Tuesday, October 14, 2014

Is Uneven Pannier Load Problematic?

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When I ride a pannier-laden commuter bike, it is not uncommon for one side to be bulging while the other sits nearly empty. This is not because I can't be bothered to distribute the weight evenly, but because one of the panniers houses my enormous photo/laptop bag and I don't always have anything to put on the other side to compensate. I've cycled with this type of uneven rear load pretty much the entire time I've owned bicycles with rear racks. In the past, I've usually had a briefcase-type pannier clipped to one side of the rack, with nothing on the other, which is really no different from having unevenly loaded double panniers. But it's when I switched to the latter system that observers really began to notice. Over the past month in particular, I've received quite a few questions and concerned comments about the issue! These tend to fall into one of two categories: (1) Does the weight not pull to the side and cause handling issues? and (2) Isn't the uneven load bad for the bicycle frame?

Speaking from personal experience, my answer to the first question is "Usually, no." When riding an upright commuter bike - even a fairly lightweight one like my 25lb mixte - I simply do not feel the asymmetrical pannier load (typically 10-15lb on the lefthand side - though on other bikes I've tried as much as 40lb) once the bike is in motion. I do feel it when walking the bike. And it makes keeping the bicycle upright on a kickstand tricky. But once I put foot to pedal, the weight more or less disappears and I think nothing of it. Even when cornering, I've never felt it to be a problem on this type of bicycle. That said, I have not tried riding a roadbike, at roadbike cornering speeds, with the same setup. I can see how in that context the weight disparity could be problematic, and I'd be curious to hear from cyclists who have experienced this for themselves.

As far as an uneven load being bad for the bike… I imagine that would depend on lots of factors, including what sort of weight the bicycle was built to accommodate in the rear, and how chronically, as well as for what distance and duration, the owner rides it unevenly loaded (assuming the weight is always on the same side). I have seen a few twisted vintage frames, where it had been suggested they got that way through chronic uneven load carry. But without knowing the owner, it is impossible to tell for sure. My own commuter bikes have all been fairly stiff laterally, and I've never feel any twist in the frames as a result of uneven weight at the rear. But these things are not always perceivable, and it hasn't been long enough to gauge long term effects. Just in case, I try to alternate the side of the load and never make it ridiculously heavy.

In general, I would say that the average utility bike can certainly handle uneven rear load distribution, and as long as you feel comfortable with the bicycle's handling there is no need to worry. As always, YMMV, and I welcome others to share their experiences.

45 comments:

  1. Panniers like yours stick relatively close to the bike. You would get more balance problems should you hang a bag on the end of your handlebar.

    I remember from the olden days, when I had a paper round, that the special panniers used for that could spread so wide -- especially on the weekends -- you had to be careful to pick the newspapers not just from one side; because that could disturb the balance eventually.

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    1. Well, there's a fundamental difference between hanging weight from your handlebar (where it operates on trail to steer the bike) and on the rear. I wouldn't want grossly unbalanced front panniers, either.

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  2. If it's reasonalbly secure, I've run offset loads of up to 40lbs without issue (softener salt on a longtail). Like you noted, the hardest part is walking with the loaded bike.
    What I've found to be the worst is any sort of load that can swing, like a heavy grocery bag on the handlebars, or a heavy load held by hand, like a 5 gal bucket of flour. (Wife bakes, I haul. Its a good arrangement)

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    1. Yes, never pedal with bags dangling from the handlebars. An accident is sure to find you. I'm always more worried about front loads than anything going on in the rear.

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    2. It's your life, it's your bike…Just sayin' I don't enjoy falling off my bike and the only accidents I know could have been avoided where those where I tried to transport items in a bag from my handlebars. Strangely, it's eerily easy to unclip when something unexpected comes up, but instincts, for me, fail with dangling items. YMMV...

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  3. Sometimes I feel like people are trying to find problems where there aren't any.

