Hub concern

[Dave K]

I'm designing some live-spindle uprights/hubs this year, and have a concern.. the brake caliper and whatnot has to be fit inside the wheel, which puts the hub-mounting flange a decent distance from the upright (a little less than 1.4 inches)... i am concerned with high bending moments on the spindle at the wheel mount. does anyone else have this kind of concern?


here's a concept picture... not necessarily what the finished product will be, but you probably get the picture...

http://img140.imageshack.us/img140/6169/65677363ub2.jpg

[nickerss]

How big are your brake rotors? If you are really worried about the bending load on the spindle, you could put your rotor on the inboard side of the upright to move the wheel mounting flange closer to the upright/shorten the spindle.

What material are you using for your spindles? Out of curiosity (I'm assuming you are doing some FEA on this), what kind of loads are you applying that is making you worry about the bending moment?

[mtg]

If you rethink the packaging a bit, you can reduce that distance.

The bending isn't a problem if you design the hub and upright strong enough to handle it. But, if you can reduce the distance via different packaging, you can make the whole setup lighter.

Try looking through a bunch of pics from comps- there's lots of pictures of corners out there.

[Dave K]

Yeah, it'll be 4130 heat-treated. I am pretty sure i have the numbers correct for the FEA, i am using full cornering loads (about 2 gs), which gives me about a ~4500 in-lb moment at the mount flange.

[Frank]

it is the bending moment from cornering that dominates side force x radius of tyre

the offset dosn't do much

dont use sharp corners on hubs, as pictured at the "back" of the wheel mount.. you waste strength due to the stress concentration (3 times weaker)

for reasons above, don't use sharp corners in the places where bearings locate axially, investigate chamfered spacers as pictured in carol smith books

[Dave K]

Thanks guys, helps a lot. Yeah, that moment is from calculated side cornering x tire radius.

And don't worry, i am adding radii to the corners once i get farther haha