Engineering/wheel hub question
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Team Owner
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Engineering/wheel hub question
I'm curious about why a wheel to hub attachment takes 5 pretty chunky.lugs but the hub to spindle only requires three moderately sized bolts? It would seem the forces exerted to the wheel lugs would equally be present at the hub and would require just as much support.
Tech Contributor
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From: Should this thoughtful, valuable contribution meet with no acknowledgement or 'thanks' this post----
It has to do with the larger radius of the road wheel. When cornering the force at the tire face is transmitted back to the attaching point over a greater distance, therefore, is much greater. Also the size of the wheel stud and the hub fastener is important to overcome the applied loads.
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Team Owner
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I considered this as well. The thing is, the same force exerted on the lugs is carried through to the hub. Possibly even greater when you consider the leverage of the wheels against the hub bolts. The wheel acts as a huger lever agains the hub and the force doesn't stop at the lugs. Either the hub bolts are a potential fail point, or the wheel lugs are way overkill.
Pro
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From: San Antonio Texas
Remember that the original Vette and most racing cars of the day had center knock off type wheels. Yes it is one big nut and spindle but the forces are not that great. I believe that the five lug design was more about making sure the wheel was on center and perpendicular to the axle plane. Also, a five lug will straighten out a bent wheel to some extent and minimize the effect.
