My e50 as built by Paz with a gila kit has a hpi mini I put on correctly. I now how some play on the hpi mini rotor. I'm thinking it's the main bearing on that side. Hpi has a 280 gm add on. I contacted hpi about the part. I have two others on hobbits and wonder why this problem should be puch alone. So I asked for three. I looked on the puch shop and there is a add on weight but it was added several years ago and it's my belief that the hpi mini is a newer issue.