I have a Topeak Super Tourist DX rack and an MTX TrunkBag DX bag, which fit together using Topeak's QuickTrack system - a dovetailed plastic foot on the bag slides into a metal channel on the rack.

Both are several years old. Recently, the combination has developed a wobble, where the bag seems to be able to move from side to side in the rack. The bag doesn't fall off, but the noise is annoying!

What causes this? Is the plastic foot worn, or is the metal channel bent?

Is there a cure for it, apart from replacing one or both parts?

  • Re Is the plastic foot worn, or is the metal channel bent? Unless this is a common issue that many people in the BSE community have experienced, there no way for us to answer that. Why don't you inspect the bag and rack yourself to see what's causing the bag to not fit properly into the rack? Feb 21, 2020 at 19:20
  • 1
    Shock cord!!!!! Feb 21, 2020 at 21:37
  • @ArgentiApparatus is correct. Have you tried searching for spare-parts via Topeak ? They list 292 different service kits across their entire product range. topeak.com/global/en/products/service-kit The worn item is possibly a replaceable part, and any decent LBS can order it in for you.
    – Criggie
    Feb 21, 2020 at 23:29
  • Otherwise, please add photos and good measurements of the different mating areas.
    – Criggie
    Feb 21, 2020 at 23:30

1 Answer 1


As an interim answer, it sounds like the plastic track has been wallered out and now has play between it and the metal track.

Stock photo
Topeak UNI Super Tourist DX Disc Carrier stock photo showing rail in the middle

Stock photo
Topeak MTX Trunk Dry Bag stock photo showing underside.

First guess is that the grey plastic foot has worn through insertion/removal over time. I doubt the metal has worn, but it may have unfolded a little.

You need to look at your bike and see which is the cause.

Your options are:

  1. Check that the foot is not wobbling on the bag - as ChrisH points out they're only rivetted together, so it may be sloppy there. Drill out the old rivets and install some small bolts with washers, and nyloc nuts to stop them coming apart.
  2. Pack the gap between plastic and metal using a strip of additional plastic. I hear sugru is the bee's knees for this kind of repair but it probably wears even faster than the original. Or you could use a long thin piece of brass or aluminium, which would wear faster than the steel, but may need one on each side. This might be called a "Gib" in the machining world.
  3. If the metal runners are bent outward, you may be able to bent them back in with pliers or a vise or a big clamp. Risk is snapping the steel, or potentially weakening it. I doubt this part is available as a service item.
  4. Replace the plastic foot completely. I do not see this as a service item to purchase, which is somewhat surprising.
    You might try to 3D Print a replacement, after taking careful measurements of your existing one and of the rack track. Or if you lean more to woodworking, a hardwood rail with the right dimensions could bolt on in place of the worn plastic one. You could mill the new foot out of aluminium too, depending on what access you have to tools.
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    A couple of minor things - I'm fairly sure the track is aluminium (not steel), and the plastic is riveted to the bag under the stitching, which is probably why they don't regard it as replaceable
    – Chris H
    Feb 22, 2020 at 14:18
  • @ChrisH okay good spotting. Anything's replaceable given the right tools, which would be a twist drill for removing rivets. I'd use small bolts to reassemble.
    – Criggie
    Feb 23, 2020 at 0:08
  • Yes, I've got one but I haven't had the chance to look at it yet
    – Chris H
    Feb 23, 2020 at 8:49

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