OT, but I tested this ... and I discovered that the backpack is not necessarily less draggy. http://www.bikeforums.net/commuting/...l#post16092951

Strapped on top of a rack was the fastest configuration.

On my back, the backpack was less drag only when it was half full and rode low on my back.

I remember. You have a pretty leaned-over posture and so the backpack was protruding to create more drag. It made sense. It's why I prefer a tail bag. But (engineer getting picky), the conclusions of that post conflict with the first experiment where with/without pack had no effect, even though you were in the drops, when theory says it should have; and you don't have a no-luggage control group in the second experiment.

Awesome... took the low road with the Cascade to test the new crank setup.

http://www.ravingbikefiend.com/bikep...decommute1.jpg

In the first one, the pack only had some plastic wadding in it, less than half full. So it didn't protrude into the wind as much and hung lower. It was only backpack vs no backpack.

In the followup experiment I loaded it up with a commuting load: change of clothes etc, so it was fully expanded. I also switched from drops to more relaxed on the hoods for the second test, not leaning so much. I don't think that the results are contradictory, but reflective of the extra drag of a fully loaded pack.

I probably am leaned over more than most commuters so the full backpack would pop up more. That's a valid objection. But there was a pretty big difference there, with the rack winning. At the least I wouldn't choose the backpack for purely aerodynamic reasons for speed - if you're concerned about that, you probably do have a more aggressive position.

My legs are sore (12 hr hike Howe Sound Crest Trail on holiday Monday.)
I rode tues and wed, but today i'm resting them.

I thought I was tough hiking the HSCT in one day... turns out a guy we saw sprinting was putting up a FKT (fastest known time) of 3hrs 46mins which is mental. GaryRobbins's 3:46 h Trail running Move

Due to the rain, I opted for the car sitting in my driveway today. Probably the first time in the last 6 months I've done that. Of course I'm used to leaving at 4:30 to get to work by 5, so the only 10 minute commute today threw me off a little. I did manage to get a lot of necessary cleaning done while waiting for my distributor so all is well.

Well, today is my second day riding my new road bike. A Specialized Sectuer. An upgrade from my Roadmaster mountain bike. Leaving home at my normal time with the new bike, I arrived about 15 minutes earlier than normal. Wow this bike is fast compared to that old mountain bike.

I got nearly side swiped on my commute to work. I was at the stop light waiting for the light to turn green, and the car behind me decided it was a great opportunity to pass me. Very close! She had her window down and I gave her a piece of my mind.

Well, it took me 3 minutes longer to complete my 6.5 mile route. So, did I just break the laws of physics? What does that mean?!

I need to go rethink my life.

Three minutes moving time or three minutes total time.

Regardless it could be wind, fatigue, stop lights and other traffic which you get unexpected drafts from.

In my years of riding a few minute deviation is not unexpected between rides.

Were you carrying more stuff on the rack than you would in backpack? Did you cause misalignment of your brakes while having the rack installed? Some cable routing may have been shifted causing brake drag. Has this time increase been reproducible and consistent?

I did a test this morning. I am always around 20 minutes and 30 seconds to 21 minutes on my hybrid bike. I have been building my legs for a month or two now and wanted to see what I could do. With my laptop and everything on my back I rode my road bike and was able to make it 5.7 miles in 19 minutes this morning. That is a record for me so I would call that a good commute

How were you positioned in the lane? Centered, left or right of center, right edge?

Uneventful commute in yesterday morning. Had to make a short detour by the office to stop by Kroger and get some more coffee creamer that I use. Coming back I had to cross the road going towards the elementary school, and it was the first day of school. Traffic was backed up like crazy. I was only crossing that road, so it was nice being on my bike such that I could just sneak through traffic.

During the afternoon yesterday we had some massive rain showers and storms. It slacked off and quit by the time I left at ~4:30, but the radar showed more coming so I was sure I was going to get rained on, which I was hoping for because I love riding in the rain during the summer. Just as long as it's not storming. I rode 15+ miles in under 70 minutes and it never rained on me at all!! :notamused: I made fairly decent time, though. Seemed like more traffic than usual on this one stretch of 2-lane road between the interstate and parallel state highway. Lots of control and release going on yesterday.

Also used my new Canari shorts I got on sale from Nashbar last week. So far they seem to be pretty good. Chamois is a bit smaller than the one in my Louis Garneau shorts, but that may actually end up being better for me.

Still a bit muggy, but not so bad this morning. Possible showers this afternoon and over the weekend.

On the way home yesterday I stopped to pick up a wire on the side of the road. Just a simple headphone style patch wire, but I can use it to connect my phone to an iPod player.

This morning I had a few extra minutes so I wound my way through a neighborhood that I normally cut straight through. I like knowing different ways around and such because you never know.

Thanks.
One thing I realized i need to do is plan for home emegencies. Taxi cab/company car.

Congrats on that achievement.
I've decided morning commute will be my TT training and evening LT/interval, next day recovery on so forth.

Good questions. I downloaded the data off of my Garmin, and with a backpack I was averaging about 13.5 mph going and 14.9 coming back home. (I usually take more stuff with me to work than I bring home, and the return trip is more downhill.) With a rack, I averaged 12.6 going and 13.4 coming. Mind you, I've only used the rack on 2 commutes, so I had limited data to work with.

Instead of a trunk bag, I have panniers sticking out on the sides of my rack, so I'm sure they create much more drag than the CamelBak I used. That's the only thing I can figure. That and because the weight is on the back of the bike, maybe there's more drag on the back wheel instead of evenly spread over the entire bike?. I don't know why, but suddenly I'm slower.

No discernible difference for me whether I use a backpack, rack and trunk bag with expandable panniers, or nothing at all. I'm almost always 12-13 going in, and 13-14 coming home.

Too be honest it wasn't that great a commute this morning. Having overslept by about an hour, I rushed out of the house and decided to save time by going slower and taking the long route. The shorter route involves traffic lights, and to save time I have to sprint catching them, and also stay ahead of city buses. So I skipped the fitness center stop and shower, changing in the restroom instead, saving around 10 or 15 minutes, bed to desk. It is still wet and sloppy from the rains, and riding through mist or fog.

On the bright side it marks 300 commutes with only one day driving, and I'll hit 200 consecutive commuting days on the bike on Monday so it feels like I at least accomplished something.

WOW amazing!!! I really, really wished I lived and worked where I could ride to work 5 days a week.

I hang mine down from the top tube, ironically the one configuration I didn't test but I believe is the most aero one. I'm averaging 18.3 +/-.2 mph on most commutes home, but in the larger scheme of things it would still make no difference in total time. Seconds.

That is very interesting. I would not have expected that. I wonder how much drag actually plays a role.

Mind you I have almost exclusively used panniers and racks.

I would be curious to know if it changes much over the next few weeks.

Well time to move my day to the sunny ocean view. Last day house sitting an ocean view.

You hang what from the top tube?

My commute stuff. It's a lightweight drawstring bag, where the cords run through grommets at the four corners. I put hooks on the cord at the bottom corners and I just loop the cord around the seat tube, hooking back into the grommets. At the top I loop a strap around the head tube. So it's actually a thin frame bag/backpack that goes on and off in seconds. I mainly just hate wearing a backpack, and didn't want a rack on my road bike.

17degc (62degF), mostly sunny. minimal traffic. Beauty day!