Problem: Pedal Washers and K1 Cranks

I got some K1 160mm cranks for my muni, was told I had to use the pedal washers, however, they don’t seem to keep the pedals tight and when I cranked the pedals down really tight, the washers oblonged and ultimately shredded.

So now I’m running them without washers, which keeps the pedals tight, but I was just told that the inserts will tear our of the cranks without washers :astonished:

So, should I worry? Is there a better/more durable pedal washer?

I think the washer is only needed one the first batches.
But if you want to use a washer, just use some of your DIY shop, works as good as the k1 (if not beter ;))