Hey Everyone,

Quick question about estimating speed on a cycle. Swimming and cycling there is a lot of resources but I can't find cycling.

If you want to do a 2:40 90km cycle as part of a 70.3. I have assumed you need to do a 2:25 by itself (feel free to stand corrected)

so what would the estimate or conversion to the following be?

40km
20km
10km

You can get a heads-up on this from our pacing calculator, enter your event time/distance (eg 90km) and it should work out what you need in terms of power / speed (and optionally corrects for need to run after the cycle leg) see bit.ly/fftbonk. regards from FFT
FastFitnessTips wrote:
You can get a heads-up on this from our pacing calculator, enter your event time/distance (eg 90km) and it should work out what you need in terms of power / speed (and optionally corrects for need to run after the cycle leg) see bit.ly/fftbonk. regards from FFT

Sorry to be a pain. Where is "our" pacing calculator :-)
I typically ride under 2:30 (2:24-2:28 if flat) in a HIM, in a 40k during an Oly dist race I'll ride just over an hour (1:01ish if flat) and in a 20k during a sprint dist race I'll ride under 30 min.
jaretj wrote:
I typically ride under 2:30 (2:24-2:28 if flat) in a HIM, in a 40k during an Oly dist race I'll ride just over an hour (1:01ish if flat) and in a 20k during a sprint dist race I'll ride under 30 min.

Wow fook ok.

So 35kph is like 38kph in 40k and 40kph for 20mins.

Fook. Ok.

Thanks thou!
Hey Everyone,

Quick question about estimating speed on a cycle. Swimming and cycling there is a lot of resources but I can't find cycling.

If you want to do a 2:40 90km cycle as part of a 70.3. I have assumed you need to do a 2:25 by itself (feel free to stand corrected)

so what would the estimate or conversion to the following be?

40km
20km
10km

Use Best Bike Split.
I really don't think it's useful to try and extrapolate estimates like this.
It's not just a case of comparing short to long distances (which isn't a fixed relationship and depends heavily on the athletes endurance). Even comparing one 70.3 to another 70.3 you could have wildly diferrent times for the same athlete in the same condition. Route and weather make a massive difference. I've done flat courses with ~200m of total altitude gain and no technical corners in flat calm conditions, and I've done courses with over 1000m of altitude gain in wind and rain with technical sections. They're not comparable.

My advice would be to take a look at bestbikesplit.com.
Import some routes you've already cycled recently at a hard effort. Input your details and those of your bike and position. Use your best guess at the wind when you rode the route and see how much power bestbikesplit thinks was required for the time it took you. You may not have distributed your effort quite the same as BBS suggests but it should still be a reasonable estimate. Now use that number as a baseline and model the route you're interested in for the conditions you expect (or hope for ;)). You can tweak the power up or down a bit depending on the duration being longer or shorter and factoring in triathlon versus stand alone cycle.

Longer hard, consistent rides will give you a far better baseline for long race rides. Not much point considering a 10km stand alone TT for comparison to a 90km bike leg in a triathlon, even without taking route and coditions into account this is too variable to be useful.

You should have a much better estimate of what you can do from your training rides than you'll get from most mathematical models or rules of thumb. I've found BBS useful in the past for making pretty accurate forecasts but only because I have a clear idea of the power I can produce for a given amount of time, have run enough models to reasonably refine my aerodynamic parameters, and because I'm confining my estimate to a specific routes and anticipated weather conditions.

Sorry if this is a long read!
The short version is there is no short version - that gives a useful answer.
Ai_1 wrote:
I really don't think it's useful to try and extrapolate estimates like this.
It's not just a case of comparing short to long distances (which isn't a fixed relationship and depends heavily on the athletes endurance). Even comparing one 70.3 to another 70.3 you could have wildly diferrent times for the same athlete in the same condition. Route and weather make a massive difference. I've done flat courses with ~200m of total altitude gain and no technical corners in flat calm conditions, and I've done courses with over 1000m of altitude gain in wind and rain with technical sections. They're not comparable.

