Yet another reply to your hard riding- I have a similar problem on the Tandem. Full offroad Tandem with an all up weight of 400lbs. It is ridden aggressively and in the early days- it was a problem to try and keep the thing intact on a ride. Luckily the frame is solid but we were bending Bars just by showing it a fast stretch of track. Wheels going out of true on every ride and suspension forks were a pain just to stop bottoming out at the slightest bump. Luckily with MTB's there are Heavy duty parts made for those that leave their brain at home before they ride (Downhillers in the main). Problem is that there are heavy duty and there are heavy- do not be confused between the two. Bars went to Full downhill for both the pilot and stoker and it was not untill the pilot got 1/4 thick walled bars that he stopped bending them. Front forks went to full downhill with extra heavyweight springs and the wheels- Well only the strongest Mavic downhill rim and the toughest Hope BigUn hubs managed to stop the wheels from whimpering. Brakes had to go to Hope Mono M4 with 200 mm discs. This thing is heavy but the fun element of 50mph downhill offroad is tremendous. The joy of pedalling a 55 lb bike up hills is not so great but still gives one a sense of achievement.

So Look at the Freeride bikes and Parts for the MTB- but how you are going to keep a road bike together- Hope you have a big wallet.



And on the OP- I have not experienced the problem of feet hitting the frame- but this is because I have always ridden with toein on the feet. Keeps the heels away from the stays and this is assisted by setting the clipless pedals up to keep the heels out.