Road Surface

[barry6054]

Hello,

Has anyone experimented with the road surface choices in device/set-up?? I have recently moved and my new routes are on roads that are much rougher than the old routes. In fact there is one 5mi stretch that will shake your teeth. I did some sub-threshold intervals yesterday on the stretch and my effort level felt more like FTP and even above. There is very little traffic on that road so it's a great place to test other than the rough pavement. I'm going to set up a new profile and change from good asphalt to rough pavement today but will not have a chance to actually ride that road until next week. I'm wondering what kind of difference I can expect to see in power using the rough road profile. Thanks to all!!

Barry

[Velocomp]

You can simulate the effect in Isaac. Go to Analyze/Tweak CdA, Crr...

Set Crr to around 0.008, the rolling resistance of a rough road, and you'll see how that affects your watts.

[barry6054]

Thanks for the quick reply John! I made the change last night and will get a chance to try the new Crr setting on Fri. Stuck on the trainer until then.

Thanks...Barry

[Russ]

Barry,

Besides changing your profile, I believe John is suggesting you can post analyze that ride you mentioned with a tweeked CRR.
In other words, use the analyze/ return to original download choice then choose tweek values and change the CRR to the .008 and observer if the power levels appear more ballpark. You may find .007 or .009 or someplace in between besides .008 is better still.
You can optionally save the tweeked ride to keep that analysis or bail out to discard.

Russ

[Pete]

If Crr is too low would that not be apparent via Isaac indicating "braking" where it should not?

[Velocomp]

If Crr is too low would that not be apparent via Isaac indicating "braking" where it should not?

That is a distinct possibility, though you'd then have to know where you really were braking, to separate applying the brakes from the high Crr.

[barry6054]

Thanks Russ and all! A couple of days after I first read John's reply I figured out he was talking about tweaking the Crr on a file already downloaded before I edit or create a new profile. I played around with that and it makes a pretty big difference. On my 40 plus mile rides the road surface can be anywhere from very smooth to very rough and harsh. I'm working on finding a happy medium and then leaving it alone. I also need to test on the same stretches of road so I'm comparing apples to apples every time. Again, thanks for all the help!!

Barry