Here are some of the largest flat mtb platform pedals:
- Crank Brothers Large Stamp Pedals (Width: 114mm x Length: 111mm footprint) Weight 405 gram, recommended for shoe sizes 10-15 (US Men's)
- VP Components Harrier Pedal - Widest flat pedal? (Platform size: 120mm wide and 110mm long) Weight: 362 grams, Thickness: 12mm
- Catalyst Pedal - Longest flat pedal (Length: 128mm x 95mm platform, 16mm thickness) Weight: 505 grams
I own all 3 of these pedals, and would recommend the Crank Brothers Large Stamp pedal as the best all around large mtb flat pedal.
The new version of VP Harrier Pedal started making loud creaking noises after a month or so of riding on them, but do like the feel of the pedal.
The Catalyst pedal is interesting to ride at first, but it's heavy, prone to pedal strikes (especially if you use the taller pins) and just too large for technical trail riding (roots and rocks) and it's not a good pedal if you're going to be doing any sort of dirt jumping (IMHO) because you can't curl your feet on the pedal, so it's easier to loose your footing in the air... It might be a comfortable winter fat bike pedal though when wearing larger boots, as the pedal does support the entire foot.