    I've been riding with my fully loaded Racktime bag ( http://bostonbybike.blogspot.com/2013/02/racktime-workit-classic-pannier-review.html ) attached to the rear rack daily, for over almost 2 years. I never even thought about uneven load on my bike. I simply don't feel it when riding, even though I carry lots of stuff in that bag including a u-lock.

    And uneven load being bad for the frame? How much weight do you carry on one side? Those few extra pounds would twist the stays of my light rear rack, if anything, not the frame.

    The only time when uneven load may present a problem is when my bike is standing, supported by the kickstand.

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    1. On the Minuteman Trail, some time in the last days of September, a bearded man on a befendered roadbike actually shook his head at me, as he said, with a mixture of sadness and disapproval, "You should really distribute the weight in your panniers evenly." I smiled and gave him a thumbs up, as the glorious autumn sun bathed us in its dappled golden light...

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  4. Yes, I can't say I've ever had any issues cycling with unbalanced rear panniers and there is plenty of times I've only had one pannier on the bike as I haven't wanted the hassle of carrying two when going into shops and know I can get everything into one.

    I've only really noticed it when I'm off the bike and am manoeuvring it against a stand to lock it, or something like that.

    There is probably some physics to explain this but I don't know what it is!

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  5. I ride a fairly light mixte commuter bike and I did find that unbalanced panniers threw me off in a way they didn't on a heavier hybrid bike. I resolved the issue by gettin a Burley Travoy trailer...which I love. But, because I'm short I had to remove the rear rack to accommodate the trailer design. So, when I have a light load I use a backpack...but I miss being able to use a pannier. Still trying to find the perfect solution for one bike.

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  6. Mrs. S rides with panniers and often one or the other are used exclusively, and she's never once mentioned any balance issues.

    One of the key reasons, I suspect, is that with panniers, much of the load is near axle height, and being that low, it minimizes the effect of changes in center of gravity.

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  7. I had a lightweight road bike, built in the late 70's that I rode for commuting until six years ago, always with panniers and usually with and unequal load. For thirteen of those years I lived in a very hilly town which taxed every bit of my bike and strength (oh, btw, for two years the rear rack was replaced with a child seat in the same town)…Bottom line is I never had any issues with stability or control while riding, (I'm no daredevil though very comfortable on a bike), and as you said there were more issues with walking the bike or picking it up but never while riding.

    I still have the bike and the only clear signs of constant pannier use is where the paint had been worn off the seat stay after continued rubbing. I just put some padded tape around the area and kept pedaling. If the frame material had been fatigued it was not apparent to me.

    That bike was replaced with another road bike and much better quality racks and panniers and I've noticed the ride to be even more stable compared to my old set up. So, I'm guessing have better quality equipment does more than anything else towards making the ride stable. If the rack is meant for heavy loads and the bags are well designed to stay securely attached I can't image problems for the average user….

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  8. Seen a few broken racks do to excessive use and loads but never bent or broken frames.

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  9. Picked up a load of lumber at Home Despot once, but forgot to install my second wideloader, so I had to carry 160lbs all on one side, with a good fraction of that weight further out than my pedaling foot. Picked up my daughter at her music lesson and told her to ride side saddle to help even that out.

    Also once carried a shrubbery about a mile, all on one side, was too heavy for one person to heft it onto the bike but don’t know what it weighed:
    https://flic.kr/p/8VtMBB

    In both cases, the bike was well displaced from vertical, which did affect the steering somewhat.

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    1. Ah Xtracycle shrubbery.

      During my short lived ownership of an Xtracycle Radish, I once carried a 50lb-ish roadster bicycle on one side. The Xtra was so difficult to roll thus laden, I thought surely it would never work. But once I took off, it was totally fine the entire 9 miles home, except for a bit of heel strike against the front wheel of the roadster (those things are looong). Sadly, this glorious portage went entirely un-photodocumented.

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    2. "Sadly, this glorious portage went entirely un-photodocumented."

      You realize that by documenting that event with a camera you would have prevented it from ever reaching it's theoretical potential. That fact that there is no limiting documentary evidence allows that bicycle/load combination to grow and expand to whatever the limits of the listeners willingness to believe are.

