Ok here is the question. Same rider, bike, backpack, all the same and they ride same route, and weather/temp. And all identical but 1 trip the weight load is in backpack and the other trip the same load is attached to rack. Total weight both times are same just distributed different either on rider and bike is light or on bike and rider is light.

As for me I feel faster carrying load in my backpack and not on track. "I think it's a mental thing."

What are your thoughts or has there been funded studies?

What i have found from personal experience:

* Set up: Laptop + some little stuff in a biking backpack - meaning the weight is where it should be (low), comfortable vs Rack + lightweight pannier with laptop and shirts in there.

Case 1: 80 kms ride on the relatively smooth asphalt roads - rack is better, after some 50 kms of riding with backpack I feel that i need to stretch my back quite often, which slows me down. Not a deal breaker, especially if it's only 10-20 km, but a rack + slim pannier work better.

Case 2: City streets only - I find that backpack is a better option, "naked" bicycle feels more agile, especially if you cut the corners and have to jump a little bit, less time wasted getting the pannier on and off, all the precious stuff is with me 100% of the time, nothing rattles, etc.

I've no idea if there are studies, but I can tell you since I bought a basket and started just putting my backpack in the basket life has been so much easier than riding with the backpack on. Much easier on my back, too after each 13 mile ride.

I feel faster since doing that, but that could also be just because I was riding with the backpack in the beginning and have gotten faster in general from being in better shape.

Edit: I should point out I don't normally carry a laptop, so the backpack's just carrying clothes food and tools. If I have to carry a laptop, I put it on my back to protect the laptop more from the bumps.

There are a few variables the OP didn't control for, e.g. the type of backpack shape (some are quite square and carry weight up high on the back, others are sloped and carry weight lower), how the load is carried on the rack (pannier or trunk), and if pannier, size, type, and single or double. All of these would make a difference, I'm sure. Or how about my setup, with a seatpost mounted Xootr Crossrack which tucks a pannier perpendicular to the bike behind the thighs and up against the butt?

All that being said, my guess would be the right trunk pack is fastest, followed by the right backpack, then Xootr, then dual panniers.

I'm not aware of any studies, but would be interested to know if this question has been tested, too!

My instinctive guess is that the load on the rack is faster than on your back, but control feels easier with the backpack. Also, with regard to the feel, there may be an analogy here with lighter frames "feeling" like they accelerate so much more easily than heavier ones when the actual difference is slight. But it seems more responsive, quicker.

If we can ever get a nice weekend here again and I have the energy, I think I'll do a coast-down test. I don't think the weight distribution will make much difference but the aerodynamic drag will change measurably.

Sit them side by side and wait till one moves..


Fast is about the rider turning the pedals ..

As is rack/pack preference. I'm a shoulder slung messenger bag commuter.

I agree with Mikhalit in post 2. The more your commute looks and feels like a section of a bike tour, the better suited racks become.

Doesn't make a difference for me. I've got a big ol' messenger bag that I use sometimes but mostly carry the same **** in a set of panniers on a rear luggage rack. I can't detect any difference in speed, though my back doesn't get as sweaty when I use the panniers.

I commute in NYC about 4 miles each way. Lots of traffic, lots of lights. I use an older road bike with drop bars and decent modern rims. When I started this routine, I was carrying my laptop and clothes in a backpack that also tied off around my waist, taking weight off my shoulders. It was great, but more recently I switched to a rack, to which I secure a mid-size bag carrying same load as above with a few other bits. To protect the laptop from road shocks, I line the bottom of the bag with a sheet of packing foam.

All in all, the weight strapped to the rear of the bike definitely compromises handling. It's not nearly as agile, but it's not bad. Most days, I now carry substantial extra weight in the form of a large heavy lock and chain and I just never bother taking it off the rack. Once up to speed, the aerodynamics of the bag secured behind me instead of on my back seems to yield better top speed. I can get lower on the bars, which I like, without the bag getting out into the air stream, nor pulling on my shoulders awkwardly. In the end, it's all personal preference of course.

I hope to find out when I either finish my homemade rack or decide to pony up big bucks for a pre-made rack. I like that Topeak rack and basket that joyota posted above, but my local REI wants a fortune for the pair. I might end up with a milk crate instead, but I digress...

