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Technical wheel modification idea : suicidal or not?

Discussion in 'The Hokey Ass Message Board' started by chrisp, Apr 15, 2019.

  1. chrisp
    Joined: Jan 27, 2007
    Posts: 1,048

    chrisp
    Member

    I have those Renault disc wheels from the 20's to early 30's roughly 19" that I'd like to use on a build, then I have those Jaguar wire wheel hubs that have been siting on my shelves for many years that got me thinking : what if I was to combine them together for that 20's race car feel?
    [​IMG]

    [​IMG]
    The idea is to insert the hub inside the wheel : cut the hub at a roughly 4" diameter (getting rid of the wire holes lip) and cutting a 3" hole in the wheel, allowing me to have a flange for the disc to sit on and weld the hub on 2 different circles inside and outside for a stronger joint.
    Do you guys think it's feasible without risking everything to come apart at speed?
    One more thing, I believe the hub is heat treated for the spline drive.
     
  2. I think the cuts need to be done on a lathe and then the welding jigged very accurately to avoid being off centre.


    Sent from my moto g(6) play using The H.A.M.B. mobile app
     
    fauj likes this.
  3. I would be working out the cost and availability of correct tires first. You must know that those French Michelin wheels take old vintage style metric tire size 12 x 45 ( expensive Michelin or Engelbert ) which are not the same as inch sizes.
     
    loudbang likes this.
  4. Ned Ludd
    Joined: May 15, 2009
    Posts: 5,025

    Ned Ludd
    Member

    That was my first thought also. The tyres you intend to run will determine the size and type of rim hoop you need. Then, it seems you only need a slightly domed disc to join those to the hubs: perhaps the ends of some kind of pressure vessel?

    It is easy enough having steel wheels modified where I live. The people who modified the 15" Renault wheels I've got on my Golf Mk1 refuse to band wheels, but will readily weld the disc of one wheel to the rim of another. They will also do setback changes without hesitation. All I needed was the centre hole reduced a bit to fit the Golf hub and a coat of pseudo-alloy silver paint – and subsequently a few passes of a coarse file over the front brake calipers.

    Other firms are confident to band rims to any width you require.

    I had the idea before to build lightweight wire wheels by cutting down OEM alloy wheels to the rims, drilling holes for the spokes, and lacing them to MGB hubs I have. I was advised that OEM cast rims might not be adequate to the purpose, though. Thinking about it again I am wondering if the wheels would not be OK after all if supported at 72 places instead of five and carrying barely half the intended weight. If someone can explain to me exactly what the failure mode of that would be I'll stop this line of thinking immediately.
     

  5. Well, I've seen factory aluminum-rim wire wheels many times, but all of them featured forged or extruded rims. A cast rim would be much more brittle I would think. You could probably make a go of it if the rim thickness was thick enough (.25" or more) and you maintained that thickness as much as possible, but then the difficulty would be 'pointing' the holes in the right direction when drilling them to maintain a straight pull on the spokes. Not impossible, but the degree of difficulty would be considerably higher...

    Too thin and I see the spokes pulling though the rim. I doubt you'd get a catastrophic failure, but I think you'd have lots of 'issues' leading up to that. Maybe have the rim heat-treated after machining, but you'd likely need to know the alloy used to do that.
     
    Last edited: Apr 15, 2019
    Ned Ludd and Hnstray like this.
  6. chrisp
    Joined: Jan 27, 2007
    Posts: 1,048

    chrisp
    Member

    First, yes I know they're metric tires the Michelin run for about 200€. I dream of all white tires but they don't exist in metric. I thought of replacing the hoops, but there's a problem with that : look closely at the pictures, the hoop is not round it's an oval, there is a step on the right and not on the left, so the disc is actually an oval. Why did they do that? Who knows... But that makes replacing the rim impossible if I am to keep them at 19"ish or 450mm.
    Yes Blackjack it will be done on a lathe, today I was replacing the hoops on 1932 Studebaker wheels with hoops from Jaguar X300 spare wheels and I had to shave on my lathe 1 mm off the diameter of the Stude spokes to fit in the hoops. And I will band 2 of them too on a friend lathe which can fit up to 500mm in diameter. I'll post pictures later.
    Ned I would worry that the spoke nuts would dig into the alluminium hoop as time pass by. You can band the wheels yourself. If you don't have a lathe you can use a tire machine to rotate the wheel and attach a grinder on the arm that's used to remove the tires. or even fabricate your own fixture with a wheel hub and bearing and some tubing to locate the grinder and wheel. My friend with the big lathe refuses to band wheels too, I just told him not to worry and just cut the wheels where I want, I take the responsibility of welding. For some kind of "art project" you can have your wheels cut anywhere...
     
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  7. Ned Ludd
    Joined: May 15, 2009
    Posts: 5,025

    Ned Ludd
    Member

    It might be an attempt at a drop well to assist in fitting tyres, but which exists fully only at one point on the circumference? Why, I could not say.
     
  8. chrisp
    Joined: Jan 27, 2007
    Posts: 1,048

    chrisp
    Member

    I didn't think of that, pretty clever.
    Here's what I was doing on my Stude wheels
    [​IMG]

    [​IMG]
    And the 18" Jag wheel hoop donor
    [​IMG]
    That I'm very confident of doing.
    On the Renault/Michelin wheel I'm not afraid of tackling it, I'm just wondering about the technicality, on the other hand the Studey wheel has it's center disc with the bolt pattern welded on a single flange to the spokes with a quite porous weld sooo...
     
    Ned Ludd likes this.
  9. Desmodromic
    Joined: Sep 25, 2010
    Posts: 571

    Desmodromic
    Member

    The rims for wire wheels are provided with hemispherical "dimples" that the rounded side of the spoke nipple nut fits into, and the holes drilled through each dimple are "aimed" towards the corresponding hole on the inner hub. (The dimples are generally stamped, not machined, so there is minimal loss of local metal thickness.) This ensures that the load is distributed evenly 360 degrees around the nut base.

    The static load on the wheel (weight of car) is not carried by 72 spokes, which cannot accept shear or compressive loads. In essence, the car is "hanging" on the spokes at the top of the rim; adjacent spokes carry a partial load, and the spokes on the bottom half of the wheel do not participate at all. When cornering (say, going right), the transverse force on the left wheel at road level creates a moment on the hub, that is absorbed by the lowest outer spokes, and the inner upper spokes, all in tension. On the upper spokes, this load is additive to the static load.

    Executive Summary -- To save a pound or two with thick alloy rims vs. thinner steel rims, at the high conversion cost and risk in reliability, would be better to go on a diet for a week, which would also lower the center of gravity of the car/driver combination, which is a good thing.
     
    Ned Ludd likes this.
  10. Ned Ludd
    Joined: May 15, 2009
    Posts: 5,025

    Ned Ludd
    Member

    Thanks for an eminently rational answer!
     

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