Hi, what size are B4 ball stud?

[mattlynch]

Hi , could someone tell me the diameter in metric of the ball part of the ball studs used on the B4 buggy? , i am asking because i would like to use the rpm ball cups which only seam to be made for the B4/T4 ,, with m3 threaded ball studs on my all metric X-pro, thanks for any help folks.

[Big G]

I don't think the plastic is cut to any thread when brand new. If they are for the B4 the cup will fit no problem. If the ball studs themselves are M3 thread ideally you'd want to fit them into new hubs/mounts so it cuts in that thread instead of the 4-40 standard.

[mattlynch]

Originally Posted by Big G

I don't think the plastic is cut to any thread when brand new. If they are for the B4 the cup will fit no problem. If the ball studs themselves are M3 thread ideally you'd want to fit them into new hubs/mounts so it cuts in that thread instead of the 4-40 standard.

thanks for the reply, still need the ball diameter as its just the RPM ball cups i want to use on an all metric X-Pro chassis, i could use 4-40 ball studs from the b4 but dont want to buy all new hubs ,uprights, bulkheads ,ackerman plate, servo saver. cheers again

[sosidge]

Originally Posted by mattlynch

thanks for the reply, still need the ball diameter as its just the RPM ball cups i want to use on an all metric X-Pro chassis, i could use 4-40 ball studs from the b4 but dont want to buy all new hubs ,uprights, bulkheads ,ackerman plate, servo saver. cheers again

Because I'm such a nice guy, I just measured one for you.

4.28mm (as near as dammit 4.3mm)

I don't know what size the X-Pro uses - probably either 4.8mm or 4.3mm. If 4.3mm then US-style cups should fit, if 4.8mm then Tamiya or Kyosho cups should fit. I wouldn't be surprised if the Kyosho ones are the ones to go for since the X-Pro is basically a copy of an RB5.