Section : Suspension

My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

Posted By : William Fawcus, 25-Nov-2005, 08:29pm

• My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

  Posted By : Colin Wake, 25-Nov-2005, 09:24pm

  Will
  
  As a general starting point, there shound be 3 shims behind each of the 4 brackets where the lower wishbone attached to the main chassis rails. 2 brackets each side.
  
  Is all the front suspension standard to your knowledge??
  
  Colin

  • My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

    Posted By : William Fawcus, 25-Nov-2005, 11:25pm

    As far as I know the front suspension is all standard
    

    • My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

      Posted By : Roy Lacey, 26-Nov-2005, 08:58am

      The camber adjustment shims are in most of the big parts catalogues
      Part no-122022 (canleys £1.25 each)
      Roy.

      • My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

        Posted By : John Davies, 26-Nov-2005, 09:18am

        William,
        Have a look at this webpage, from the Rimmers website, that shows a diagram of the front lower wishbone, spring and shock absorber.
        
        
        
        Image Courtesy of and Copyright Rimmer Bros Ltd
        
        You can see the shim (only one shown but you will need more)at the base of the rear arm of the 'bone, labelled 122022. They are easy to remove or add, if you put the car on stands, loosen the nuts on the opposite side of the chassis rail (GHF 223) and raise the upright with a jack. They slide in from above, each one sitting a little higher than the one below, due to the bent-over tip. This should make it fairly easy for you to count how many shims you do have.
        
        How about a photo? And please tell us how you get on.
        
        Like many who have had Triumphs for long, I have boxes of these shims, if I can find the box, to which you are welcome, but they are very cheap to buy as Roy shows.
        
        JOhn

• My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

  Posted By : Nigel Gibbins, 26-Nov-2005, 02:42pm

  As you have said your tyres have worn unevenly I would suspect that your tracking is probably more to blame than your camber. Since you say that the excessive wear is on the outside of the tyre then I expect you have far too much toe-in.
  
  If you indeed have no shims at the bottom ishone then I'd further suggest that your geromery is completeley off. This means camber, castor and toe and in this state I am not surprised at all that your tyres were quickly shot to pieces.
  
  As a general starting point I would put two shims behind the front wishbone mount and four shims behind the rear. There is of course no guarantees that this is right for boht sides though as more often than not the front suspension shims were used to even out any chassis imperfections - so you may find that one side need more shims than the other to get it all spot on.

  • My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

    Posted By : Jonathan Pashley, 27-Nov-2005, 09:46am

    Nig
    I have just re-built the front suspension on my MkIV and there was only one shim per mounting point
    I know I have got to get the tracking done but how do you check the rest of the geometry?
    
    Jon Pashley

    • My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500

      Posted By : John Davies, 27-Nov-2005, 10:40am

      Jonathan,
      Castor is the angle between the vertical and a line betwen the upper and lower steering swivels. If you can fix a spirit level up vertically next to your suspension and measure the distances from the ball joint and trunnion, a little maths tell you your camber. Resetting it is a matter of adding or removing shims from the front or rear the lower wishbone brackets
      
      I wrote the following for another site, but why not put it here too:
      Camber is the lean-in, or out, of a wheel, in other words the distance that the top of the wheel is nearer to, or further away from the midline of the car. In general, a small amount of lean-in, with the top nearer to the midline, is desirable and this is called 'negative', camber. Negative camber is desirable to keep the tread of the tyre as flat as possible on the road while cornering. You can see why this is so with a pencil rubber or eraser.
      
      Simulating negative camber.
      Hold a rectangular rubber with your right thumb and forefinger. The rubber is the wheel and tyre and your finger is now towards the midline of the car. Press the rubber down hard against a tabletop, and try to pull it towards you. You are now simulating the outside wheel of a cornering car, and the centrifugal force trying to pull the car out from the centre of the corner.
      Look at the under side of the rubber, as you pull, the edge towards you catches, and the side away lifts. This is what a tyre tries to do in a corner, lifting the inside edge of the tread. The more tread on the road, the more grip, so a tyre in this situation will probably skid.
      But tilt the rubber away from you, towards the midline of your imaginary car like a tyre in negative camber. Push down and pull towards you as before. The lower edge of the rubber now lies flat against the table surface. More of the tyre's tread will be on the road and the grip of the tyre will be as good as possible.
      
