Ahhhh.. In 125lbs with gear , 5'3" maybe and I can plant my left feet fine when at a stop light. He should just practice and ride more. You'll get the hang.
Only time when I need to feet down is to reverse walk the bike, but I don't do that. I just get off and push it
Same here, 5'3", a little under 150lbs without gear. I can just barely tip-toe both feet with an unmodified bike. I can get one foot flat sliding to the edge of the seat a little (not that much). Here are some things he can do:
- Stick a heel cup in a boot.
- Add a rubber heel on the outside of the boot (nothing extreme, just a little). Doing these first 2 things gives 1 flat foot without stretching.
- Get suspension set for his weight.
- Shave seat.
- Lower it.
Like Nuttynu said, get off to reverse it, it's faster and takes away the risk of a stupid drop. I can push mine backwards a little, just need to be sure of the terrain first.
The idea of having 2 feet flat is an idea taller riders seem to have and think is a necessity, but it isn't. Even on a lower bike I had (CB400), I almost never put 2 feet down. I like keeping my right foot on the peg to light up the brake if someone's approaching from behind. In any case, it's useful to be able do this starting on a hill. I can balance the bike no problem with 1 foot down and no hands sitting in neutral stopped at a light. Your buddy needs experience and confidence more than a mod to the bike, he'll get it in time.