Login required to started new threads

Login required to post replies

Prev Next
Does optimal pacing matter this much?
Quote | Reply
So I've been playing around with BestBikeSplit.com and comparing the output to my recent race results. Long story short I can't get the predicted value to come very close to my actual race result. Here is a link to the BBS prediction: http://www.bestbikesplit.com/public-race?r=4115 . I've played around a lot with the bike setup and change wind/yaw angles quite a bit without any luck. Here is a link to my power data from Oceanside a few weeks ago: http://tpks.ws/lLrx . It seems like a lot of people have had good success with the site. The prediction around 7 minutes off and I can't seem to get things to go over 2:40. Does correct pacing matter to the point that you can gain 7+ minutes? I'm riding a road bike with clip on aero bars.
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
There will be more vairability in your bike setup. Yes unevern pacing can definitely cost you time.

How much did you use your brakes? Sit up to eat, drink, stretch out?


TrainingBible Coaching
http://www.trainingbible.com
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
It doesn't look to me like your pacing is the real problem. Unless you're really large, you're likely not very aero. 240 watts is a very high power output for 20.1 mph, looks like the course had some climbing but not super hard. I can average 20 mph on AP of 160 watts over rolling terrain with similar elevation gain, and I'm not super lightweight at 160 lbs.

Looks like you're on a road bike w/ clip ons? That doesn't help, but your position is likely the biggest culprit. You should have a lot of room for improvement, though you may have to spend some money.
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
The biggest source of error will be your estimation of what your CdA is and what the wind was doing.

Everything else will be very exact (assuming your power meter and scale work!)

So either the wind was stronger than you are putting in, or your CdA is worse. Rolling resistance possibly too, what tires were you on, at what psi?



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
I tried bestbikesplit and it wasn't even close for IMWI. It did okay on some of the flatter races I've done.
Quote Reply
Re: Does optimal pacing matter this much? [Supersquid] [ In reply to ]
Quote | Reply
Sorry, didn't look at the file closely before. Based on the pro times it's fairly hilly, and the winds took their toll. The killer is having to hit the brakes on the downhill due to the speed limit imposed (lame), hard to factor that in.

All that being said, wind can play a major role, but I'd say mostly it's having trouble modeling your aerodymanics. Unless your really tall/large, That's really slow for that wattage. That's pretty close to my target wattage and I'm expect to average just over 23mph on that course, but it's really hard to say for sure.

I think that's a tough course to model with variable winds on the coast and the hills, turns, etc.

It think it's very clear the your position is probably costing you a lot of time, but that's common on a road bike with aerobars. It takes a lot of major adjustments to get into a good TT position on that type of frame.


TrainingBible Coaching
http://www.trainingbible.com
Quote Reply
Re: Does optimal pacing matter this much? [jackmott] [ In reply to ]
Quote | Reply
I raced at 172 lbs and am 6' tall, so it seems that my aero setup could use a lot of work considering some of the data points given here. There were definitely strong winds coming in at miles 46-56, but this is fairly typical on the course from what I've heard (though not correctly factored into the model). If I go under 5 hours at Vineman 70.3 then I'll spend money on a nice aero setup. It will be an interesting experiment to see how much time I can actually get out of it.

Tires were Conti gp4000s at 120 psi. They were a little worn down, but not too bad.
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
Hey most likely CdA issues, but also it is dependent on the quality of the course input. We have a new feature where we verify courses (painstakingly look over many course data files for elevation consistency as well as mapquest and google elevation profiles). If you look at 5 elevation profiles for a course taken from a 910xt none will be even close to the same (and typically none will be accurate). Since it seems you used the verified Oceanside course we have actually hit almost exact times for multiple pros using their wind tunnel data. If you want me to take a look at your CdA numbers and give a suggestion let me know (or try a different course as well) and see if it's still under reporting by that significant a margin (then it's most like CdA). Also to do a comparison it's probably more accurate to use a number closer to your average power if you have a really big average / NP split.

-----------------------------------------------------------------
Founder: BestBikeSplit
Amazonian
Quote Reply
Re: Does optimal pacing matter this much? [motoguy128] [ In reply to ]
Quote | Reply
We apply a downhill speed limit (and a speed where you may come out of aero to apply brakes) based on athlete experience setting. Somewhat generic but tends to hold pretty true.

