Commuter bike delima

[jazclrint]

Hey all,
I am a new wireless iSport owner. I just mounted it today, but have yet to use it. I needed a computer and decided to go with this. I sold the parts off my road bike this summer (school you know) so my road/trainer/CX/commuter bike is a Bianchi Axis. My question is how should I set it up when it comes to total weight. When I commute I have it loaded with bags. I'm currently a music ed major doing my student teaching, so I have music, instrument, shoes, food, ect. on my bike. I take all but one bag off when I go on a training ride. There is a significant weight difference. I also have a Mt. Bike I plan on putting the iSport on. I only have 2 profiles on the iSport, and no way to load different ones. Right now I have set the total weight at my training ride weight, and I'll just deal with the off power numbers on my commute as it's really not important. I just want to keep track of mileage and time, but on my training rides I want accurate power. Really, if I wanted too I guess I can change the total weight between the loaded and unloaded weights. Any problems doing this? Any suggestions on a more efficient solution?

Thanks,
Rich

[lorduintah]

Get another iSport. or -

Get a cheap computer to track your mileage alone. You only need to spend 30-40 bucks for miles.

Tom

[R Mc]

Or . . . don't worry about it that much. The extra weight will affect power reading most on uphills--and even then it's not THAT significant.

What's more significant is if the packs drastically affect your wind exposure.

[jazclrint]

There's a reason I waited and bought 1 computer, and I wouldn't spend more than $20, but more like $15, for something just for mileage. I also wouldn't buy a new iSport, I'd upgrade it to an iPro so I could have as many profiles as I wanted.

Thank you for the tip about the weight. I really don't feel the bags cause that much of an aero drag because of the size and position behind me. Besides, when I commute it's an extra 30 lbs and I'm only averaging 11-13 mph. Not much cause for aero concern at those speeds.

Funny thing is I'm geeking out on my watts on the short commute. Mostly because it'll be reading watts when I'm not pedaling and reading zero when I am (for rather lengthy amounts of time). But, I'm certain this is mostly due to my tire dynamo I just put on the same day I mounted my iSport. I am also not running road tires, but Schwalbe Marathon Cross's, which I'm sure are not as efficient as normal road tires.

I have more calibrating and experimenting to do, I know, but is there any reason I can't just change the weight and friction numbers for when I go to commuting (w/bags and dynamo on)to training (w/o and off) setups?

Thanks,
Rich

[lorduintah]

If you want some semblance of real values - yep - just make the updates for the type of ride you are doing. Get the extra calibration once, then you can manually make the changes as desired.

Tom

[Russ]

If you go ahead and do calibration/cd's for each setup, then keep the two profiles that you are most interested in seeing on the bike results with in the iBike then.....

You could tweek back at the computer during post ride analysis using the correct values from the profiles that match the ride to get corrected numbers for the training log.

If you actually change the numbers in the iBike manually, you have to carefully keep track and put back what you need each time... I tend to screw that type thing up from time to time .

Russ

[lorduintah]

Many reasons to upgrade to an iPro seem to be cropping into this. Having the software and store of profiles which can be downloaded to the iBike as appropriate seem to fit into your needs.

Tom

[jazclrint]

I know, but the budget just isn't there. I was pushing it getting an iSport as it is.

What numbers do I need to change? I have the 2 weight values. If I do a coast down test in each configuration what numbers do I need to write down?

Thank you all for the reply's.

[jazclrint]

I found a major reason for my problem is my handlebar bag. Even though the iSport sits, what you would assume, is far enough above the bag Wind speed was reading 0 mph, until I pushed the bag down a bit. Time for a Topeak Xtender.