I rode with a QR for a short time with a 70 gear inch (44x17) set up. I had to go up a short, maybe 6ft. section of sidewalk once to get into the cul-de-sac from the main street. So I crossed the street, went up over the curb, and started the about 45degree climb from a dead stop, as I got to the top my QR rear slipped causing me to scrape my ankle pretty good on the crank and land on the top tube. I got rid of my QR shortly thereafter. Never had any problem with my front QR. Always paranoid about sticky fingered passers-by though. ymmv.