Answer
Apr 13, 2026 - 07:55 AM
Yes, it should still fit with 5/8" insulation over the wheel well.
The S&B 34‑gallon ProMaster wheel‑well tank is 14" wide overall and is designed to bridge over the factory wheel tub with some clearance to spare. Adding 5/8" insulation on the outside of the wheel tub eats into that clearance but doesn’t exceed the built‑in allowance, so you won’t max out the 14" width.
As long as your insulation stays close to that 5/8" thickness and you don’t add additional furring or plywood over it, the tank will still drop over the wheel well and strap down normally.
