Will Changing From Idler Hub to Hub/Drum Change Wheel Offset

Question:

Ive got a 3500lb axle with hubs. No brakes. The square backing plate is there, so Im planning to add brakes, probably with your 84546UC3-EZ drum/hub, and the complimentary 10x2.25 electric brakes. My question relates to the positioning of the trailer wheels after I change my hub for a drum/hub. Am I likely to find the wheel in exactly the same spot width-wise where it is now? Ive only got about 1/2 of clearance between the trailer frame and the inner sidewall of the tire, so if drums/hubs are unpredictable in terms of width/offset, that might be a nasty surprise. Im hoping that my concern is unfounded, and this is a problem that was solved/standardized many decades ago... Thoughts?

asked by: Chris

Expert Reply:

I ran out to the warehouse and pulled one of the # 84546UC3-EZ hub/drums, which I compared with a typical idler hub with 5 on 4-1/2 inch bolt pattern for a 3500 lb axle. I found that with both hubs, the distance from the rear seal surface to the front face of the hub where the wheel would ride is 2-1/2 inches. Since I do not know which hub you are currently using, I checked a few other idler hubs, and found that the 2-1/2 inch distance or thickness was the same.

Long story short, your tire should ride in exactly the same spot it is now.

The # 84546UC3-EZ uses a L68149 inner bearing and a L44649 outer bearing. You will need to check your existing bearings and make sure the reference numbers match.

expert reply by: Mike L