My advice would be to take a look at bestbikesplit.com.
Import some routes you've already cycled recently at a hard effort. Input your details and those of your bike and position. Use your best guess at the wind when you rode the route and see how much power bestbikesplit thinks was required for the time it took you. You may not have distributed your effort quite the same as BBS suggests but it should still be a reasonable estimate. Now use that number as a baseline and model the route you're interested in for the conditions you expect (or hope for ;)). You can tweak the power up or down a bit depending on the duration being longer or shorter and factoring in triathlon versus stand alone cycle.

Longer hard, consistent rides will give you a far better baseline for long race rides. Not much point considering a 10km stand alone TT for comparison to a 90km bike leg in a triathlon, even without taking route and coditions into account this is too variable to be useful.

You should have a much better estimate of what you can do from your training rides than you'll get from most mathematical models or rules of thumb. I've found BBS useful in the past for making pretty accurate forecasts but only because I have a clear idea of the power I can produce for a given amount of time, have run enough models to reasonably refine my aerodynamic parameters, and because I'm confining my estimate to a specific routes and anticipated weather conditions.

Sorry if this is a long read!
The short version is there is no short version - that gives a useful answer.

Will take a look at this site. Cheers u two.

I like to break goals down into manageable chunks. Like running if I want 1:30, i should be able to go under 20min 5km first. Im just using the same approach for cycling :-)

I cant go physically faster than 33kph atm. So this is why its good to know
The best predictor of performance is performance itself?

I'd be careful extrapolating down and up too aggressively..........without actually trying it in the wild.

It's not always as simple as "I can ride a 90k at 23mph, so my 40k must be 24mph, my 15k must be 25mph". The 90k to 15k seems to only be 2mph, yeah that 2mph could be up to 40w difference. That's not trivial.

Same the other way, if you're a bike racer who can do a 15k at 27mph don't go thinking you could do a 90k a 25mph.

Try it and see. It hurts, but a 15k is only like 25min. Even a 90k, that's just a 2.5hr ride. So, in a single week you could do both and know for sure.
Those are paces I can go and run effectively afterwards.

The shorter distances are probably skewed faster because it doesn't seem to matter how fast I go, I'll still run the same. For a 40k, if I ride a 1:01 or a 1:05 I'm still going to run about 45 min for the 10k. For 20k I can ride 29 min or 35 min I'm still going to run ~22ish for the 5k.

But for a 70.3, if I ride under 2:25 I'm probably going to run 15 min slower than I'm capable of.
........I like to break goals down into manageable chunks. Like running if I want 1:30, i should be able to go under 20min 5km first. Im just using the same approach for cycling :-)

I cant go physically faster than 33kph atm. So this is why its good to know
Running pace is far less dependent on route and conditions than cycling. I don't think the same approach is anywhere near as useful on the bike.

What do you mean when you say you can't physically go faster than 33km/h ATM? That could mean many things. I'm assuming that's your best average over some specific distance on a closed loop course?
The extra details matter a lot. I could, and have, reached about 90km/h over a couple of km of straight descent. I've cruised easily at 45km/h on flat road with a stiff tailwind and I've averaged ~22km/h while working fairly hard on long, very hilly training rides. I've also averaged ~40km/h for sprint distance triathlon and duathlon. None of these predict each other. And if you asked me what's the highest speed I can physically achieve, I wouldn't know how to answer. I could tell you my estimated FTP?
burnthesheep wrote:
The best predictor of performance is performance itself?...
Yep - Have to agree with Coggan on that one!
Ai_1 wrote:
burnthesheep wrote:
The best predictor of performance is performance itself?...

Yep - Have to agree with Coggan on that one!

It took me taking some lumps in some events to start to "get it".

I'm still a relative freshman to bike racing and anything multisport, but the little soundbite is starting to make sense.

I've been "that guy" that would look at my optimal indoor controlled situation 20min tests and do mental gymnastics about what I "could" do in the wild. Hit up the online calculator tool and start thinking.......hey, I should be able to do XYZ.

