Frame Reinforcements & Gussets¶

Between 2011–2013, Surly introduced a small reinforcing tube (gusset) on the Pugsley’s seat-tube/top-tube junction. Below is everything we know about it:

Why the Gusset?¶

• Crack Reports on 2010 Frames
  • Multiple owners posted about small frame cracks “just behind the seat stay … right where the failures were on the 2010 models.”
  (Original: https://www.mtbr.com/threads/pugsley-frame-failure.828024/, Archived: https://web.archive.org/web/20230501000000/https://www.mtbr.com/threads/pugsley-frame-failure.828024/)

• Surly’s Solution
  • “2010 also saw a modest redesign of the Pugsley incorporating the seat tube reinforcing tube, seen on several new Surly designs…”
  (Original: https://fullspectrumcycling.com/surly-pugsley/, Archived: https://web.archive.org/web/20240501000000/https://fullspectrumcycling.com/surly-pugsley/)

What Exactly Changed¶

1. Seat-Tube Reinforcing Tube
2. A short, 19 mm OD chromoly tube is brazed between the seat tube and top tube, just above the weld where the seat stays meet the seat tube.

3. This “gusset” spreads weld stress over a larger area, reducing the chance of fatigue cracks.

4. Comparison Photos

5. Pre-2010 frame (no gusset) vs. 2011–2013 frame (with gusset)
   
   

6. Other Minor Weld/Tubing Tweaks

7. Head-tube and top-tube intersections retained the same straight 1 ⅛″ steerer and 69°–70° head-tube angle—no extra gussets were added there.
8. Chainstay curve, dropout width (135 mm), and all other geometry points remained identical.

How to Identify a Gusseted Frame¶

• Look at the seat-tube/top-tube junction from the non-drive side:
• If you see a small “helper tube” running parallel to the top tube for ~50 mm before joining the seat tube, that’s a reinforcement tube.

• If not, you have a 2005–2010 model (no gusset).

• Serial numbers for gusseted frames usually begin with “PUG11” or later, indicating 2011+ production.

Is It Worth Worrying About?¶

• By 2012, Surly had the gusset geometry dialed in—failures became very rare.
• If you own a 2010 frame, consider checking that exact weld area regularly.
• If you have a 2011+ frame, visually inspect once a year for any crack propagation around the gusset-to-seat-tube braze.

Sources & References
- Full-Spectrum Cycling (2011): “2010 also saw a modest redesign of the Pugsley incorporating the seat tube reinforcing tube….”
(Original: https://fullspectrumcycling.com/surly-pugsley/, Archived: https://web.archive.org/web/20240501000000/https://fullspectrumcycling.com/surly-pugsley/)
- MTBR Forum (2012): Owner reports of cracks “just behind the seat stay … where the failures were on the 2010 …”
(Original: https://www.mtbr.com/threads/pugsley-frame-failure.828024/, Archived: https://web.archive.org/web/20230501000000/https://www.mtbr.com/threads/pugsley-frame-failure.828024/)