Why we broke the rules to get this customer up the steepest climbs by Tuesday!

The Impossible Deadline. A regular customer dropped off his Trek with a shattered shifter on Thursday and a flight to catch on Tuesday. The destination? Somewhere with very steep hills. The problem? 11-speed replacement parts are scarce and expensive, and his BB90 bottom bracket was literally falling out of the frame. In this video, we navigate the parts bin crisis, explain why we chose a full 12-speed Shimano upgrade over a "standard" repair, and perform a "lethal" bodge by exceeding the rear derailleur's max capacity to give him the climbing gears he needs. We dive into: Trek BB90 Repairs: Using the Token screw-together solution for worn carbon shells. Mechanical Sympathy: Why cross-chaining on this setup could be a "mechanical catastrophe." Derailleur Capacity: The math behind the 39-tooth limit and why we ignored it. Crank Length: Swapping 172.5mm for 160mm for better ergonomics. Warning: This setup requires a high level of mechanical awareness. Don't try this at home unless you're prepared to stay out of the "big-big" combination! Video Chapters 00:00 The "Tuesday" Deadline Challenge 00:44 The 11-Speed Parts Crisis 01:28 Chain Suck & Worn Drivetrains 02:21 The Cost of Sourcing Rare Parts 03:14 The 12-Speed Upgrade Proposal 03:58 Trek BB90: The Carbon Shell Nightmare 05:41 Using Feeler Gauges to Check Frame Wear 07:15 The Token "Screw-Together" Solution 08:18 Frame Protection & Cleaning 09:09 BB Installation & Assembly Grease 11:09 Why we chose 160mm Cranks 11:50 The "Lethal" Chain Sizing Risk 13:55 Setting Chain Length for Extreme Ratios 15:54 Derailleur Capacity Math Explained 18:36 4 Ways to Get Lower Gearing 19:32 The Final Bill & Mission Success