      I contend that without people who are willing to act on the assurance that certain incredible feats are in fact credible, within the grasp of persons willing to over-ride received wisdom and common sense, than we will never know what we as a species are truly capable of.

      For example, if you tell enough friends that you portaged a 750cc BMW motorcycle on that Extra-cycle, the vast majority would think you were... A) Drinking,
      B) Unfamiliar with Motorbikes in general and BMWs in particular,
      or C) Likely to have your undergarments burst into flames.
      But, and this is a very BIG but, one or two of those people might BELIEVE you and one day attempt the same feat AND SUCCEED! How cool would that be? Your former fib would now be validated as truth and the manifest of amazing human capabilities would be one entry longer! A great service to Humankind accomplished BY YOU with no uncomfortable physical effort on your part! Now, in the future cargo bicycles would be seen to be even more useful than previously thought and any Bullshit you feel inclined to spread will be greeted with at least a smidgeon of strained credulity. A useful thing in this complicated world.

      No, you have done a fine thing by leaving the Minox at home that day and deciding to ferry that Motorbike home via pedal power.

      Brava!

      Spindizzy

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    3. (same quote as spin but too lazy to c/p)

      So, the one oppty. to document an epic portage gave way to innumerable, dainty snaps of laptop bags (I can carry a MacBook Air!!!).

      Your priorities definitely got scrambled on that one, not to mention you never mentioned it in numerous Xtracycle postings and thousands of words. Now? Really?

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    4. I now, I know. Next time I tell this story, it shall be a houseboat.

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    5. You actually could portage a 350lb. motorcycle with an Xtra Sidecar, but not a BMW. Everyone knows they add 200lbs. of Magic into each one.

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  10. I use a kitty litter bucket configured to hang from a rear rack on my early 90s Raleigh 12 speed (converted to a single speed) while commuting. Never having actually weighed it, I would guess it has 15 lbs in it. There is a slightly perceptible tendency to make cornering toward the side where it is hanging easier and slightly harder away from the side it is hanging. It is noticeable for probably less than a second and then it's gone and forgotten about.

    Walking with the bike and leaning it against something is a whole different story. Lots of care needed then.

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    1. Assuming that you are not in fact Mike "The Bike" Hailwood speaking from the grave, I warn you that if you are going to use that name, and don't let me stop you, you had better not be attempting irony. You need to be flinging that kitty litter laden Raleigh at the scenery at some frankly unfeasable speeds, coasting some hairy mountain roads with both tires sliding, your back flat and your inside knee dragging before stepping off at the bottom to perform astounding feats of drunken-ness and debauchery. It is a fearsome responsibility to live up to that name, more than I would attempt.

      Do it justice.

      Spindizzy

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  11. I always ride my commuter with unbalanced panniers. I do have a balancing problem sometimes when starting from a stop, otherwise, never.
    The problem for the bike would not be the frame. Rather, the spokes could, theoretically, experience a lateral load, similar to that experienced by wire wheels on a car as it corners. Or the bike experiences when the rider stands on the petals and pushes the frame to one side, then the other. But it all seems to within the design parameters.

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  12. Once upon a time people though that gyroscopic forces were essential to staying upright on a bicycle. Turns out its not so, but gyroscopic forces are a reason why uneven loads cease to be felt as soon as one is under way.
    About the frame being bent under uneven load ... it could in theory happen if the bike suffered a heavy impact (e.g. a pothole hit under speed) and the stays on the side with the heavier load entered plastic deformation while the stays on the other side stayed just below the plastic limit. But this scenario is rather contrived, there are many other (dynamic) causes of asymmetry while riding. Such plastic defomation would be an instantaneous event, as in a crash. Metals don't suffer creep and an uneven load cannot lead to frame deformation over time unless your frame was made of wood or a similar organic material. Even in the latter case loading would be less significant than stresses from uneven exposure to the elements, for example.

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  13. There are many factors which affect this, most notably riding style, that may or may not have to know with easy monikers like "road bike" or "utility bike". You should know these by now.

    I'd tell you what they are but it will probably not be heeded.

