Just curious. My bike with fairly loaded panniers weighs in around 40+ pounds, maybe almost nearly 50 pounds. If the wind is fairly calm, I usually ride an average of about 15 mph. With a tailwind I can often go as fast, on average, as about 18 mph with jaunts up into the 23-27mph range. Days where the wind is right in my face kicking the crap out of me, I'm lucky to be doing 13 mph average, although that average is skewed by a couple occasions where I can get a higher speed in. Most of the time when I'm cruising along fighting a severe wind I can look down and see that I'm really only going from 10-12 mph at most. Just wondering what other folks on heavily-laden bikes are doing. I always mutter a curse under my breath when I get passed by someone who's just zipping by making it look all effortless. Usually that person zipping by and passing me is someone on a "race bike" (mine is a touring bike - fenders, racks, etc.), with a backpack and no racks or fenders or panniers that create all kinds of wind resistance. So, I mutter and grumble, but I figure I'm doin' pretty damn well considering the load I'm pushing along.
New here, and first post, I actually joined to respond to this topic. Hopefully I will find other useful info here as well.
I come from North Center and commute to Navy Pier. I ride pretty loaded, not sure the weight (40lbs?), but steel commuter, rack, panniers with bags and backpack. But I have noticed something strange. With a backpack on my back, I am a bit slower. But that same backpack in my pannier bags I am a bit quicker. I have averaged about 13 mph over the last few weeks. I try to maintain that as my ride is about 6 miles and it gets me there in about 30 minutes. Without wind I can maintain 15-18mph but I try not to get sweaty before work.
On the way home I kick it up a notch. Without the wind in my face I have hit up around 26 mph. Thats a short burst after a good downhill through LP, though. Wind seems to be the biggest factor-we all know- but weight is certainly a factor.
I commute with a similarly equipped and loaded (and heavy) touring bike every day (although not on the LFP) and average similar speeds. I think weight affects acceleration more than speed. The panniers exact a heavy aerodynamic toll; I can feel a marked difference when I ride without panniers. I use upright bars rather than drops. I would say that my general average speed is about 15.
As to backpack vs. panniers, I'm not sure about the aerodynamics or anything. All I know is that I feel less constrained on the bike when I have all my load in panniers. I, too, feel faster without a backpack. I attribute that to having to use less energy to maintain a good position on the bike, and that translating into more efficient power transfer.
But it could all be in my mind.
Jimmy Jam said:
[snip] With a backpack on my back, I am a bit slower. But that same backpack in my pannier bags I am a bit quicker. [snip]
I've wondered about the backpack thing too. I see lots of guys using them, especially the fancy roll-top backpacks. Anyway, I imagine a backpack probably is slightly more aerodynamic, however, as was previously mentioned, you have to work more to maintain a better position. In the past I've used a Timbuk 2 messenger bag (the big one), as well as a backpack. I never felt that comfortable with either. They make me feel constrained and poorly balanced. Sure, my panniers catch a lot of air, especially on those fierce headwind days, but I'll take them over a messenger bag or backpack any day.