I'm rebuilding my steering head (WM20). Draganfly says there should be 40 ball bearings in total (I'm assuming 20 lower and 20 upper). However, it looks to me like the bottom race takes 21 balls. Does anyone know the right number? Thanks in advance.
Rule of thumb is to fill the race completely then remove 1 ball.
If you can put 21 in there and there is still some space then the race is worn past its servicable limit.
Also check you really have 1/4 balls.
A lot of places will try & flog you 4mm balls which are a touch smaller.
It's all good Trev. As an Aussie ex-pat living in Hawaii I can tell you that metric ball bearings are "special order". Everything is in inches...
I actually ordered a tapered roller bearing replacement but can't get the old races out. They are screwed-in. I'm gonna have to stay with the old system till I can afford the correct tool to extract them.
BTW - if your steering head ever feels a bit tight, loosen the front tank bolts first. The threads are open and if the bolts extend a bit too far, they pinch the yoke (insert hand-slap to head here).
In the meantime, I'll keep re-assembling as Hurricane Madeline bears down on my island.
Cas the head races are not screwed in. They are an interference fit. They have a thread on the inside to allow a plug to be screwed in to punch them out. Rob Nortier from this forum makes and sells the plug (he's in USA).
Or if you're going to throw them away anyway, do what I've done in the past and mig weld a short bar across the inside of the race to give you something to punch against. The heat from the weld will make them even easier to remove.
Been there with too long tank bolts and got the scars on my steering stem to prove it. The steering felt like a 'threpenny bit' Ron
re cheap balls - I guess chinese balls will always be a bit smaller than imperial ones ;-) ... But 4mm is a huge difference. The closest metric size would be 6mm. If one were to use 20 x 4mm balls in a WM20 race, there would be 40mm spare space or 1 5/8" That seems difficult to miss.
I can vouch for Trevor's method of removing difficult races. I took two out of a JCB that were impossible to move. The ring of weld as it cools contracts the race.
"Arc Welders, so much more than just a cutting torch!"
