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[quote=henk4;929006]Interesting figures...
Questions:
What gear ratio did you use? Front blade and rear please.
Did you shift and if so to what gears?
and btw 10-speed is purely theoretical, there will certainly be overlaps, and using the large front blade in combo with the largest sprocket on the wheel will wear out your chain very rapidly.[/quote]
That is a tough question, having done the test so many years ago.
I know I started out in 1st gear. IIRC, I did "jump" a gear or two because it would have hurt the acceleration times if I shifted one gear at a time. It was probably something like 1st to 3rd to 7th to 9th.
I always did like to keep the chain on the smaller of the two on the front sprocket.
I did forget to mention that my bicycle had a speedometer. For the mph acceleration, I called out when I reached a certain speed and my brother would tell me the time on the watch.
[quote]When the weather gets a bit better here I'll see what I can do with my 30-speed gearbox....[/quote]
It would be interesting to see the results.
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As you may know, the standing kilometer is an official part of indoor track biking. Here they use a bike without any gears at all. It takes some time to get going, but apparently that compensates for the time lost during gear shifting even with the most advanced electronically assisted shifters.
Furthermore, the times achievable depend much more on the power of the rider than on anything else:)
EDIT: using 1 and 3 gear and 7th and 9th, implies a change of the front sprocket, in 1974 there was no possibility to use a ten ten sprocket freewheel.
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I also did do some acceleration runs with my single-speed early-'70s dirt bike. It was not all one make; it was a Schwinn frame with parts I added on- rims, saddle, handlebars, etc.
As you said, being one speed, there was no time wasted shifting, but it did take longer to accelerate off the line.
I used to know the gears in each sprocket. I think it was 1, 3, 5, 7 and 9 for the smaller front one and 2, 4, 6, 8 and 10 for the bigger one. My older brother may remember since he also owned several 10- and 12-speed bikes.
I do remember that the gear changes did not go 1-2-3-4-5 with one sprocket like many people thought back then.
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[quote=Fleet 500;929040]I also did do some acceleration runs with my single-speed early-'70s dirt bike. It was not all one make; it was a Schwinn frame with parts I added on- rims, saddle, handlebars, etc.
As you said, being one speed, there was no time wasted shifting, but it did take longer to accelerate off the line.
I used to know the gears in each sprocket. I think it was 1, 3, 5, 7 and 9 for the smaller front one and 2, 4, 6, 8 and 10 for the bigger one. My older brother may remember since he also owned several 10- and 12-speed bikes.
I do remember that the gear changes did not go 1-2-3-4-5 with one sprocket like many people thought back then.[/quote]
With two front sprockets and five at the freewheel, you will generally use the smaller front sprocket with the three largest sprockets on the freewheeel and the larger front one with the smallest three. (effectively giving you 6 speeds, without overlap). My front sprockets are 53/42/30 and the rears are 12/13/14/15/16/17/19/21/23....I will never use 53/23 as a drive.....normal driving at about 20-22 mph is with 42/15 or 42/14, and when I have a tailwind I shift to the 53, but then with the 17/16/15. Thinking about how to do a quarter mile, I might use 42/15 all the way or perhaps shift up to 53/15 towards the end. (I have a new 46 front sprocket available which I will use on the flats, just to reduce the difference between the two larger front sprockets, to give a smoother gear change, with far less big gaps.
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[quote=henk4;929049]With two front sprockets and five at the freewheel, you will generally use the smaller front sprocket with the three largest sprockets on the freewheeel and the larger front one with the smallest three. (effectively giving you 6 speeds, without overlap). My front sprockets are 53/42/30 and the rears are 12/13/14/15/16/17/19/21/23....I will never use 53/23 as a drive.....normal driving at about 20-22 mph is with 42/15 or 42/14, and when I have a tailwind I shift to the 53, but then with the 17/16/15. Thinking about how to do a quarter mile, I might use 42/15 all the way or perhaps shift up to 53/15 towards the end. (I have a new 46 front sprocket available which I will use on the flats, just to reduce the difference between the two larger front sprockets, to give a smoother gear change, with far less big gaps.[/quote]
How many times would you shift, then, throughout the 1/4 mile run?