      Spitfire wheel camber.
      All Triumph Herald based cars, including Spitfires, were built with a slightly positive camber, as this minimises tyre wear, but common modifications will change the camber.
      Model Front camber: Degrees
      All Spitfires + 3.0 +/- 1
      GT6 Mk1 +3.5 +/- 1
      Mk 2 & 3 +2.75 +/- 1
      Herald (laden) +2.0 +/- 1
      All Vitesse +3.25 +/- 1
      
      Front springs. The double wishbone (A-frame) is the suspension layout that gives the best compromise when all factors are involved. However it does not maintain the same camber all the time, as the wheel moves up and down. Many owners change to stronger, shorter front springs, for lower ride height. The lower ride height brings the front suspension into a different part of the arc of movement. In this part of the arc, the camber will be different, and may change more as the wheel moves up and down.
      Adjustable shock absorbers. These allow the lower spring support to be adjusted up and down, altering the ride height and the balance of the car. They will also effect on the arc of movement of the suspension.
      Lower wishbone brackets. Triumph not only provided us with the best type of suspension, they also made it adjustable! The lower wishbone brackets have shims between the bracket and the chassis rail. Adding shims will push the lower wishbone bracket out, and the top of the wheel in, into negative camber. You can add more than half an inch of shims if you really want to, without running out of thread on the bracket bolt!
      
      Making a camber gauge.
      After modifications like this, you should measure what has happened to the camber. This gauge will make it easy to do so. Make it out of a piece of folded metal sheet, drilled as shown to take the wheel studs. The curved edge below the holes leaves clearance for the jack, used to move the wheel up and down. A central hole is also needed, to clear the hubcap (the pictures show my suspension, with a large wheel spacer that covers the hubcap). Plywood, with a batten on the edge to take the measuring face would do as well.
      The dimensions of the gauge are not critical, but should be large enough to take the wheel stud holes. Dimension D, the height of face A, should be 350-400 mms, to allow you to measure very small angles.
      Mark a line down the middle of face A, and a scale along the lower edge, either side of the midline. See the diagram. File a tiny V in the edge at the top of the vertical line.
      
      The scale needs to be calculated from dimension D, as follows:
      Degrees 0.5_______1________1.5_______2_______2.5______3________3.5______4
      
      To find the distance of each scale mark from the midline multiply Dimension D by:
      ______0.009_____0.018_____0.026____0.035____0.044____0.053____0.061____0.07
      (these numbers are the trigonometric function Tangent of the angle in degrees)
      
      For example:
      If D=370mm; then distance of each mark from midline, in mms, will be:
      ________3________6.5______10_______13________16_______19.5_____22.5_____26
      
      I have rounded the distances to the nearest 0.5mm, as I can't see smaller than this!
      I recommend using millimetres, as inch fractions in decimals are much more difficult.
      (The underlinings in the above lists are to maintain tabulation on the screen)
      
      How to use the camber gauge.
      Position the car on a level surface; Secure the car with chocks at the rear wheels.
      Put someone in the driver's seat, or a suitable weight.
      Measure the height above the ground of the outer end of the lower wishbone.
      Measure the height of the chassis rail at a suitable point.
      Place a jack under the wishbone, and raise the wheel off the ground.
      Remove the wheel.
      Place a strong support under the chassis rail, and lower the car to the same height as before. Wood blocks and plank offcuts are best. NOT bricks!
      Put the gauge onto the hub, over the wheel studs.
      Using the jack, adjust the wishbone to the same height as before.
      Hang a plumb bob over the edge of face A, from the V at the top of the line.
      Tape on the back of face A will hold the line in place.
      Read the camber angle at the lower edge.
      
      This figure is the camber angle at rest. If you remove the spring and shocker, you can work the suspension from full droop to bump, reading the change in camber angle all the way. The ideal is for the camber to stay the same throughout the arc of movement, but this will not happen! Adjust the shock absorber spring seats, and the wishbone bracket shims to get the minimum change.

      
      
      My Front Wheel camber is completly out and not sure what to do - 1976 Spitfire 1500