Topeak Backloader Wishbone review – seatpack anti-sway stabilizer

Topeak’s Backloader Wishbone is designed to stop seat pack flop for boisterous bikepackers but it’s not without it’s issues

Topeak Anti Sway Stabilizer on bike
(Image: © GuyKesTV)

Bike Perfect Verdict

If your bag fits then this is potentially a useful seat pack stabilizer and bottle mount propagator. Lowered fit won’t work with all bikes though and our sample had real clunk issues.


  • +

    Reduces sideways seatpack swing

  • +

    Adds two bottle cage mounts


  • -

    Our sample clunked badly when it moved

  • -

    Drops seatpack significantly lower

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    Slotted guides only works with some bags

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    Saddle rail overload concerns

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    Only works with round saddle rails

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If you don’t like the way a loaded bikepacking seatpack can sway and swing when pedaling out of the saddle, Topeak’s epically titled Backloader Wishbone anti-sway stabilizer looks like a useful solution to the problem. The bolted build was slack enough to cause very irritating clunk though, while the lower bag position and saddle rail clamping are other potential problems.

Topeak's Anti Sway Stabilizer on a metal floor

Multi part design adds weight and wobble but doesn't add any adjustability  (Image credit: GuyKesTV)


As the mouthful of name suggests the ‘Anti Sway’ uses a wishbone design formed from two 'S' bent arms. These have flat sided ends that slide and bolt into a cast alloy clamp, that in turn slides and bolts into a forged alloy arm with a slim serrated saddle rail clamp at the end. The far end of the wishbones also point vertically down with plastic guides for bag straps on the inside and bottle cage mount bolts on the outside. 

Topeak Anti Sway Stabilizer with bag

Using the Anti Sway drops seatpacks lower which can create tire clearance issues but it adds two bottle mounts (Image credit: GuyKesTV)


Once you’ve bolted it together you slide the narrow clamp onto the horizontal, parallel section of your saddle rails (it only works with round ones) which can be tight on space already. Even though the clamp is upturned, the way the frame takes up space still drops overall bag height by several centimeters – which can cause tire clearance issues on smaller frames/shorter seatposts. While the slotted strap guides on the vertical arms work well with Topeak’s own saddle pack, they didn’t really work with the Ortlieb, Alpkit or Apidura bags I tried.

The biggest issue though is that the flat sided sections of the arms are loose inside the saddle clamp arm. The fastening bolts are just screwed into the far end so there’s no clamping effect either. That means while the wishbone does reduce bag sway out of the saddle, you get an obvious clunk through the whole bike with every swing of the bike one way or the other. Not only is this really irritating, but from experience it’s the kind of clunk that’ll rapidly propagate into loose bolts or other issues – although to be fair the saddle clamp bolts are Nylocked for security. 

Given the battering bikepacking saddles already have to put up with, adding a thin, ridged clamp onto the rails and then potentially sticking a pair of bottles cantilevered out at 165mm to the situation seems to be asking for trouble over time.  

Topeak Anti Sway Stabilizer clamp detail

The saddle clamp is where the irritating clunk and potential rail stress come from  (Image credit: GuyKesTV)


The basic ‘anti sway’ concept of the Backloader Wishbone stabilizer is a good one and on a basic level it does the job. The practical detailing is way below Topeak’s normally excellent standards and my concerns about the narrow saddle clamp combined with the lowered bag height and irritating clunk means I’m struggling to recommend it.

Tech specs: Topeak Backloader Wishbone

  • Price: £34.99 / €34.95 
  • Weight: 190g 
Guy Kesteven

Guy Kesteven has been working on Bike Perfect since its launch in 2019. He started writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear. He’s also penned a handful of bike-related books and he reviews MTBs over on YouTube.

Current rides: Cervelo ZFS-5, Specialized Chisel, custom Nicolai enduro tandem, Landescape/Swallow custom gravel tandem

Height: 180cm

Weight: 69kg