RUPES BigFoot LHR21 Mark III Review: Built for Hoods and Roofs
Our Verdict
The fastest way to correct large, flat panels without a rotary. A 21 mm orbit on a 6-inch plate covers a truck hood in the time a 15 mm machine does half of it, and the Mark III motor keeps the pad turning under pressure where older BigFoots stalled. It's too big for bumpers and pillars, which is why it's the second RUPES people buy, not the first.
The LHR21 is the big BigFoot: a 21 mm orbit and a 6-inch backing plate, built to cover area. On a hood, a roof, a truck door or a van side it corrects faster than any other dual-action machine, because every rotation of the pad moves it nearly an inch across the paint. The Mark III is the version that fixed the original's one weakness — stalling under pressure — with a stronger motor and electronic speed control that holds RPM when you lean on it.
In use
Pair it with a 6-inch microfiber or foam cutting pad and a compound like M105 or Turtle Wax 1 & Done and a full-size hood is a single section. The progressive trigger, speed dial and rubber grips are the same as the smaller BigFoots, and vibration is remarkably low for a machine this size. Fatigue over a long day comes from the weight, not the buzz.
Where it struggles is geometry. A 6-inch pad on a 21 mm orbit needs flat, open paint. On a curved bumper, an A-pillar or the area around a door handle, the pad edge lifts and the throw works against you. Every LHR21 owner also owns a LHR15 or a LHR75E Mini for the rest of the car.
Mark III versus Mark V
RUPES has since released a Mark V LHR21 with the composite gears and quieter running of the LHR15 Mark V. The Mark III remains the version with years of professional use behind it and a large body of owner experience, and it is often available at a better price. The correction capability is the same.
Who should buy it
Detailers who work trucks, SUVs and vans, and anyone who already owns a 15 mm machine and wants to cut hood-and-roof time in half. It is not a first polisher — see our DA polisher guide for those — and it is not a solo polisher. It is the specialist that makes the big panels quick.
Pros
- Fastest correction on large, flat panels
- Mark III motor resists stalling under load
- Smooth and low-vibration for all-day work
- Mature pad and accessory ecosystem
Cons
- Too large for bumpers, pillars and curves
- Heaviest machine in our lineup
- Needs a smaller polisher to finish a car