My biggest gripe about a backpack is the discomfort but also the sweat it produces. One day two weeks ago I brought an entire set of clothing the day before and then rode to work the next day with no pack at all. My shirt was almost dry when I arrived. But, with the pack, I could probably literally wring sweat out of my shirt from the huge wet spot on my back where the pack sits.

I realize this has nothing to do with "fastest" at a glance, but my thinking is that a more comfortable rider is a faster rider, all other things being equal.

lmao
Thanks again, fietsbob.......

I've tried both, each for a few years. No speed difference, one is just more comfortable.

perception is reality

For shorter distances with a lot of maneuvering and some off pavement excursions and a need to keep my stuff with me, backpack and yes, I also think it might be a touch more aerodynamic, thus faster. LC

It should be less work with the load on the bike rather than supported by your torso.

Without any backpack or bag attached to my body I feel much more comfortable and free to move. When carrying a backpack, I tend to use one hand to adjust it to relieve my shoulders from time to time. Much worse in hot summer day with sweat on the back: keep lifting the backpack from the back to cool off. In short: unwanted hassles come with a backpack that can affect speed (by a little) and safety (more concern). But it obviously save time when parking the bike.

When it's all said and done, it's about the rider. I have a 6 mile commute and I normally do it in 28-30 minutes. One day I decided I wanted donuts on the other side of the city so went to the car and the battery was dead (left my lights on), well I had my backpack on and knew I had to be at work so I booked it as fast as I could with 12 lbs on my back (backpack weight is 4lbs). I made it to work in 24 minutes. I guess it comes down to if you're motivated or not, I guess I was that day!

Don't know about faster, but my butt hurts more when I'm wearing a backpack. As for the rack, mine is a side wearing variety, so I'd expect balance could be thrown off with a heavy weight on it.

The rack'll have a lower center of gravity.

Trunk rack and backpack probably a tie.

Pannier will be anti-aero compared to a backpack, so probably slower @ same rider power output measured @ cranks.

Some backpacks will make you slower. Some sloppy backpacks you can't even stand and pedal with, good ones with sternum straps and good load handling will let you go anywhere.

Need to hit a couple of shops enroute then backpack wins more time since you don't have to remove panniers or trunk bag from rack upon arrival at each store, then remount them upon departures.

No idea which is faster, and it's not a factor in my decision. Just comes down to personal preference. I'm more comfortable as a rider not wearing the load, which I did for many many years, Now, I commute with a rack and bag. What ever floats your boat.

I have done all three and I'd rate them backpack, trunk bag, pannier in terms of pure performance. That being said, the backpack has to be a good cycling specific one and not overly large (more than 20L). I just started using a Dueter Air EXP and it's great for my commute. My issue is that I like to switch bikes too often and having racks on all of them is just too much of a pain. The Dueter distributes the load well and keeps your back from sweating.

My trunk bag also works great, but other than having to have a rack for each bike, it puts the load up too high and makes for some funky handling. Aerodynamically it doesn't seem to hold me back though.

Panniers do get the load off your back and down low, but handling is still affected and aero drag goes way up.

10 mile commute each way, only carry clothes (no shoes) and lunch.

And that is what it boils down to- personal preference.

I've worn backpack and messenger bag, strapped the backpack to the top of the rack, backpack in a grocery pannier, and used a trunk bag. They all have their pros and cons.

As far as the difference in aerodynamics... I haven't been able to get to wind tunnel to do a controlled experiment.

Don't know if he used rigorous scientific methods, but several decades ago Jim Blackford showed that putting the load down low and distributed front/rear affected bike handling less than high and to the rear only. Don't guess that commuters will be much inclined to adopt loaded cycletouring techniques. The takeaway is probably that lower is almost always better than higher. For a while in the 80's - 90's I commuted with the load in front panniers on a lowrider rack.

I'm gonna presume that's more important for loads over 25 lbs or so. I'm sure some commuters haul that much to and fro but I'd advise against it if at all possible.

I've had big loads up high and back and yeah, it gets squirrelly. Had to kiss the stem to get reasonable front wheel response.