CIH Posted November 10, 2009 Author Report Share Posted November 10, 2009 One thing my book mentioned was degrees of Ackermann. Saying a standard domestic car runs about 1/3rd full effect. Unlike say a Taxi, or presumeably a little Sooty van, with tight turning circles which run full ackermann. Quote Link to comment Share on other sites More sharing options...
Tony Posted November 11, 2009 Report Share Posted November 11, 2009 Should also note taxi's and sooty vans normally have a "true" kingpin to allow the Ackermann. Quote Link to comment Share on other sites More sharing options...
CIH Posted November 15, 2009 Author Report Share Posted November 15, 2009 what an actual kingpin rather than a "theoretical" kingpin ? Quote Link to comment Share on other sites More sharing options...
Tony Posted November 15, 2009 Report Share Posted November 15, 2009 what an actual kingpin rather than a "theoretical" kingpin ? Â Yes.... The real terminology for Kingpin stems from the cart where the rotational axis was vertically linked to the steer axis..... King-pins in the true sense have no inclination/ declination. Quote Link to comment Share on other sites More sharing options...
CIH Posted November 15, 2009 Author Report Share Posted November 15, 2009 No not at all, it's an important area. I'll get some screen shots tomorrow taken at 20 degrees, hopefully with images it will make sense. Â Just a friendly reminder dude Quote Link to comment Share on other sites More sharing options...
Tony Posted November 16, 2009 Report Share Posted November 16, 2009 No not at all, it's an important area. I'll get some screen shots tomorrow taken at 20 degrees, hopefully with images it will make sense.  Just a friendly reminder dude  Noted....... Quote Link to comment Share on other sites More sharing options...
Tony Posted November 17, 2009 Report Share Posted November 17, 2009 Correctly set chassis (ignore the red, that's intentional for this car)  Now 20 degrees left  And 20 degrees right  What do you see? Quote Link to comment Share on other sites More sharing options...
CIH Posted November 17, 2009 Author Report Share Posted November 17, 2009 Toe Migration is inconsistent Quote Link to comment Share on other sites More sharing options...
Tony Posted November 17, 2009 Report Share Posted November 17, 2009 Look at the camber and castor migration..... visualize the positions of the wheels and the attitude profile of the car. Quote Link to comment Share on other sites More sharing options...
CIH Posted November 17, 2009 Author Report Share Posted November 17, 2009 Is the toe activity the primary reason for SR migration ? Quote Link to comment Share on other sites More sharing options...
Tony Posted November 17, 2009 Report Share Posted November 17, 2009 Is the toe activity the primary reason for SR migration ? Â No, the castor. Toe is beside the point if you look at the massive changes in camber/castor. Quote Link to comment Share on other sites More sharing options...
CIH Posted November 17, 2009 Author Report Share Posted November 17, 2009 I can understand the camber gains (KPI I think ?) and the Toe gains but where is the extra castor coming from ? Quote Link to comment Share on other sites More sharing options...
Tony Posted November 18, 2009 Report Share Posted November 18, 2009 Remember the castor position is taken on a 20 degree lock. As the steering is turned the pivotal points orbit around a moving axis.... Try this> in the shop turn the cars steering left/ right and notice how the bonnet oscillates, ask yourself why? How can turning the steering make the bonnet rise and fall? Quote Link to comment Share on other sites More sharing options...
CIH Posted November 18, 2009 Author Report Share Posted November 18, 2009 We've already covered this . As the wheel shifts it's posture it would drop below the road surface, but obviously can't, so insted it pushes the the front of the car up. Â Oh right so, looking at the inner wheel of the turn, it's essentially the spring becoming unladen that accounts for the extra castor (so to speak) ? Quote Link to comment Share on other sites More sharing options...
Tony Posted November 19, 2009 Report Share Posted November 19, 2009 Point is and in answer to your question, as the height changes the projection of the castor through the upper/ lower pivotal points changes. Quote Link to comment Share on other sites More sharing options...
CIH Posted November 19, 2009 Author Report Share Posted November 19, 2009 Sweet! Â Could we explore how the process can go wrong ? Such as with the OEM IS200 positions ? Quote Link to comment Share on other sites More sharing options...
CIH Posted December 4, 2009 Author Report Share Posted December 4, 2009 consider yourself prodded. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 4, 2009 Report Share Posted December 4, 2009 consider yourself prodded. Â Noted...... Back on track this weekend, i'm trying to deal with some c**k on a Merc forum at the moment and he's really draining my time Quote Link to comment Share on other sites More sharing options...
CIH Posted December 4, 2009 Author Report Share Posted December 4, 2009 No worries. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 5, 2009 Report Share Posted December 5, 2009 No worries. Â Have a read> http://www.mbclub.co.uk/forums/wheels-tyre...lsinmotion.html Quote Link to comment Share on other sites More sharing options...
CIH Posted December 12, 2009 Author Report Share Posted December 12, 2009 Some people just don't like to have their opinions challenged...... Quote Link to comment Share on other sites More sharing options...
Tony Posted December 12, 2009 Report Share Posted December 12, 2009 Some people just don't like to have their opinions challenged...... Â Did me the world of good.... The thread got around 2.5k veiws and i have endless Merc's to calibrate, i held me cool "more or less" but this type of thread sucks your time. Â Anyway, your training thread, where was we Quote Link to comment Share on other sites More sharing options...
CIH Posted December 12, 2009 Author Report Share Posted December 12, 2009 I asked what happens when the castor/camber/toot relationship fails, such as IS200s with OEM positioning. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 12, 2009 Report Share Posted December 12, 2009 Ah yeah...... Research for me was the first port of call. A -30' OEM front camber is not aggressive but the tyre wear (10% on the inner) to the wire in 5k is. Â I set some test cars to the OEM front camber of -30 then turned the steering 20 degrees (limited information on that machine) and noted the outer wheels camber migration to -1 degree 20' or there abouts. Toot at 20 degrees, inner wheel +1 degree 45'. Â From further research i found there was three global positions for castor, Asian, European and UK but this angle if fixed so how can there be three arrangements My desire was to increase the fixed castor position so i found this solution. Â Move the camber to -15', this totally violates the toe and when this is corrected it pulls the castor forward an additional around 45'. So the castor can be adjusted "indirectly". Â On testing the outer wheels gain on lock (20 degrees) was to -55', 15' over stock static, 40' over my static position but still a dramatic reduction. The cars where then tested in the field and in the case of the Lexus IS200/ 300/ 300sc i hit the nail on the head first time.... Happy days. Â Point of the project was to realize the criminal?.... The wear was obviously camber but the OEM static position was sedate, so where was this wear happening.... Answer "on the corner". The only adjustable tools where the camber/ toe and since camber is the most aggressive angle that was the one to work with. Quote Link to comment Share on other sites More sharing options...
CIH Posted December 13, 2009 Author Report Share Posted December 13, 2009 I've always thought deeper static castor meant deeper camber gains on turn ? Quote Link to comment Share on other sites More sharing options...
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