At midnight on Monday I met with two international road race course measurers at East Ferry Road on the Isle of Dogs to measure the London Marathon route for this Sunday's race. Hugh, in his mid fifties is a former London Marathon winner and still very slim and fit looking. Dave who administers course measurement in Asia and Oceana is tough tanned Aussie, also mid fifties I would guess.
I had chosen and purchased my 3 gear Agattu precisely to be able to stay with these two fit bike riders while measuring the London Marathon as well for measuring other races that come my way. Especially the hilly ones and those involving more than 15 to 20 miles riding in a day which is about my limit.
To measure we fix a simple geared revolution counter to the front wheel hub, and calibrate the bike's front wheel in terms of counts per km by riding over a straight calibration course between two nails exactly measured with a long and accurate steel tape measure. We can get well within 0.1% accuracy, that is 42 metres over the marathon distance of 26.2 miles.
We had to ride the shortest possible running line. Imagine a string pulled taut along the whole course - as far as possible in straight runs, and on bends held one foot from the kerb. That is the shortest route which we had to follow from side to side of the road or carriageway as the road curves and goes round corners. We had protection from a van and a pickup from road marking company, usually behind us when we were on the "correct" side of the road, but when the shortest line took us onto the "wrong" side, the van with its yellow lights flashing moved ahead to block off any oncoming traffic. I was surprised how much traffic some of the major roads had between midnight and 4.40 am when we completed measuring the route in 6 segments finishing at the end of Westminster bridge under Big Ben.
We then calibrated again on Rotten Row in Hyde Park, Here is a snap of my two colleagues, standing behind my Agattu which was in pride of place, and admired by them as a good solid bike for measuring.
From my username you may guess that measuring needs 10mph riding for good accuracy, and that is what I based my bike choice on. Unlike some others around this forum who would be impatient at such low speeds, I can concentrate on steady smooth slow riding with minimum wobbles which would add to the distance travelled by the front wheel, and also exact positioning on the corners, 30 cm from the kerb.
However from the start I found that Hugh and Dave on their fast, light racing style bikes could not hold themselves back, and I struggled to keep up as they shot up to 15 mph and even more, and my 23kg pedalec loaded with a pannier bag with 3.5 kg of equipment cut out its assistance as per the electric bike regulations. It left me providing all the power. I was grateful that all the riding I had done over the past 4 months in preparation for my new bike and this occasion came to my rescue, I did not drift more than 40 metres off the back, and of course when there was any sort of slight uphill and they slowed and my bike's power assist came into its own. I kept on level 2 assist since I did not want to risk exhausting the battery on max assist.
The value of the bike's power was also very noticeable when pulling away from a stop. We stopped about 70 times to take intermediate readings, and each time I hardly had to work to accelerate rapidly while I could see Dave immediately in front of me was working hard on his bike to catch up with Hugh at the front. Also it was not long before I decided to mark Dave quite closely and partly shelter my very upright riding position behind his bulk.
If I had known beforehand that my fellow riders would be going over 15 mph I think I would have investigated some illegal change of gearing sprockets to give me a higher cut out speed and reduce the cadence.
The great thing was that I did not really tire too much and towards the end I was keeping up comfortably - they probably slowed a bit but speeds of 15 mph were still common on my GPS.
The other great thing was that the 18Ah battery easily lasted. In all I did 36 miles, all in medium assist, and the last battery LED was glowing steadily - not flashing. I think I used a little more than 80% of the battery capacity. All the stop-start was a good test of hard riding with lots of traffic lights on city streets. I have no doubt one could reliably get over 40 miles for a hard town commute at my weight of 95kg. Riding more leisurely at 10mph at home I had previously got a range 84 miles to battery cut out.
Oh, and the most important thing -- our measurements all agreed with one another within 14 metres. So I think this ride validates the accuracy of electric bikes for use by OAP course measurers, to extend duration of their measuring career.
