Scooterotica

holty wrote:af rayspeed are working on a new type rear bearing, it a double bearing so much stronger

ming wrote:I'm currently working on a mate's engine which I originally built 3 years ago with an MB rear hub bearing. Not long after that he complained that he was losing gearbox oil, although intermittently. I started suspecting a bad drive side seal, but upon hearing him also complain of a non-functioning rear brake, we took the hub off and noticed the brake shoes completely soiled with oil. I figured we'd found the culprit--a failed rear hub seal, but upon removal discovered the bearing had lost both its plastic cage and half of the balls. There were bits of plastic all over the xmas tree gear cluster. This, after barely 3 years and 3000 miles. Motto: plastic does not belong in a bearing, let alone such a critical one as the rear hub. Never again. I shudder to think how close he came to disaster and injury. This is why it pays to change the gear oil frequently and always look carefully for any bits that come out....

(Which reminds me, I need a new chain for my DL, because guess what bits fell out when I changed the oil....)

hendy wrote:

holty wrote:af rayspeed are working on a new type rear bearing, it a double bearing so much stronger

I'm not exactly sure what you mean, but as a rule of thumb, three bearings on one shaft is a no-no. It's close to impossible to align them perfectly and if the shaft that they all sit on is short and/or stiff then it can apply enormous side loads on the bearings; particularly the middle one.

I've seen seriously strong bearing housings crack due to this.

holty wrote: many years ago i used to be into classic minis, and i had a well tuned engine in my last one, and it kept breaking gearboxes, it would crack the housing that held the main shaft, that was a doublebearing, it has one cage on the out side but two sets of balls and races on the inside, so was one bearing but twice as strong, i think its the same design that rayspeed are develpoing at the moment.