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On a recent 3 week trip I used a handlebar bag (together with two back bags) to carry the stuff I needed. In the handlebar bag I carried a reflex camera, my phone, a power bank and some candy.

While my bike normally feels really stable, the first few days with the handlebar bag were a nightmare: the handlebar constantly felt really wobbly, to the point I had to check it was not loose. Then I got used to the feeling, but still could not completely trust the bike.

Can the handlebar bag cause such behaviour, and how can I mitigate it?

Edit: I had a picture of the handlebar bag to give an idea of the dimension. About the mounting, the bag itself is firmly held on the handlebar, and also the content did not have much clearance to move inside, maybe less than a centimeter. The reflex bag basically left only the space for the smartphone.

enter image description here

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    A handlebar bag should only be used for relatively light items. And regardless of what it contains it needs to be tightly strapped, so it doesn't flop around.
    – Daniel R Hicks
    May 9, 2017 at 11:57
  • Are you sure the rear bags were not a factor. Did you try front with no rear bags.
    – paparazzo
    May 9, 2017 at 12:56
  • @Paparazzi, I have done about 50 km with only the front one, but it was later in the trip when I was already used to the feeling.
    – L.Dutch
    May 9, 2017 at 14:45
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    That bag is a very long way in front - probably more suitable to drop bars where your hands (on the hood) are about in line with the middle of the bag. Try swinging it down more so its hanging and see if handling improves.
    – Criggie ♦
    May 9, 2017 at 20:02
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    If that's a Rixen & Kaul KLICKfix mount - which is what it looks like - then I think it's mounted wrongly. This picture from their site shows the stabilizing cable (which they've left loose) the other way up to your photo. That's just to stop the bag rotating forward, so it may not help, but is still worth fixing.
    – Useless
    May 10, 2017 at 18:47

4 Answers 4

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Yes, the bag can cause the instability. The physics is quite simple.

Ordinarily, a bike is self-stabilizing. If you turn the handlebars to the left, you steer to the left and the bike leans to the left. However, the turning gives a centrifugal force to the right, which causes the bike to want to lean to the right which, in turn, straightens it out.

With a bag on the handlebars, things change. With the bike perfectly upright, the weight of the bag acts completely downwards and does nothing to turn the handlebars. However, as the bike leans to the left, the bag can lower itself by turning the handlebars further to the left. If the bag is heavy enough, this effect will overcome the self-righting stability of the bike and now you have a system that responds to a slight turn to the left by trying to turn more sharply (positive feedback) rather than the usual situation of responding to a slight turn to the left by trying to go straight again (negative feedback). This is the instability that you felt while riding.

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  • Definitely a big part, yes. The shifting of the weight when the bag does not act like a solid piece (as the rest of the front of the bike does, mostly) adds a squishy feeling that also tends to reduce "trust".
    – Deleted User
    May 10, 2017 at 17:50
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That's fairly normal behavior. You point out that you got used to it, but couldn't "trust the bike". It's a very similar scenario to moving to a new bike with much different geometry and not trusting the bike, your body and learned muscle memory needs time to adjust. Weight strapped to the front of your handlebars tends to do this, especially when it wobbles a bit or is free to move.

I've done several races requiring a winter sleep system where I've ended up having to strap 10+ pounds (4.5+ kg) of -20°F (-29°C) sleeping bag, mat, and bivy to the front of my bike. The first several hours riding (if I haven't practiced with it) are the worst, but eventually your body adapts to the feeling. It definitely affects the handling on snow and even after my body gets used to the weight, it takes a bit before finer handling begins to seem normal.

There are really only two things you can do, pack as light as possible (if you NEED to pack on your handlebars) and make sure the load is WELL secured so that the weight doesn't have a sloppy feeling to it. When securing the load make sure you don't interfere with your cables or damage them. Simply mashing everything against your cables will/can cause shifting or braking problems.

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    In my experience it is specifically the wobbling of the bag rather than the weight of the bag that causes the feeling of instability.
    – Penguino
    May 9, 2017 at 21:30
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Yes. Don't use a handlebar bag if it affects your bike's handling that badly.

Perhaps your frame is just not suitable for a handlebar bag - normally a fork with a lot of trail (ie a stable touring style fork) would be best.

If your bike is a "twitchy" or "responsive" or sporty bike, then the bag will put weight on the wrong side and essentially act like the fork is reversed.

So you should only put light stuff in your handlebar bag. Clothes would be about it.

Instead you might find a rear rack works better for you, or possibly front panniers. They strap on low-down and put their weight evenly over the fork rather than "in front" of the steerer.

Rear panniers or a frame bag might work for you. If you have a lot of stuff, a load bike or even a cargo trailer might be a better solution.

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    A note on front panniers: if unevenly loaded they're worse for handling than handlebar bags. I occasionally have to ride a few miles with a single front pannier of a few kg and it's quite "interesting". (+1)
    – Chris H
    May 9, 2017 at 11:44
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    Clothes are heavy. At most a very light jacket or something of that nature. And front panniers are a problem if the load is not well secured so that it doesn't flop around.
    – Daniel R Hicks
    May 9, 2017 at 11:59
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    @ChrisH; again, that comes down to bike geometry. I've put a single front pannier (i.e. left side only, nothing on the right) on my very stable touring bike and barely noticed a difference. Long trail on that one.
    – Jason
    May 9, 2017 at 23:40
  • Could you explain what you mean by "trail" in opposition to twitchy/responsive?
    – Nobody
    May 9, 2017 at 23:48
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    @Jason that's reasonable. I'm shopping for a tourer at the moment -- I wonder how that will handle.
    – Chris H
    May 10, 2017 at 5:49
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Other options (given that you already have rear panniers) include:

  • top tube bags (for phone, power pack and snacks but not the camera).
  • a trunk bag (on top of the rear rack)
  • rearranging so that the heavy stuff is in the panniers
  • a backpack. That's what I do carrying my SLR because I have a camera backpack.

My handlebar bag recommends something like 2kg. Above about 3 it's twitchy but OK on my hybrid.

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