Cen

I couldn't find a table that showed everything I wanted to see regarding gearing.

Playing around in a spreadsheet I came up with this ( https://drive.google.com/open?id=10G...dY5_IotakH5HGE )

Download it in xlsx to modify the values in the yellow cells


The tables show the relation between:

• Wheel and tire size
• Chainring size
• Cog size
• Gear Inches
• RMP's
• Speed (in km/h or mph)
• f200 times

All in one single page!

What I like about it is that after selecting the wheel and tire size you can print a cheat sheet to take to the track!

You can hide gears you don't have and RPM's out of your range to have a more compact table



Do you find these tables useful/easy to use?
Is the lower f200 table accurate based on your personal data?
For example if you know the gearing and cadence you had when you rode your PB you could compare the time.

Comments, critiques, and improvements are accepted!!!

9-2018 Edit: updated link

gtrob

I like it! I usually do a very trial and error method of plugging gears and speeds into a calculator(s), this is very helpful.

So often people throw out gear inch recommendations like they are specific to the track in question, but really they are RIDER specific. What speed do you plan to do, and what cadence do you want to do it at is the real question to determine gear.


Now I just have to figure out HOW to push a 98 gear at 130rpm

Cen

Orrr try pushing:
95" gear at 135rpm
91" gear at 140rpm
for the same results

This is what I like the most, that you can easily see equivalent Gear-RPM combinations on the tables and adjust to your riding stile (strength vs cadence).

Also: You can read the table vertically from the gear, horizontally from the rpm's, diagonally from the speed/time, upwards to get a cog/chainring combo... a lot of info here.

carleton

Nice work, Cen.

Are you differentiating between Actual Gear-inches and Nominal Gear-inches? Most of us use the Nominal 27"*Chainring/Cog. So, 27*50t/15 = "90 gear inches". In actuality it's different, but that's what most trackies in the US use when they are doing calculations.

Also:

- Tire size is negligible being that none of us can hold a perfect line.
- It also should be noted that one would have to average the specified RPM and run the entire event on the black line to get the desired result.

Cen

They are true gear inches (tire outer dia*chainring/cog)
These gear inches will populate the speed table with accurate values. Assuming that your weight will not deform the circunference that much (pump it to the max!

I will incorporate nominal gears in the table! Wait for a revision after I get home tonight.

True. The true gear inches change very little with different tires, but it gives a more accurate speed value for your personal set up.

I know it depends on the track, but what would be ab average distance on a 200 segment stickig to the red line? We can come up with a efficiency factor

About holding or averaging RPM, what is your personal experience? Can you hold max RPM for 11 seconds?

carleton

I can't recall what the difference is, but we do travel more than 200M when we are inside the timed area.

There are a lot of factors, the most significant being the turns. When we are off the measurement line in the turns, we travel a longer distance than when we are similarly off the measurement line on the straights.

Some tracks have 1 turn during a F200M (300M and longer tracks) and others have 2 turns (250M or smaller tracks). Some tracks have short turns and long straights (DLV) and others have long turns and short straights (TTown/COS). So, there's that.

I once did lots of math and realized that, on tracks where the flying 200M has only 1 turn, there is a direct and calculable relationship between max speed and flying 200M time that was accurate to 0.1". So, basically, if you knew your max speed, you could plug it into this formula and get your estimated F200M time. It sounds crazy, but it worked. I compared using data from multiple riders. This was just as accurate as the common practice of timing a Flying 100M and doubling the split and adding 0.1" to estimate what the 200M time would have been.

Coaches will have athletes do flying 100s in practice to test gears, freshness, etc... without totally wiping the athlete out. You can do a lot of testing with flying 100s. More than double the efforts than if you were doing full-on flying 200s.


Max RPM on the track isn't the same as on the road. Being that when we are in the turns and we lean up to 45 degrees to the inside, the centrepital force has our wheels moving faster than our center of mass. So, you'll always see a rise in speed in the turns and a dip when you exit. So, the plot of your speed is wavy. Like this:

Blue: Cadence
Purple: Speed
Green: Power
Red: Heart rate

(Notice the vertical lines on the right that section off the timed 200M. The averages for that split are in the upper left of the split).


So, it may feel like you are holding a constant speed, but we are not.

Cen

Your data is perfect, Carleton, and gave me a lot of ideas for the file!

You can see the modifications using the same links.


Gear Combinations vs Gear Inches Table:

• I added the nominal inches, as suggested.
• As the tire size reduces, the difference between nominal and actual increases.
• If you use a 30mm tire: Nominal=Actual

This table is only modified by "Tire" and "Rim".

Speed Table:

• I changed the name to "Instantaneous Speed"
• This is accurate regardless of the line you choose

This table is not really modified, because the relation between RPM vs Actual Gear Inches is a constant, just choose km/h or mph

Time Table:

• I changed the RPM column to "Average RPM"
• If only the Avg Speed is known, get Avg RPM using the speed table above
• I added a efficiency factor. 100% means you ride the black line all the time, or you ride in a straight line. Find the % that works for you based on known data.

This table is modified by the "Efficiency", the times for each gear inch/rpm combination will increase as the efficiency decreases.
Edit: Changed the efficiency for distance from tires to the black line. Red line at 90cm, perfect line at 0cm.