20-22 mph is good cruising speed for a bike. With the bike I ride most, a reproduction of a '70s Schwinn Stingray, my cruising speed on level ground is usually about 14-15 mph. I also have a mountain bike (Diamondback Response) and I can cruise a little faster with that, maybe 18 mph.
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[quote=Fleet 500;929052]How many times would you shift, then, throughout the 1/4 mile run?
20-22 mph is good cruising speed for a bike. With the bike I ride most, a reproduction of a '70s Schwinn Stingray, my cruising speed on level ground is usually about 14-15 mph. I also have a mountain bike (Diamondback Response) and I can cruise a little faster with that, maybe 18 mph.[/quote]
once, going from 42 to 53.
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[quote=henk4;929062]once, going from 42 to 53.[/quote]
That should provide good acceleration times, then. Less time lost in shifting.
And what you said is true... much or most of it depends on the rider.
You won't see some overweight, out-of-shape 70-year-old doing a 33-second 1/4 mile!
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[quote=Fleet 500;929071]That should provide good acceleration times, then. Less time lost in shifting.
And what you said is true... much or most of it depends on the rider.
You won't see some overweight, out-of-shape 70-year-old doing a 33-second 1/4 mile![/quote]
I am 61 and slightly overweight....first have to find a flat 402 meter stretch where I can go all-out (and no wind influence, which is quite difficult....)
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Flat shouldn't be a problem in NL, but no wind is quite another issue...
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[quote=henk4;929072]I am 61 and slightly overweight....first have to find a flat 402 meter stretch where I can go all-out (and no wind influence, which is quite difficult....)[/quote]
Too bad you didn't do the test at the age I did mine (about 16 years old).
Yes, definitely make sure it's a flat surface and on a calm day, weather-wise.
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As I know 17yo girls who can cover cover 500m on the velodrome in 37 seconds you needed to get a bit fitter back then, Fleet. Olympic standard for the girls standing 500m is around the 34s mark. I expect it to be under that in London. The guys go through the 500 in about 32s, on their way to 1km. World record in the standing 1km is now under 1 min.
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[quote=Cyco;929108]As I know 17yo girls who can cover cover 500m on the velodrome in 37 seconds you needed to get a bit fitter back then, Fleet. Olympic standard for the girls standing 500m is around the 34s mark. I expect it to be under that in London. The guys go through the 500 in about 32s, on their way to 1km. World record in the standing 1km is now under 1 min.[/quote]
Well, I do remember that I did the one mile run in 7 min and 31 sec., which was ahead of some other students. That was in high school.
In Jr. High, I could run the 100 yard dash (that was the distance they used back then) in 12.9 seconds.
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1 Attachment(s)
I found the figures for my other bike.
This one is (I still have it) a "dirt bike" from about 1974. A Schwinn frame and I put it together using other components (rims, seat, tires, handlebars). See photo.
A single-speed bicycle with a coaster brake. Front tire 20"x1.75" and rear tire 20"x2.25".
Here are the figures I got back in the mid-to-late '70s:
0-10 mph-------------- 3.2 seconds
0-15 mph-------------- 4.2
0-20 mph-------------- 6.5
0-25 mph-------------- 10.0
Passing: 5-15 mph------ 4.3 secs.
--------10-20 mph------ 5.2
Top speed-------------- 27-28 mph on level ground
No 1/4 mile time, but I did do a 400 foot run... 14.2 seconds.
The 10-speed bike, of course, was faster off the line. The single-speed bike took a few seconds to gather some speed, but did well in the mid-range (10-20 mph).
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[quote=Fleet 500;928906]I once raced a moped from a standing start. I easily won but it was one of the slower mopeds.[/quote]
I started out behind a moped which was already moving at full throttle and passed it on my 3 speed bicycle. Of course, I was much younger then.