Can anyone tell me if the wheel PCD of the 6 hub bolt holes are the same for the (09/10) 5 1/2" and 6"Diameter Hubs as fitted to the later years.
I would imagine that the 6"Diameter Hubs had a larger PCD than the 5.5"Daimeter?? If so, what is the smaller PCD??
Thanks. Alan in Western Australia
What is PCD?
Pitch Circle Diameter?
Yes, pitch circle diameter. I hadn't heard the term until recently when I was looking for a trailer spare. Its a way of determining the bolt pattern by measuring the distance between adjacent bolts.
Alan, I can't tell you a measurement right now, but the PCD for 5 1/2" hubs is smaller than the PCD for 6" hubs. You would have to re-drill the hub bolt holes to put a later hub in a 1909-10 wheel, or vice versa.
You can tell a 1909-10 wheel with a 6" hub in it because the outer diameter of the hub and flange covers the joint between the spoke shoulders. In other words, the distance from the rim to the spoke shoulder is longer on a 1909-10 wheel than on a 1911 + wheel.
Pitch Circle Diameter sounds like gear terminology. Usually you speak of bolt hole patterns in terms of B.C., Bolt Circle. But maybe the verbiage is different in Australia.
Thank heavens you guys cleared up what PCD is. I thought it stood for Perth Cop in Drag!
The 5 1/2" hub has 5/16 bolts and they 4 1/2" between centers.
The 5 1/2" hub has 5/16" bolts and they are 4 1/2" between centers.
PCD is widely used in the UK, and in Canada too. Machinists here in Canada still use both terms, B.C. and PCD....just like using inches AND millimeters