B-Fast RC Diff Ring Review Update:

So I had been running the stock rings and balls for a few races now and decided to open up the diff the see what was going on. I took everything apart and cleaned everything up. I took a close look at the stock rings for wear and could see the high and low spots on both rings. I was pretty surprised at the difference in wear marks on the rings! I was also examining how all the parts fit together and noticed some binding in the two small inner bearings (the ones in the diff gear). I found a thin Kyosho shim that fit between the bearings perfectly and prevents them from binding with each other (credit to local racer Bill Jones who mentioned this to me at last weekends race). I cleaned all the new parts with motor spray and then put the B-Fast Carbide diff balls in the diff gear and then the B-Fast rings on the outdrives with a couple of small dabs of CA on the outside to help secure them in place. I took the thrust washers and worked them with some 800 grit paper, cleaned them and installed Earls ceramic thrust bearings. The B Fast lube syringe is pretty sweet. Makes application precise, quick and easy. Re-assembled the whole gearbox and threw it back into the RB5SP. Fired up the car and ran a quick break in process on the diff and then made some final tweaks to get the tension right. Right off the bat I noticed I needed less tension on the diff to keep it from barking. Also, I really can't stop playing with the diff...lol...It is that smooth (it is sitting on the couch with me..haha). I have never had a diff this smooth and free..seriously, this is a nice kit. I would have never had guessed this kind of prep could make this much of a difference. I can't wait to try it out on the track (especially if it is a bit loose traction wise). I am hoping to head out next weekend to Glenwood Rc to try it out. Stay tuned for the results!


Stock rings. Hard to see uneven wear in the pic (crappy camera)


BFast ring ready to go in.


BFast Carbide diff balls


"Earl's" ceramic thrust bearing balls


Lube syringes


Accurate and easy application of lube and balls

I forgot to snap a few more pics of the build (including the little washer I was talking about). I will grab those when I tear it apart next time after some racing on them. Stay Tuned!

Edit: Speaking of Bill Jones. Ummmm I was checking out his RB5 and talking with him about his diff process as his car had THE absolute smoothest diff I have ever felt in my life. I will try to get some more pics and pick his brain on his diff building process, which is pretty extreme (talking slotting the outdrives to use blade inserts, sanding the diff rings, pinning the diff rings to the outdrives etc etc).