-----------------------------------------------------------------
Founder: BestBikeSplit
Amazonian
Quote Reply
Re: Does optimal pacing matter this much? [Supersquid] [ In reply to ]
Quote | Reply
I know IM Wisconsin continues to be a pain for us. I've tried to get good elevation profiles for quite some time. Looking for lots of 800/810 data and comparing it to Google and Mapquest to get a better picture but still not there on that course. We did refine some deceleration / acceleration modeling in the past week so if you haven't run it in a while you can probably try again and see if that helps a bit.

-----------------------------------------------------------------
Founder: BestBikeSplit
Amazonian
Quote Reply
Re: Does optimal pacing matter this much? [Mrcooper] [ In reply to ]
Quote | Reply
Are you sure it's an elevation issue and not the fact that 90% of the roads are total shit?
Quote Reply
Re: Does optimal pacing matter this much? [Mrcooper] [ In reply to ]
Quote | Reply
Mrcooper wrote:
Hey most likely CdA issues, but also it is dependent on the quality of the course input. We have a new feature where we verify courses (painstakingly look over many course data files for elevation consistency as well as mapquest and google elevation profiles). If you look at 5 elevation profiles for a course taken from a 910xt none will be even close to the same (and typically none will be accurate). Since it seems you used the verified Oceanside course we have actually hit almost exact times for multiple pros using their wind tunnel data. If you want me to take a look at your CdA numbers and give a suggestion let me know (or try a different course as well) and see if it's still under reporting by that significant a margin (then it's most like CdA). Also to do a comparison it's probably more accurate to use a number closer to your average power if you have a really big average / NP split.

I'll play around with another race that I have power data for. I guess I could always back in to the "correct" CdA for my current setup based upon the output from the model and my actual race times. Though the pacing strategy wouldn't quite line up, I'd imagine things would be somewhat accurate.

Once I'm on a new bike setup I'll have ERO sports do some aero testing and get some accurate CdA numbers. Should make playing around with BBS and power data even more fun.
Quote Reply
Re: Does optimal pacing matter this much? [Supersquid] [ In reply to ]
Quote | Reply
There is that. For some courses not currently in the system we go through and change road conditions (and wind profile) by segment (that is very painstaking).

-----------------------------------------------------------------
Founder: BestBikeSplit
Amazonian
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
ERO and alphamantis are awesome. I highly suggest it and would do it myself if they would come to Texas!

-----------------------------------------------------------------
Founder: BestBikeSplit
Amazonian
Quote Reply
Re: Does optimal pacing matter this much? [Mrcooper] [ In reply to ]
Quote | Reply
I live just off the course and ride it a lot. I don't display speed so it's hard to say for sure, but I wouldn't be surprised if it takes 20+ watts more to maintain your speed on Stagecoach. That road is in terrible shape. And every summer around July they dump fresh pea gravel on parts of the course so that slows things down too.
Quote Reply
Re: Does optimal pacing matter this much? [Mrcooper] [ In reply to ]
Quote | Reply
So I've adjusted to likely more realistic CdA settings and am within about a minute of the actual time now. 0 degree CdA of 0.3462, yikes!

Playing around with the bike setup on here gives a great sense of just how much time can be saved with a decent aero setup.
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
Now that seem really high. But if you try out with a few other courses you should see if it's closer.

-----------------------------------------------------------------
Founder: BestBikeSplit
Amazonian
Quote Reply
Re: Does optimal pacing matter this much? [Mrcooper] [ In reply to ]
Quote | Reply
Mrcooper wrote:
Now that seem really high. But if you try out with a few other courses you should see if it's closer.

Just ran Vineman 70.3 2013 with average power of 211 watts. Predicted was 2 hours 52 mins 11 secs . Actual was 2:53:20. Now I can't decide whether I should be depressed that my setup is so slow or excited that the algorithm works so well...
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
Good thing is there is tons of room for improvement get in with ERO and you go from .34 to .25 and at that power you are a machine!

-----------------------------------------------------------------
Founder: BestBikeSplit
Amazonian
Quote Reply
Re: Does optimal pacing matter this much? [tttiltheend] [ In reply to ]
Quote | Reply
tttiltheend wrote:
. I can average 20 mph on AP of 160 watts over rolling terrain with similar elevation gain, and I'm not super lightweight at 160 lbs. .

