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Thread: Hub Rotor and Upright Benchmarking Project

  1. #1
    Hello All,

    I need to do some Benchmarking for my Senior Design project. I would like to know some typical weights of the hubs rotors, and uprights from other FSAE teams. Our un-sprung weight for the front is about 10.25 lbs minus the wheel/tire and brake caliper. Also, would anyone care to discuss upright stiffness? We would appreciate any help you can give.
    SAE/FSAE President 05-06 Suspension Team Leader 06-07

  2. #2
    Front:

    Wheel Bearing: .44 lb
    Brake Caliper: 1.40 lb
    Hub: 1.10 lb
    Centerlock Nut: .13 lb
    Upright: 1.65 lb
    Brake Rotor: 1.5 lb (tentative)
    Fasteners: .15 lb (approx)
    Total: 6.37 lb

    Rear:

    Wheel Bearing: .44 lb
    Hub: 1.47 lb
    Centerlock Nut: .13 lb
    Upright: 1.50 lb
    Tripod Housing: .51 lb
    Fasteners: .10 lb (approx)
    Total: 4.15 lb
    Colorado FSAE | '05 - '07
    Goodyear Tire & Rubber | '07 - '11
    NASCAR Engineer | '11 - ??

  3. #3
    Senior Member
    Join Date
    Oct 2005
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    Posts
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    Originally posted by Jersey Tom:
    Brake Caliper: 1.40 lb
    Building your own or which brand?
    KTH Racing '03-'08
    Dartmouth Formula Racing '07

  4. #4
    Wilwood Billet DLS. Doesn't include the pads, but that is the caliper itself. The PS1 is lighter.
    Colorado FSAE | '05 - '07
    Goodyear Tire & Rubber | '07 - '11
    NASCAR Engineer | '11 - ??

  5. #5
    Front:

    wheel bearing: .44lb
    brake caliper: 1.4lb
    hub: 0.65lb
    upright: ~1.3lb
    brake rotor: 1.4lb
    Fasteners: ~.2
    Rutgers Formula Racing (05,06,07)
    Vice President

    Persistence...
    "Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a p

  6. #6
    c'mon guys, you can't spray about how light your stuff is without some stiffness numbers. how about everyone list there camber gain at 2 G's?
    jack
    College dropout extraordinaire
    (formerly WWU Rev-Hone Racing)

  7. #7
    Originally posted by jack:
    c'mon guys, you can't spray about how light your stuff is without some stiffness numbers. how about everyone list there camber gain at 2 G's?
    I don't want to hear anything about FEA either. I'd be interested in honest to god tested numbers.

  8. #8
    Originally posted by LD:
    Front:

    wheel bearing: .44lb
    brake caliper: 1.4lb
    hub: 0.65lb
    upright: ~1.3lb
    brake rotor: 1.4lb
    Fasteners: ~.2
    stiffness was 31,333 ft*lb/degree
    which for us translated into <0.009 degrees camber change at 1.65 G's cornering

    also check out this post
    Rutgers Formula Racing (05,06,07)
    Vice President

    Persistence...
    "Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a p

  9. #9
    You guys are silly. Our uprights and hubs are made out of STRAIGHT UP METAL. Can't bend that.
    Colorado FSAE | '05 - '07
    Goodyear Tire & Rubber | '07 - '11
    NASCAR Engineer | '11 - ??

  10. #10
    Be very wary of assuming that your bearing package is infinitely stiff, and pay close attention to properly applying your loads and constraints on any FE models you use. Not paying attention to the bearing to upright connection can be misleading and show much more stiffness than what you will actually get. That is in the upright structure alone, and you still must consider the stiffness of the bearing itself. It is likely a significant contributor of deflection. Physical testing of your assembly will show that the stiffness you actually get is not anywhere near as high as analysis of just your structures will show.

    At the UW, with our 2 lb 96,000 in*lbs/deg upright structures, .9 lb bearings, 2 lb axles/studs/wheel nuts, 1.4 calipers, and 1 lb rotors, we only saw around 30,000 in*lbs/deg of camber stiffness at the wheel hub from physical testing. Because you are working with springs in series, you must consider your wheel, axle/spindle/hub, a-arms/rod ends/spherical bearings, and chassis as well if you want to get an idea of what the whole assembly will do. If you work a lot on stiffening the part that is already the stiffest, it will not do you much good as the overall assembly stiffness will not change much. It's best to look at all of the parts in the system rather than any particular parts alone.

    During my time at the UW, we determined our desired stiffness based on an approximate static camber angle and our kinematic deflection and a minimum dynamic camber. Using our floppy 2003 car as an initial mule, we analyzed and physically tested our stiffnesses as a baseline, and for around the same weight managed to more than double and triple the stiffness for the following two cars by stiffening up the most floppy parts.

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