If anybody else can find a 30% hill where they live (not 30% from Strava, but with a sign that says 30% or 1 in 3 or confirmed by Google earth), go and try it on your legal bike and tell us how easy it is. I have two where I live that peak at about 30% for a short distance. I have 500w geared motors and 500w crank-drives, both running at 30 amps, which is double what legal bikes have. They all struggle up these slopes. Please pass on your experiences.
Eddie, you should check those slopes on Google Earth before spouting off like that.
Forgive me if I'm wrong, but I think you guys are comparing apples and oranges.
Dave - (100kg?, tired knees, cycling to keep fit, but like most of us could be fitter)
Eddie - (70kg?, no knee issues, super fit to the point of nutty.)
Different heights, riding styles and weights.
If the rider is struggling with 30%, there is only so much the bike can do to assist. More rider effort stresses the bike less, as does a lower rider weight.
I have to say I think you are BOTH right, but at the end of the day as it depends on the rider more, I think Dave is more right and Eddie is just reaping the benefits of being a very light, very fit, very good mountain biker!