What?! Can you elaborate on your setup? I'm similar in size (weight) at 5'10". I have do more in the neighborhood of 190-200 watts to avg 20mph (cervelo P2, one-piece trimax aerobars - slammed, good REUTL fit). I WANT to be as aero as YOU! I'd be a freakin' superstar ;-)


-------------------------------------------------------------------------------------------------------------
"I can eat 21 plus a deep-fried turkey!"
Quote Reply
Re: Does optimal pacing matter this much? [Supersquid] [ In reply to ]
Quote | Reply
Yeah, you can pretty much just call most of the IMWI course roads "poop".

I guess that's part of what gives it character.

Fortunately other than stagecoach nothing even comes close to the crappiness of Racine, which makes stagecoach look like smooth tarmac.
Quote Reply
Re: Does optimal pacing matter this much? [Supersquid] [ In reply to ]
Quote | Reply
Supersquid wrote:
I live just off the course and ride it a lot. I don't display speed so it's hard to say for sure, but I wouldn't be surprised if it takes 20+ watts more to maintain your speed on Stagecoach. That road is in terrible shape. And every summer around July they dump fresh pea gravel on parts of the course so that slows things down too.

Really?... cool.. I'm well prepared then for Sept. No way those roads are worse than a couple of my training routes. I hope to preride it some time this summer. I'm sure it will be the day after they dump gravel on it. Loose pea gravel sucks to ride on.

My favorite is they last year this chip sealed a couple 1/2 ways descent segments of my favorite long route and the surface condition got a lot worse... I mean a lot worse. I couldn't believe it.

Bestbikesplit still has me doing 5:08 on a very conservative 212NP. I have trouble believing that time. I'm thinking it's closer to 5:15. Do I need to completely reload the course?

Actually the times for all my races seem just slightly optimistic for my power numbers. Maybe it thinks I'm just a lot more aero than I am. Shows that for my height & weight, that maybe I can make some improvements.

Otherwise I hope it's right. IF so, I'l have a sweet season and I'm just under estimating myself.


TrainingBible Coaching
http://www.trainingbible.com
Quote Reply
Re: Does optimal pacing matter this much? [sentania] [ In reply to ]
Quote | Reply
Quote Reply
Re: Does optimal pacing matter this much? [robr] [ In reply to ]
Quote | Reply
robr wrote:
So I've been playing around with BestBikeSplit.com and comparing the output to my recent race results. Long story short I can't get the predicted value to come very close to my actual race result. Here is a link to the BBS prediction: http://www.bestbikesplit.com/public-race?r=4115 . I've played around a lot with the bike setup and change wind/yaw angles quite a bit without any luck. Here is a link to my power data from Oceanside a few weeks ago: http://tpks.ws/lLrx . It seems like a lot of people have had good success with the site. The prediction around 7 minutes off and I can't seem to get things to go over 2:40. Does correct pacing matter to the point that you can gain 7+ minutes? I'm riding a road bike with clip on aero bars.

You need a means to parse out the differences between actual ride data and modelled data due to:

- inputs for variables such as CdA, Crr, etc, as well as wind and other course variables that might be different on the day than assumed in the model (that's tricky to do but possible if you know how)
- actual pacing versus modelled

If you paced pretty well, then the differences are more likely to be due to one or several differences in variables in the former.

I'd say the difference between a poorly paced ride to an excellently paced ride is worth perhaps 2% of total ride time depending on how badly you paced (the difference might be a bit more or less). Good pacing to excellent pacing is in the <=1% gain category.

Of course bike pacing in IM is not just about the best bike time for the available energy output/physiological strain, but how also it impacts your run.
Quote Reply
Re: Does optimal pacing matter this much? [Mr. Blonde] [ In reply to ]
Quote | Reply
Speed concept 7.2, Zipp vuka bull & clips, Zipp 404/808 clinchers, Conti GP4000s front, Vittoria evo rear, LG Rocket helmet (to be replaced this year). About 12 cm drop, arms pretty close. Although to be honest, unless it's windy, cold or pretty hilly I can do 20 mph on that wattage with a road helmet & training front wheel (Rolf vigor, the Zipp 808 stays on all the time as I can't deal with swapping pads on the rear brake). I do ride with a higher VI than what some people recommend. I go a bit higher on the uphills and on the gradual downhills I tend to stretch out with my hands on the shifters, turtle my shoulders, and spin at 75-100 watts, and I can go fairly fast and it's pretty much active recovery. So the downhills tend to bring my average watts down a bit but I don't push very big watts on the flats either.

When I got a PM it was a reality check how low my FTP was, but I'm older and it's results that matter, not numbers in WKO.
Quote Reply

Prev Next