I recently filmed the track-installation process for a Liebherr PR 776 crawler bulldozer at the Liebherr factory in Telfs (Austria). During assembly, the tracks are not pre-mounted to the undercarriage before attaching the upper structure. Instead, the tracks are installed as a separate stage, where a full rolled track chain is unwound under tension and wrapped around the final drives and rollers.
Here is a short video showing the exact process: 👉 https://youtu.be/7aNdsUDCfmU
On the other hand, many excavators are assembled differently:
The tracks are installed directly onto the lower frame at the beginning
Then the complete upper structure (“the house”) is lifted and bolted to the undercarriage — the so-called “wedding”
My question: What engineering or manufacturing reasons explain why bulldozers, especially heavy units like the PR 776, use this separate track-installation method instead of the excavator-style pre-mounted approach?
Possible factors I’m wondering about:
Weight distribution or frame geometry
Tensioning requirements of bulldozer tracks
Differences in undercarriage design (e.g., sprocket position, roller layout)
Ergonomics and safety of lifting the full assembly
Production-line constraints
Component access for hydraulics or final drive assembly
I’d really appreciate a detailed engineering explanation. Thanks in advance!