Example using your 200m data, Carleton

Time:12s
Avg cadence: 138.1rpm = Avg speed 37.56mph

Using the file I would guess you were riding:
90 Actual gear inches (100% efficiency)
98 Actual gear inches (90% efficiency)

What tire/chainring/cog combination were you using?

carleton

That file is one from Giovanni Rey (former track pro). Here is his original blog post: Free Rolling: lines and numbers

A few things to note:

- I only offer the file as an example of how speed fluctuates greatly in what appears to be (and feels like) a gradual wind-up and execution.
- His SRM head unit only sampled every 0.5". So the margin of error when selecting the timed part is 0.5" for the start (0 Meters) and 0.5" on the end (200 Meters) for a total of 1". 1" margin of error during a 4K effort isn't a big deal. It *is* a big deal in a flying 200M. If you use the software you'll see that the vertical lines jump every 0.5". I cannot select, let's say, an 11.7" interval. It's .5s, 1s, 1.5s, 2s, 2.5s...etc...
- Coaches (and myself) often section off 12" of a flying 200M and look at averages. I use the same measure of 12" to stay consistent. If I sectioned off 11.5", the averages would change. So, it's a way to stay consistent during retrospectives, even if I rode an 11.5" during that effort.
- Based on what I can estimate from the chart: At 8 seconds into his flying 200M he was spinning at around 141RPM and traveling at 38.3MPH. Assuming that he rode a 23c tire, that would put him on a 48t/14t, which was a normal elite flying 200M gear back in 2009.

EDIT:

Gio averaged 37.56MPH in this file, that would put his time around 11.9" or 12.0" assuming he rode a good line. This also triangulates with the average cadence being 138RPM, assuming that he rode the 48/14 that I calculated above.

Cen

I really like that strategy! it gives you a reference to compare.
And the average values are something you can trust in a flying 200, unlike the total 200m time due to the 1" margin of error that you explained.


Update on the tables (Links to the files are in the first post of this thread):

• Now you can select your distance from the pole line to get your actual riding distance in a flying 200m
• Read the actual distance in the header of the blue table.
• The times for each gear/rpm combination in the table increase as your distance from the pole line increases.

The formula i came up with to get the additional distance ridden around the track per lap is:

Δ = Actual Distance - Optimum Distance = (pi)2r(cosθ)

Where
pi = 3.1416
r = distance from the tires to the pole line
θ = banking angle in degrees

Selecting a 250m track multiplies Δ times 0.75 (3 out of 4 90ş turns for a flying 200m)
Selecting a 333m track multiplies Δ times 0.5 (2 out of 4 90ş turns for a flying 200m)

I know the angle is not constant, but in the curved segments it doesn't change too much.
And straight segments are negligible (only slight up and down that add to the distance as you go further up the track)
Riding at a certain distance from the pole line in a 0ş velodrome will be longer around the track than riding that same separation in a 45ş velodrome.

I hope you all find modelling this as fun as I do
Now we have a gearing table, speed table, and distance/time table.
Use them together or individually!
Let me know if you need help creating a custom one like mine, I can help you all out (Send me a PM).

carleton

Nice work! Do you record your workouts with a computer that allows for downloading and review of the data?

Now that we've identified what we need to do, the hard part is to get faster

Wind resistance is my biggest problem. I can make more power than most people, but I'm as aero as a tank.

Cen

Thanks, Carleton!
I don't. I am just getting started on this, I'm a former track&field sprinter. I am probably miles and hundreds of laps away from needing to review my data to improve my times. But I would love to have one.

I have a Cateye Strada Cadence, which haven't installed yet.
The only thing that I can measure with it in a sprint is the max speed, everything else would be averaged down with the windup and slowdown.


Like this? hahah

carleton

Hahaha.

Consider saving up for a Garmin Edge 500 or similar (I'm not abreast of the current market offerings). The Garmin Edge 500 records at an interval of 1 reading per second. To get faster readings than that, you'll need an SRM head unit.

I've even tried using Wahoo Fitness app for iPhone, but it didn't work as well as expected. It records at high rates...then normalizes the data back down to 1 reading per second.

Cen

Why would they do that?? Well, I hope by the time I'm ready to get one there will be more options out there. Thanks for the advise!

carleton

Because they think no one needs data with such frequency. It's a simple firmware tweak to implement.

I believe that the head unit will record 4x/second. I imagine that they take so many readings so as not to miss any...but they figure we only want averages and not instantaneous data anyway. It's geared towards everyone but track sprinters.

Cen

The storage capacity will also decrease to 1/4, so no good for roadies.
They should have a toggle option form 1x second to 4x second.
Let's write them a honest customer request hahah they might listen.

carleton

The storage isn't a problem. The device is an iPhone or iPod. Those have gigabytes of storage space. I was using an iPhone4 for my testing.

I've traded several emails with one of the developers. No dice. I even made a suggestion for a product improvement. He said it was a good idea and that even one of the other developers implemented it on his personal experimental setup...still not gonna become a real product

Their target market is tri-geeks who spend loads of cash on equipment thinking it will make them faster. You'd be amazed at how much those folks spend...on anything.

Kaben

Sorry to resurrect such an old thread, but does anyone have a link to this file? Looks perfect for some personal research i'm doing but the files are no longer on the dropbox links provided.

thanks

carleton

My iPhone app does this now in the "TT Simulator" function. The paid app not the free one.

Since I'm not an advertiser, it's not appropriate for me to post links to my paid products/apps.

Morelock

^
iPhone? or Smart Phone?

carleton

Morelock

but Android

carleton

I got 99 programming languages...and Java ain't one.


Sorry.

Morelock

Forgiven

...This time

It'll give me a reason to buy an old iPad sometime.

SyntaxMonstr

Carleton's apps are legitimately the only reason I keep my old iPhone in my track bag.

taras0000

Sadly, I'll never get to use Carleton's app because I refuse to buy Apple products anymore. Looks like it's the slide rule for me!