Today I did an experiment to measure just how much additional friction is in a Derailleur as opposed to a single speed setup. An easy test shows that the derailleur has more friction. Take the pedals and spin them backwards in each setup. What you will find is that when connected to a derailleur the pedals stop quickly. In my case in about 1/2 a turn. Whereas in the single speed setup the pedals move easily, in my case more one turn.
I wanted a more quantitative measure of the difference than just the above observation. So I attached a weight to the pedals and measured the amount of weight needed to take the pedals from horizontal to vertical in 1/2 a second. What I found was that the derailleur took 4 times as much weight. This means that the power output needed to just turn the pedals is 4 times more for the derailleur than in the single speed setup.
Next I tried to determine the actual power needed. This was a very crude estimate but I came up with 16 Watts for the derailleur verses 4 Watts for the single speed. The difference of 12 Watts is power that is not going to moving the bike but is needed to just overcome drive train friction.
At the Iola race an additional 12 Watts of power for me would have translated to reducing my race time by two and a half minutes. That would have moved me from fifth to third in my age group.
All these measurements were crude but show that friction is the real enemy and a simple configuration such as a single speed can help lower it by a significant amount.
I want to improve my measurements to get a better estimate of the difference in power so stay tuned.
Mike
Monday, May 16, 2011
Sunday, May 8, 2011
A Recovery Week
This week has been a recovery week. I have had four hard training weeks in April and following the Iola race I was very tired. Also the semester is about to end and that means things are very busy at school, so this was an ideal time for a little rest. Tuesday I did a recovery ride and then again on Thursday with Monday, Wednesday and Friday off.
Saturday I did a very intense one and a half hour tempo/threshold ride on the road. Then today I went to the trails in the Northern Kettles for the first time this year. They are finally open. All the rides this week were with the 1x9 geared setup. My plan is to keep the 1x9 setup on for the coming week to get some baseline PowerTap data and then go back to the single speed setup next weekend. That way I should be able to compare geared to single speed performance under similiar conditioning.
One interesting thing I've noticed is that with the single speed setup The crank will easily spin backwards several times with an gentle push compared to only about a half turn when I have a deraillier setup. This shows that there is more friction in the geared configuration. I want to see if I can figure out a way using the PowerTap to measure just how much additional friction there is with the deraillier. I have an idea how to do this but we will just have to see if it works.
Back to harder training this week.
Mike
Saturday I did a very intense one and a half hour tempo/threshold ride on the road. Then today I went to the trails in the Northern Kettles for the first time this year. They are finally open. All the rides this week were with the 1x9 geared setup. My plan is to keep the 1x9 setup on for the coming week to get some baseline PowerTap data and then go back to the single speed setup next weekend. That way I should be able to compare geared to single speed performance under similiar conditioning.
One interesting thing I've noticed is that with the single speed setup The crank will easily spin backwards several times with an gentle push compared to only about a half turn when I have a deraillier setup. This shows that there is more friction in the geared configuration. I want to see if I can figure out a way using the PowerTap to measure just how much additional friction there is with the deraillier. I have an idea how to do this but we will just have to see if it works.
Back to harder training this week.
Mike
Tuesday, May 3, 2011
The Iola Race
Saturday I drove to Iola to pre-ride the course. I started with a 34x18 gear which was too big. I could not climb any of the four major climbs on the course. So I changed to a 34x19 gear. This made the climbing better but I could only do 1 of 4 climbs. Then I went to a 33x19 combination. This achieved 2 of 4 climbs. By that time I was too tired to try another lap.
Saturday evening, when I was back home, I changed to a 32x19 gear. Then Sunday morning I decided to just put my 1x9 geared setup back on the bike for the race. I felt that I needed some off-road single speed time before trying to race. Single speeding is more than just a bike, there is a definite technique to successful riding.
At the start of the race I was positioned at the front of my wave. The race started very fast and by the first climb I was in the middle of the wave. However, I started passing riders even on the first climb. At Iola you pass through the ski bowl twice each lap. The second pass consist of a fast descent followed by a quick, steep uphill. It is essential to hit the bottom of the hill as fast as you can to make good time to the top. On the first lap I descended at 31 mph. However, when I reached the bottom of the climb the course was filled with walking riders and no way around them. I had to skid to a halt and run my bike up the hill. After that the course was clear for the rest of the race and it was a "go as fast as you can" for the race.
At the end I finished 5th out of 9 in my age group (60+). I was 4 minutes from the winner of the age group. Each lap was faster than the previous lap which is a good sign. It was a good time and it was great to see everyone after a long winter. The one sad note was that the fastest rider in the 60+ age group, Wayne Fish, passed away over the winter. Wayne was a real competitor. I never beat him but always looked forward to trying to close the time gap each race. Wayne will be missed.
As to the single speed, I plan to get some off-road training rides in now that the trails are open and hopefully be really to try a race on the single speed next time.
Mike
Saturday evening, when I was back home, I changed to a 32x19 gear. Then Sunday morning I decided to just put my 1x9 geared setup back on the bike for the race. I felt that I needed some off-road single speed time before trying to race. Single speeding is more than just a bike, there is a definite technique to successful riding.
At the start of the race I was positioned at the front of my wave. The race started very fast and by the first climb I was in the middle of the wave. However, I started passing riders even on the first climb. At Iola you pass through the ski bowl twice each lap. The second pass consist of a fast descent followed by a quick, steep uphill. It is essential to hit the bottom of the hill as fast as you can to make good time to the top. On the first lap I descended at 31 mph. However, when I reached the bottom of the climb the course was filled with walking riders and no way around them. I had to skid to a halt and run my bike up the hill. After that the course was clear for the rest of the race and it was a "go as fast as you can" for the race.
At the end I finished 5th out of 9 in my age group (60+). I was 4 minutes from the winner of the age group. Each lap was faster than the previous lap which is a good sign. It was a good time and it was great to see everyone after a long winter. The one sad note was that the fastest rider in the 60+ age group, Wayne Fish, passed away over the winter. Wayne was a real competitor. I never beat him but always looked forward to trying to close the time gap each race. Wayne will be missed.
As to the single speed, I plan to get some off-road training rides in now that the trails are open and hopefully be really to try a race on the single speed next time.
Mike
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