Here is a picture of what happened to my drivers side tire on my 20 loop. The foam filled tire has been chewed up. I dont think it was properly foam filled. It looks like the tire guides eat the tire on maybe some tight turns? Anyway I have oredered a set of new fron rims and "fork lift" soild tires from BOGGIE as per his recommendations. I can see how the fork lift tires would be a better solution on the front. I will replace both front tires! In the mean time I will through one of my spares on.