Hubcentric wheels on Ultralite

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Maybe I should have posted this earlier, but with a bunch of small kids and a business to run, and a 2000 mile family move to Austin, I have haven't been lurking around much.

 

Maybe there is a hub & wheel expert out there that will tell me that I'm wrong, but I would say that there is never a reason for "hub-centric" fitting of wheels on hubs.

 

I'm a life long car nut, former FSAE team member, mechanical engineer, and I teach "Geometric Dimensioning and Tolerancing" (GD&T) in industry, which is all about parts fitting together. With hub-centric, all I can see is a ring fighting the lugs for centering, with neither winning in an absolute sense.

 

The plastic rings for an assembly aid make sense though.

 

Best Regards,

Dean

 

thanks dean.

 

there's a lot of noise on the web about the centric rings stress shielding the lugs, but when i started to think about it, that didn't really make sense as the wheel is very tightly clamped to the hub. intuitively it seems like it would take a lot more force than would normally be encountered driving to break through static friction once the lugs are torqued down. the rings do make mounting the wheels quicker and easier though.

 

and welcome to texas! i live in houston myself. i hope you're enjoying our fantastic summer weather!

[DeanD3W]

Scott,

Thanks for the welcome to Texas. My kids are having the best Summer ever and their upcoming Fall, Winter and Spring will be better yet I believe.

 

Regarding wheel mounting, it sounds like we agree... The only way centering rings could shield the lugs from stress is if they were fit so closely to the hubs that there was no clearance at all, which is really a press-fit and then the wheels would need to be similarly press-fit onto the rings. Then there's the point you're making about static friction between the hub and wheel face preventing any movement once the lugs have been tightened and located everything with their tapered mating faces.

 

Center-lock or spindle mount wheels need precise centering features, of course, but if tapered lugs are used a centering ring will only partially influence centering. The way I'm seeing it, if a design uses tapered lugs, they should be left to their job with no other features interfering.

 

Dean