I now have 5300+ miles over three years on my Agattu B8 with no problems. But I have a Bosch drive train. Impulse has a bad reputation and I don't think Kalkhoff uses it any more. But Kalkhoff also doesn't market in the U.S. any more so I probably won't buy Kalkhoff again, either.Don’t buy a kalkhoff with an impulse motor you’ll be sadly disappointed as I was, I’ll never buy Kalkhoff again, go for Bafang much better