs linear with speed (at constant gradient). Each pedal stroke has a sense of urgency and speed gets a sawtooth profile because the energy input is only substantial when the crank arms are near horizontal. This 'do-or-die' pounding of the pedals doesn't feel comfortable and doesn't look great.  The more rotations per minute, the smoother and more efficient the pedalling and the less the strain on body (knees) and mind. 

So why doesn't everybody opt for 34t? Well, there is a small weight penalty and the greater efficiency with faster pedalling stops at about 80 rpm. With a 22/32 combination and a 700-32c tires, at 80 rpm you advance about 2.0 m/sec (4.5 mph). At a gradient of 8 degrees, the altitude gain is 0.28 m/sec, which for a weight of 80 kg for rider+bike takes 220W (proportionally more if you are heavier or carrying an additional load). There are not many recreational cyclists around who can produce 220W power in steady-state, say over 20 minutes. Many will reach their limit at 175W steady power output. But those who can produce more power, are lighter or cycle lesser gradients, don't need 34t.

Slopes of  8 degrees is about the maximum you will see on the TransAm. Not in the Appalachians, but in the Ozarks. The Rockies and the Cascades are also less steep.

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