I have ridden time atacs in the past, and likes them. They were a step up from the crank bros i was using at the time.

However, are you sure you are using the right cleats? SH51 will only release when twisting out, SH56 will release if pulled hard enough.

I have never had fresh SH51 cleats pull out of old pedals. Perhaps I just haven't worn any pedals down enough.

Ignore if you are aware of this.