Auto tilt and hill repeats

[GWPOS]

Just wanted to check and see when or if they had the fix for hill re-peats where the numbers are low when starting a second or third hill repeat after having come down the hill. This is most noticeable on hill climbs of more than 10 min or so. I know Travis had mentioned he had a fix for the algorithym that did this calculation. Thanks

[Velocomp]

Please post a ride file.

[GWPOS]

Here is a ride file with one long interval and a 2x10 interval set. However after coming back down each time I road easy for 5 min back up before starting my interval because if I don't then my wattage numbers are reading to low and I end up going to hard which makes it hard to complete intervals (not so much on 10 min ones but definately on all out 20 min intervals it does). The bad thing is that if I am only supposed to have a certain amount of recovery in between I have to try and account for the extra 5 min it takes for the unit to recalculate the tilt properly. Anyways I have been through this before so i will not keep going into it. I have attached the ride file mentioned above and another one where I did 2x20 on a nice incline. Both of them I took into consideration about the tilt so I waited 5 min before starting the secon and/or third climb.

iBike_01_13_2011_1736_29_Miles.csv

(1.61 MiB) Downloaded 362 times

iBike_10_30_2010_290w_266w.csv

(1.84 MiB) Downloaded 340 times

[travispape]

Just wanted to check and see when or if they had the fix for hill re-peats where the numbers are low when starting a second or third hill repeat after having come down the hill. This is most noticeable on hill climbs of more than 10 min or so. I know Travis had mentioned he had a fix for the algorithym that did this calculation. Thanks

I looked at the ride files and indeed the new algorithm is working well and improving the data. The improvement is greatest for the 5 minutes following the turn around at the top of the climb, and in both of the ride files that you sent, the new algorithm prevented an error in the tilt of 0.5 to 1.5% compared to the old algorithm at these turn-arounds.

Travis

[GWPOS]

Hi Travis, and thanks for responding back. I just wanted to clarify that it is not so much the turning and going back down that I have a problem with, but the going down and turning around and heading back up. I notice that the unit shows me about 30 or even more watts less than what I am actaually doing. If I turn around and start heading uphill I still have to wait for 5 minutes before doing my next interval before the watts are right. I waited the 5 minutes before starting my climb on the previous ride file post. Like I said if you are doing threshhold intervals and go harder than you should you end up cooking yourself and not being able to do the whole interval. If I was to just start my interval with out letting the unit auto correct the tilt for 5 minutes I would be pushing 30 or more watts more than I should for 25% of the interval I am doing. I sure hope I am explaining this in a way that is understandable. Thanks again for your input and efforts in this matter.

[racerfern]

I have a comment/question:

Since I do similar intervals I can't say I've seen this problem. I'm wondering if the speed coming down the hill has anything to do with it. IOW I can do the interval and come flying down the hill at which point I have to doodle around at the bottom or I can manage my downhill speed so I arrive at the bottom about in time to start the next interval. I tend to control the downhill speed and the length of the rest section is usually longer when I do longer intervals giving me plenty of time to get back to the bottom.

[GWPOS]

I can go down fast or take my time and recover, it does not matter. Its after I start going back up the hill that I have power readings that are to high. I have to start going uphill for 5 min and then the readings fix themselves, at which point I then start my interval. Kind of confused as to why I have to wait this 5 minfor the unit to "catch up" so to speek.

[rruff]

The iBike is getting confused about the tilt when you are going downhill, which could be caused by brake use or rough pavement. So it adjusts the tilt incorrectly and doesn't sort itself out until you've been riding back up for awhile.

You could solve that by tooling around at the bottom for a few minutes. Or if you get your riding tilt perfectly dialed you can reset before each run.

BTW, I don't stare at my PM when doing intervals... pace by feel and look at the numbers later.

[GWPOS]

Sorry John about not posting for awhile, but here is an example of the auto tilt being behind and causing problems for me during hill repeats. During at least 2 of the intervals (which were only 4 min long instead of the usual 20 min..was doing VO2max intervals) the unit showed I was only averaging 307/308 watts. After the download it changed to 320 or something. My unit was showing to little watts and I was almost cooking myself trying to reach my wattage goals at the beggining of the interval. I also did a 20 min tempo interval at the end and for the first 4 min the numbers were again too low. I have attached a ride file for you to play with if you get a chance.

iBike_03_01_2011_0647_22_Miles.csv

(1.4 MiB) Downloaded 336 times

[GWPOS]

Just wandering John/Travis if you have had a chance to look at my file yet?? Thanks

[rruff]

During at least 2 of the intervals (which were only 4 min long instead of the usual 20 min..was doing VO2max intervals) the unit showed I was only averaging 307/308 watts. After the download it changed to 320 or something.

Surely you aren't complaining about a 3% error? I get more scatter than that. I also don't look at the unit while doing intervals... it's much better to pace by feel.

But if you want to you can reset your trip each time and it will always be good. Have you tried that?