This led to me taking those lumps and disappointments in races, or events, or whatever.

A recent change in view has been refreshing. Doesn't mean I'll ever "win" a bike race or podium an AG, but I can work more effectively towards results now.
Ai_1 wrote:
........I like to break goals down into manageable chunks. Like running if I want 1:30, i should be able to go under 20min 5km first. Im just using the same approach for cycling :-)

I cant go physically faster than 33kph atm. So this is why its good to know

Running pace is far less dependent on route and conditions than cycling. I don't think the same approach is anywhere near as useful on the bike.

What do you mean when you say you can't physically go faster than 33km/h ATM? That could mean many things. I'm assuming that's your best average over some specific distance on a closed loop course?
The extra details matter a lot. I could, and have, reached about 90km/h over a couple of km of straight descent. I've cruised easily at 45km/h on flat road with a stiff tailwind and I've averaged ~22km/h while working fairly hard on long, very hilly training rides. I've also averaged ~40km/h for sprint distance triathlon and duathlon. None of these predict each other. And if you asked me what's the highest speed I can physically achieve, I wouldn't know how to answer. I could tell you my estimated FTP?

Honestly, I do not know. On a straight, even if I use absolutely all my muscle.... I may be able to get to 35kph for a small while. Realistically I ride at 33kph but I can do that for an hourish. 28kph is my pace that feels like I am using my cardio system as my muscles relax. There just is no down strength (is that how you guys say it)

for instance.. my heart rate never goes over 130 (im 32) when I am cycling. Even at the end of my 4 hour 70.3 cycle last year, I had a heart rate of 130 prior to the run (which went up to 170 4k in)

Bike is something I am currently at a loss on how to improve (other than riding 300km a week... I just started again with 5 hours a week and experiencing the same problem, hence trying to work out how fast you guys go)
That sounds rather odd to me.
Most people have lower max heart rate on the bike, but only by a few beats per minute. If your HR is in the 170bpm region for the run of a 70.3, and for the bike it's only 130bpm, it sounds like you're taking it very easy on the bike, but you say you're not.
For context, my max HR is around 186-188 for both bike and run. I would have a HR in the 155-165 range throughout the ride and maybe 160-165 for the run.

My best guess is you have some bike specific muscle weakness preventing you from using your "engine" on the bike. But I'm only guessing.
Ai_1 wrote:
That sounds rather odd to me.
Most people have lower max heart rate on the bike, but only by a few beats per minute. If your HR is in the 170bpm region for the run of a 70.3, and for the bike it's only 130bpm, it sounds like you're taking it very easy on the bike, but you say you're not.
For context, my max HR is around 186-188 for both bike and run. I would have a HR in the 155-165 range throughout the ride and maybe 160-165 for the run.

My best guess is you have some bike specific muscle weakness preventing you from using your "engine" on the bike. But I'm only guessing.

That is interesting, thank you. I need to figure this out.
It sounds odd to me as well.

My HR on the run when going really hard is 155 to 160 while on the bike I can get up just over 150 when going really hard.
Ai_1 wrote:
I like to break goals down into manageable chunks. Like running if I want 1:30, i should be able to go under 20min 5km first. Im just using the same approach for cycling :-)

I cant go physically faster than 33kph atm. So this is why its good to know

It's not really possible to take that approach in cycling.

( :-) )

Everyone's power curve is different, and sifted significantly by training.
And you don't have to run a sub 20min 5km to run a sub 1.30 half. ;-)
Hey Everyone,

Quick question about estimating speed on a cycle. Swimming and cycling there is a lot of resources but I can't find cycling.

If you want to do a 2:40 90km cycle as part of a 70.3. I have assumed you need to do a 2:25 by itself (feel free to stand corrected)

so what would the estimate or conversion to the following be?

40km
20km
10km

The two main things you would need to understand are

- The power you are able to hold over different period of time
- You coefficient of aerodynamic drag

There are other factors but those are the biggies.

