This may go down as one of my dumbest questions ever, but I googled it and didn't find any answers... We all know to check hub center bore when selecting wheels, since most car manufacturers stick to their unique size. But, why didn't they arrive at a standardized size? Are they different simply because they wanted to be different, and never felt compelled to change?

It seems like there had to have been a reason early on, otherwise why make it harder on the aftermarket wheel industry just because? It doesn't seem to have any performance related explanation (strength and weight), as one manufacturer will have the same hub size across their line of econoboxes and sports cars. It ought to be a very simple thing to standardize, and I can't come up with any good reasons not to.

The question has been bugging me this week, having just picked up some hub rings to adapt a Nissan spare to the Toyota hub.

 

just a guess but maybe the hub size has to do with the weight, power, balance, and other factors of the car. the hub bore is related to the axle diameter i believe and it would be a waste to have an axle larger than needed on a car and dangerous to have one smaller than needed! maybe that's the reason they're all over the map.

so if that's right, car mfrs only want to use as much steel as needed to manage costs, and changing the hub bore on the factory rims is a small deal for them. they don't give a crap about aftermarket rims.

 

Why wouldn't they just use the smallest size that's proven to hold that power, then? Why does Mazda use 54.1mm, Toyota 60.1mm, and Nissan 66.1mm (I think those are right, off the top of my head) across a wide range of vehicles with widely varying weight and power output? It seems like they each just chose a size that has nothing to do with the vehicles themselves. Obviously, they stick to the size that everything is tooled for, but why choose those dissimilar sizes in the first place?

 

The same reason Canon lense doesn't fit on Nikkon lense they don't want other manufactures wheel on their own car.

 

That makes a decent amount of sense, I suppose. I'm not quite sure I buy the camera analogy, though. Lenses are an accessory for cameras, so it makes sense to tie someone to the brand. Wheels are rarely replaced by the average consumer, however, and very rarely with OEMs. Maybe that was different back in the wooden wheel era... When did different hub sizes come about?

It just doesn't seem like there's any financial or branding incentive on the part of the car manufacturers to do so. Wheel replacement has gotta be an infinitesimally small effect on the bottom line for them, and pretty much anyone that puts a different make of OEM rims on gets rid of the center caps, so no conflicting branding.