    BBB is right - people love to worry about stuff instead of experiencing it. There's no app, or blog, for the latter.



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    1. my utilitarian *moving average* is in the low 20s on my european city bike. i tried riding with a rack and panniers and absolutely hated the way the bike slid out while cornering. i use 15-30 liter backpacks and have no problem carrying a full case of wine home in my largest bag.

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  14. I must be an unusual case then. I prefer to distribute the weight equally on both sides when I haul stuff around in panniers. I can definitely feel the unequal weight if I don't do that ... Almost as if the bike is pulling to one side. I am short and slight, so maybe that has something to do with it ... Not sure.

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  15. Since years, I commute every day with an uneven load, work stuff in the morning and a few kgs of sports equipment in the evening. When I try to pay attention I can feel the asymmetry. When I stand up on the pedals it becomes more obvious, but it does not really affect handling on my bicycle with long chainstays in practice so I don't care. I also have done lightweight touring including big mountain passes with a single pannier only, without ever questioning this choice. After two years, the original aluminium rack broke, most likely due to the uneven load. I changed it for a (lighter!) Tubus steel rack and had no issues in the last three years since then. Every now and then I switch pannier side to keep the 'beausage' on rack and panniers symmetrical.

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  16. Few seen more sensitive to the nuances of bikes than you. I agree, it seems a non-issue. Today, after reading this, I conducted a little experiment. My daily ride to the grocery store, both panniers were empty….I took note of the ride up the hill and around the corners. Then loaded one side on the ride home. It was quite full and had to have been over twenty pounds (I've large panniers). Sure, I noticed it felt different when I was looking, but then again every load feels different. By all means, if one feels a need to distribute weight, do so. Mostly, I think it matters little.

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  17. Young Grad student came into the shop one day with a nice old Raleigh Sports 3 spd. Thing pulled to the left so badly you could hardly ride it. Checked everything, fork, frame, rack, looked for broken dropouts, everything. Nothing.

    Then the kids tells us he was gifted it from a retiring professor from the Art dept. We put a Reagan Bush sticker on the front fender and suddenly it was almost rideable but now pulled a little to the right, a small Mondale decal on the seat-tube brought it the rest of the way into trim and it was fine.
    Really, I'm serious, just like that.

    Spindizzy

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  18. My measured lopside was 37.5 lb in one Ortlieb Back Roller (IIRC, the load included a 6-pack of bottles and several bottles of wine), this on a 8/5/8 Rambouillet, on an 11 oz Fly rack. Sure the rear wagged a wee bit when first getting out of the saddle to stand, but the load quickly settled into the rhythm. While sitting it was hard to notice.

    On a noodly sports-tourer Raleigh Technium I once carried a stack of hardback library books higher than my knee, on one side, again on a Fly, 10 miles to the library and found the ride enjoyable.

    Lastly, if you want thin gauge, my '73 Motobecane fixie grocery bike, again with Fly, carried many a lopsided load (but I don't remember weights, alas) with no serious discomposure.

    This, for me, is one big advantage of rear loading over front. Try just 20 lb on one side of your Duo and see what happens.

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    1. Those Fly racks are excellent.

      I've carried bags of potatoes and similar on the left handlebar of my Seven on the last mile home after road rides. Steering feels heavy, but otherwise not too bad.

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  19. Great! Now I can stop arranging and rearranging the groceries in my panniers in an attempt to keep them balanced!
    I've only experienced changes in the handling when I have too much in either the front or back. Still trying to figure the optimal balance.

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  20. It's probably because I'm small (like 100 lb small) but I always feel imbalanced when I'm carring much weight in pannier bags.

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  21. I was a bit confused when I got a single (super cute) pannier tote for Christmas. Happy to report it works fine! Though I have found that I can take care of the imbalance issues when walking the bike and dismounting by just mounting the pannier on the right side - that helps a ton.

