Roger440 Posted August 3, 2006 Report Share Posted August 3, 2006 One of my customers has recently taken his car back to the main dealer as a result of uneven tyre wear at the rear. They have twiddled a bit and now the cars pulls to the left. He has sent me the results before and after. The rear camber on the left is well out by nearly a degree, should be 1-1.5 degress, but i don't think that is where his problem lies (though something is clearly not right). They seem to have corected the small toe out at the rear so have probably stopped the wear issue. More interesting is the difference in castor. Given the spec is 7.5 degrees, i amazed that they are as high as they are, but more important uneven. They have also dabbled with the front camber, which is factory adjustable on Vauxhall Monaros. Any views? Am i missing something? Sorry if its hard to read, struggling to manipulate my IT"! Rear Axle Initial Final Camber Left -0o18' -0o20' Right -1o19' -1o21' Individual Toe +0o10' +0o04' -0o05' +0o05' Total Toe +0o06' +0o09' Setback +0o10' +0o04' Geometrical Driving Axis -0o07' +0o01' Front Axle Castor 20o +9o22' +9o19' +8o44' +8o51' KPI 20o +5o28' +5o45' +6o08 +5o16' Toe Out on Turns -1o58' -2o17' -1o46' -2o09' Camber -0o50' -0o21' -0o28' -0o28' Individual Toe +0o10' +0o05' +0o10' +0o05' Total Toe +0o20' +0o09' Setback -0o15' Included Angel 20o +4o41' +5o24' +5o38' +4o47' Max Steer to Left +39o48' +39o24' +31o53' +31o32' Max Steer to Right +32o17' +31o19' +41o21' +40o40' Quote Link to comment Share on other sites More sharing options...
Tony Posted August 3, 2006 Report Share Posted August 3, 2006 Any data avalible for the 'trim height' on each corner please. Quote Link to comment Share on other sites More sharing options...
Roger440 Posted August 3, 2006 Author Report Share Posted August 3, 2006 Any data avalible for the 'trim height' on each corner please. Sadly not, thats all ive got. I did work on it recently though (not suspension!) and it wasn't visibly leaning at all. Quote Link to comment Share on other sites More sharing options...
Tony Posted August 3, 2006 Report Share Posted August 3, 2006 Any data avalible for the 'trim height' on each corner please. Sadly not, thats all ive got. I did work on it recently though (not suspension!) and it wasn't visibly leaning at all. Ok mate i will work on what data we have available. Quote Link to comment Share on other sites More sharing options...
IanF Posted August 4, 2006 Report Share Posted August 4, 2006 There are three HSVs and two VXRs in the car club I belong too. I don't know if its possible to get comparative data from them. Most if not all the comments on the quality of Vauxhall main dealer competence would be unprintable. Quote Link to comment Share on other sites More sharing options...
Tony Posted August 4, 2006 Report Share Posted August 4, 2006 Studied the data again and there is no Geometrical reason i can see. If this were my customer these would be my next steps. 1: Determine if the pull is physical or a tyre drift 2: Measure the trim height since the front has Torsion bars 3: Test the power steering valves/pressure 4: If needed manufacture the Geometry to compensate (last resort) Quote Link to comment Share on other sites More sharing options...
Roger440 Posted August 4, 2006 Author Report Share Posted August 4, 2006 Hi Ian, That wouldn't be the autobahnstormers by any chance? Tony, Do you not think the difference in castor left to right could be an influencing factor? A good 3/4 degree there. The front suspension is not torsion bar, just regular Macpherson strut, hence unlikely to be hight related, but worth checking anyway. Given the difference in camber at the back, there will be a greater rolling resistance on one side, but i can't imagine that this would give rise to any problem? The car DID drive OK prior to its alignment check. Thats not to say it was right though!!!! Quote Link to comment Share on other sites More sharing options...
IanF Posted August 4, 2006 Report Share Posted August 4, 2006 Hi Ian, That wouldn't be the autobahnstormers by any chance? Yep Very helpfull group Quote Link to comment Share on other sites More sharing options...
Roger440 Posted August 4, 2006 Author Report Share Posted August 4, 2006 Said customer is now no longer sure it pulls, more that is is less stable/direct in a straight line than it was before! Now he tells me This makes more sense. The total toe has been reduced from 20' to 09'. Spec is 5-10'. However, given that virtually every Monaro i see has inner tyre wear, and are not directionally stable.,when checked everything checks out to spec. I experimented with mine at 20' which relly helped. Did another one today after fitting a full coilover kit and set it to 20' total toe. Drove superbly, really stable. The more i do of these, the more convinced i am that the factory spec is wrong. I'd still like to know the likely effect of the castor difference though. Quote Link to comment Share on other sites More sharing options...
Tony Posted August 4, 2006 Report Share Posted August 4, 2006 Hi Ian, That wouldn't be the autobahnstormers by any chance? Tony, Do you not think the difference in castor left to right could be an influencing factor? A good 3/4 degree there. The front suspension is not torsion bar, just regular Macpherson strut, hence unlikely to be hight related, but worth checking anyway. Given the difference in camber at the back, there will be a greater rolling resistance on one side, but i can't imagine that this would give rise to any problem? The car DID drive OK prior to its alignment check. Thats not to say it was right though!!!! No the castor values invite a pull to the right if at all... The rear os camber wants to push to the ns so again suggest a corrective attitude to the right... but saying that i would test this under thrust, and then rolling without thrust in case the application influences the conical effect... the tyre aspect ratio is so high who knows how much they will distort? Quote Link to comment Share on other sites More sharing options...
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