I now have a measurement ride of the 2012 Olympic Marathon course lined up for late May.
Finally thanks to those forum members who have given me advice over the last 3 months, and gave me confidence to select the Agattu.
I had chosen and purchased my 3 gear Agattu precisely to be able to stay with these two fit bike riders while measuring the London Marathon as well for measuring other races that come my way. Especially the hilly ones and those involving more than 15 to 20 miles riding in a day which is about my limit.
To measure we fix a simple geared revolution counter to the front wheel hub, and calibrate the bike's front wheel in terms of counts per km by riding over a straight calibration course between two nails exactly measured with a long and accurate steel tape measure. We can get well within 0.1% accuracy, that is 42 metres over the marathon distance of 26.2 miles.
We had to ride the shortest possible running line. Imagine a string pulled taut along the whole course - as far as possible in straight runs, and on bends held one foot from the kerb. That is the shortest route which we had to follow from side to side of the road or carriageway as the road curves and goes round corners. We had protection from a van and a pickup from road marking company, usually behind us when we were on the "correct" side of the road, but when the shortest line took us onto the "wrong" side, the van with its yellow lights flashing moved ahead to block off any oncoming traffic. I was surprised how much traffic some of the major roads had between midnight and 4.40 am when we completed measuring the route in 6 segments finishing at the end of Westminster bridge under Big Ben.
We then calibrated again on Rotten Row in Hyde Park, Here is a snap of my two colleagues, standing behind my Agattu which was in pride of place, and admired by them as a good solid bike for measuring.
From my username you may guess that measuring needs 10mph riding for good accuracy, and that is what I based my bike choice on. Unlike some others around this forum who would be impatient at such low speeds, I can concentrate on steady smooth slow riding with minimum wobbles which would add to the distance travelled by the front wheel, and also exact positioning on the corners, 30 cm from the kerb.
However from the start I found that Hugh and Dave on their fast, light racing style bikes could not hold themselves back, and I struggled to keep up as they shot up to 15 mph and even more, and my 23kg pedalec loaded with a pannier bag with 3.5 kg of equipment cut out its assistance as per the electric bike regulations. It left me providing all the power. I was grateful that all the riding I had done over the past 4 months in preparation for my new bike and this occasion came to my rescue, I did not drift more than 40 metres off the back, and of course when there was any sort of slight uphill and they slowed and my bike's power assist came into its own. I kept on level 2 assist since I did not want to risk exhausting the battery on max assist.
The value of the bike's power was also very noticeable when pulling away from a stop. We stopped about 70 times to take intermediate readings, and each time I hardly had to work to accelerate rapidly while I could see Dave immediately in front of me was working hard on his bike to catch up with Hugh at the front. Also it was not long before I decided to mark Dave quite closely and partly shelter my very upright riding position behind his bulk.
If I had known beforehand that my fellow riders would be going over 15 mph I think I would have investigated some illegal change of gearing sprockets to give me a higher cut out speed and reduce the cadence.
The great thing was that I did not really tire too much and towards the end I was keeping up comfortably - they probably slowed a bit but speeds of 15 mph were still common on my GPS.
The other great thing was that the 18Ah battery easily lasted. In all I did 36 miles, all in medium assist, and the last battery LED was glowing steadily - not flashing. I think I used a little more than 80% of the battery capacity. All the stop-start was a good test of hard riding with lots of traffic lights on city streets. I have no doubt one could reliably get over 40 miles for a hard town commute at my weight of 95kg. Riding more leisurely at 10mph at home I had previously got a range 84 miles to battery cut out.
Oh, and the most important thing -- our measurements all agreed with one another within 14 metres. So I think this ride validates the accuracy of electric bikes for use by OAP course measurers, to extend duration of their measuring career.
I now have a measurement ride of the 2012 Olympic Marathon course lined up for late May.
Finally thanks to those forum members who have given me advice over the last 3 months, and gave me confidence to select the Agattu.