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    1. I've been using a rucksack strapped to my rack which is starting to annoy me, so was thinking about buying a pannier -- but I've not yet been in a situation where I would need two... So if I just get one, which side is better to put it on? Walking isn't an issue as I rarely ever walk the bike and it's got one of those centrally mounted kickstands on the hub of the rear wheel so it doesn't lean on the stand.

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  22. I'm inclined to think this is more a matter of upsetting one's delicate aesthetic sensibilities with asymmetry than any real imbalance, particularly with short urban trips. It's a little like men's dress shirts: why one chest pocket, and why only on the left side? What about the lefties among us?

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  23. Funny, in all my years of transportation cycling and, especially, carrying unbalanced loads in my panniers I've never once been asked questions about balance or potential frame damage. I mean maybe a hundred thousand miles in cities and towns on the west coast, east coast, and now the midwest. Is it because I'm not cute with a cool bike? Why would no one speak up out of concern for my safety or that of my bike's? Dunno….

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    1. I'm thinking

      (A) you look more badass than I do

      (B) you live in an area with a milder concentration of persons prone to approaching strangers with unsolicited advice

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    2. (C) Patterns of gender-specific-splaining send a lot of “advice" in your general direction.

      Though I did have some random guy remark on my cadence once on one of those Massbike summer rides. “Excuse me, I felt like mashing for a bit, I’ll return to 81rpm when I feel like it. It’s part of my bone mass therapy, twig-legs.” (no, I did not say that out loud)

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  24. I too have never really noticed an offset weight causing any problems when riding.

    The problem I have us that since I've ridden with a single pannier so much, one side is a much darker shade of color now.

    Maybe I should wash it.

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  25. I can't imagine that 10-25 lbs of weight differential could have all that much impact on a bicycle frame compared to the loads of rider weight and pedaling forces. Possibly it could affect a lightweight (flimsy) rack if you repeatedly hang a bag off one side only, but the rear triangle of a bicycle itself will handle the powerful assymetrical pull of the drivetrain for thousands and thousands of miles without a problem, I can't see how a laptop bag could bother it.
    I tend to put stuff in a front basket or on top of the rack myself, but that's because my giant sasquatch feet tend to give me a massive heel strike problem on all but the most spacious of setups.

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  26. I guess that my situation is fairly typical of the imbalanced loads we're discussing here, in that my groceries significantly outweigh my bicycle, and my body significantly outweighs my groceries. When this is the case it seems pretty intuitive that the imbalance should be much more noticeable when the bike is walked as opposed to ridden.

    It was previously mentioned that the imbalance is more noticeable when riding out of the saddle - unless you have unusually strong and stiff limbs, taking your butt off the seat essentially disconnects your body weight from the bike frame so far as lateral forces are concerned, so the imbalancing effect is again more noticeable, similar to when the bike is being walked.

    Please note I'm only talking about loads on the rear here, I've very little experience with loads on the handlebars/forks. Front loading of any significant weight seems pretty scary to me, particularly swinging grocery bags - when I see others riding with such I fear for their safety.

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  27. I'm a bit late to the game here, but since no one else mentioned it, I figure I would.

    I use an Arkel "Utility Basket" pannier bag. It's really decent for work commuting, as it's just a huge rectangular bag that is big enough for everything I need for work. I've got two of them, however since each one is large enough to completely hold a paper grocery sack, it's rather rare for me to need both for work, so I usually only bring one, only bringing the second if I need to run errands after work. It's a good bit faster not having the added wind resistance. Even with 20 lbs of whatever in just one pannier, I don't notice it while I ride. The bike leans slightly to the other side to balance, but I don't notice it much at all.

    Now, however, I ABSOLUTELY notice the unbalanced load when riding in snow and ice. If my bike is perfectly balanced, I can stay upright on slick surfaces pretty well, even without my studded tires (which I try to avoid using, they're soooo slow). If I have a load in a single pannier on just one side as soon as I hit a slick spot the rear wheel kicks out to the side. An unbalanced load makes it nearly impossible to ride in slick snow/ice. On dry pavement (or even just wet pavement) it's no issue at all, but on ice, forget it. I ride with both panniers in icy conditions to allow me to balance the load.

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