acceleration

rickt

Any acceleration figures will vary according to gearing used, so to make comparisons, everyone needs to do the EXACT same test. It should also be noted that to get off the mark from a dead stop will be MUCH slower than from a slow moving start. Starting the bike moving in the first place is the most difficult part of the exercise. So to get a good, accurate test result you need to do the test from a dead stop and on a specific gear ratio. As a coach I have a test regime that I have used. On a track bike with 50 x 16 gearing and a timed 100m standing start. Using a hand watch, the quickest I have seen so far was 9.7sec. This was done on Warragul Velodrome.

velomanct

we did some street sprints today, 100meter standing starts. we were on road bikes though, and I started in my 53x21 then shifted. time was 8 seconds, but the distance was not exactly verified. top speed was 34mph though. the pavement wasn't the best either.

__________________
"friendship, family, religion. These are the three demons you must slay if you wish to succeed in business!" -Mr. Burns
The faster you go, the fewer passing cars

velomanct

I was playing around in my street today, did some starts from my mailbox to a telephone poll, which was 8 meters. Got to 26 km/h using my granny gear (39x23) and 21 km/h in a track sprint gear (53x16). I'm going to measure out some longer distances, it's fun being able to test right in front of my house.

__________________
"friendship, family, religion. These are the three demons you must slay if you wish to succeed in business!" -Mr. Burns
The faster you go, the fewer passing cars

WarrenG

For the team sprint you may want to see how quickly (in distance or time) you can get to 37+mph (~36mph for non-aero wheels) in one gear. With your ability I think you'll end up preferring a 53x15.

velomanct

yeh, I'm going to practice a lot of standing starts. and you're right about the gear, I am better off with a slightly larger one. I'm just looking at a ride from last year, did 0-36mph in a 53x15 in 13 seconds. Thing is, I didn't even get above 37 during that 250meter effort. poor top end.

__________________
"friendship, family, religion. These are the three demons you must slay if you wish to succeed in business!" -Mr. Burns
The faster you go, the fewer passing cars

WarrenG

Strength like you have gets you off the line fast but you need good technique to go 37+ in that same gear. Lots of 10-15" sprints out of the saddle that get to around 130+ rpm's will help (53x18?). I do these and focus on sitting down smoothly and continuing to accelerate after I sit down. Important for match sprints too.

Once you're at high rpm's you don't get a great mechanical advantage by being out of the saddle and you're much more aero in the saddle. However, in team sprint you are also trying to help your two teammates behind you so you might want to stay out of the saddle just a bit longer to maintain that great draft for them so it will be easier for them to continue accelerating.

rickt

Try the same 100m test starting on a 53/17 and leave it there, that is almost exactly the same ratio as 50/16, Remember that the initial start is the most difficult part of the excercise, so reducing the start gear allows for completely different acceleration. In fact the 50/16 combo is 23.5% higher than 53/21. The 9.7 was also done on 165mm cranks which produce approx 3% less leverage than 170mm cranks, and are therefore harder to get going from stopped.