Some people can generate big watts for a short duration and will do really well on a 10km TT. Others can hold power for longer time and will do relatively better on the 70.3 course

Some people have a great CDA that impacts things much more at higher speeds (like in a 10km TT) vs a slower 90km course

That being said you can do some back of the napkin calculations

Let's say your FTP is 240w and your CDA is .3. <pink> Most STers have double that FTP and half that CDA </pink>

A rule of thumb is you could do 105% of that for 20min so 252w. It takes this 252w to go 38.5km/h (assuming crr of .004, air density 1.18 bla bla bla). 15kmTT would be a good test.

If your FTP is 240 you can probably do a 40km TT around that power. It takes that 240w to go 37.8km/h (same bla bla)

If you want to pace a HIM conservatively at 78% of FTP that would be 187 watts, It takes 187watts to go 34.5 km/h which would bring your HIM to 2h36min.

So

38.5 for 15km TT
37.8 for 40km TT
34.5 for 90km HIM

Very rough calculations but with a power meter you can test, refine, model and do some pretty good projections
Last edited by: marcag: May 2, 19 5:02
marcag wrote:
A rule of thumb is you could do 105% of that for 20min so 252w.

Not many.

In "The 33 - Bike Racing" forum, lots of people seem to arrive at more like 90-92%. Anything from moi as a Cat 5 to some of the Cat 2 guys I follow on there.

Going shorter down the ladder in duration from 1/2 distance to 10mi TT, you're likely to see less improvement in someone who doesn't have as much anaerobic focus (true triathlete vs. true bike racer). If you're fast in a 10mi TT, you're relying on more anaerobic capability and can probably rely on it over some roller hills and then recover a touch more than in a longer event.

I think the exception would be single-sport British time triallists who do both the 15k stuff and the 50mi TT stuff (think Obree, anything from World pursuit champion up to British 50mi TT champion).

It's good to set goals..........I'm just saying this stuff because I've been there. I tried to apply math, percentages of power, and lots of mental gymnastics to set goals that were NOT based in reality.

Instead, recently, I got a baseline off of a few real world 15k and 40k rides for my TT goals.

Now, I'm basing my goals off of that real world performance. Actual power and HR data from those rides. How much wind and elevation actually affected the ride.

I can then use online tools to get an idea of a strategy and goals for what I do.

It should go:

real world trial (at desired distance) -> data -> apply a model or calculator to data -> make a plan for a ride from data-> ride -> repeat

It probably isn't as good to:

Zwift ftp test -> apply a model or calculator to data from a different ride -> make a plan for a ride -> ride

Geeez.......a 15k TT is going to be like 40 TSS and 25min of your time. A 40k, probably just at/over an hour. Etc...people spend that much time talking on Slowtwitch.
.....On a straight, even if I use absolutely all my muscle.... I may be able to get to 35kph for a small while. Realistically I ride at 33kph but I can do that for an hourish. 28kph is my pace that feels like I am using my cardio system as my muscles relax.....
When you say using absolutely all your muscle you may reach 35km/h for a short while, what do you mean by a short while?
A true max effort will only last a few seconds. If you can sustain it longer than that it's not a max effort. In terms of power, my max is about 350-360% FTP. I think that's fairly typical although good sprinters might be much higher. And if you can cruise at 33km/h for an hour, there's no way you're limited to 35 by "muscle".

Also, what do you mean about 28km/h with relaxed muscles? You can't do work with a relaxed muscle ;)
I share your experience and summarized it with

"Very rough calculations but with a power meter you can test, refine, model and do some pretty good projections "

BTW, projecting HIM pacing, which is what the OP wants, is even more fun given the impact a swim has and impact on run. But there are ways to do it. Not pefect but pretty helpful.
Incorrectly attributed quote.
You've attributed Bonmaklad's comments to me, and yours to him. I said none of that.
Ai_1 wrote:
Incorrectly attributed quote.
You've attributed Bonmaklad's comments to me, and yours to him. I said none of that.

It really doesn't matter - I got the deleting wrong on the quotation - the reply was to Bonmaklad's original question, that's what matters.