boneman Posted February 23, 2019 Report Share Posted February 23, 2019 Hi all, I'm a new owner of 2015 Lexus is 300h F Sport and I notice the inner tread band of both the rear wheels is wearing a lot more than the rest of the tyre width. The cars done just over 11000 miles and is on original Bridgestone Turanza all round and I've driven the last 3000. After a bit of googling it seems the earlier IS300's had a similar tyre wear problem and you guys sorted it out. I use the car for motorway journeys so I guess the wheels need to stand up straighter ie reduce the -ve camber. After years of Impreza and Octavia vRS I'd thought I'd escaped the 4 wheel alignment with you guys but here I go again. Hopefully you guys can sort this out for me with some more appropriate geometry. Regards, Mike Quote Link to comment Share on other sites More sharing options...
Tony Posted February 24, 2019 Report Share Posted February 24, 2019 Lexus got the rear toe position wrong hence the reason many 300h owners have this rear wear issue. Basically we reduce the toe-in. The IS300 had incorrect front castor position. Problem is it's not directly adjustable but it is indirectly by moving the camber position. Quote Link to comment Share on other sites More sharing options...
boneman Posted February 24, 2019 Author Report Share Posted February 24, 2019 Thanks for your reply Tony. I don't know any of the geometry angles but on a straight road I assume the car is running with -ve camber and toe in at the rear. So its got more weight on the inner band of tread and combined with the toe in results in scrubbing of the inner treads. Do your revised angles fall within the Lexus tolerances and what effect will new settings have on straight line stability and turn in etc? The Octavia vRS had similar problem and iirc the camber and toe were both reduced and rear tyre wear was not an issue. In the past I've had to discover the best settings for the scooby and the vRS and always had to make sure the local alignment tyre people adjusted to the settings I wanted and not just within the wide tolerances of the car manufacturer. Do I need to make appointment or just turn up and wait? Mike Quote Link to comment Share on other sites More sharing options...
Tony Posted February 24, 2019 Report Share Posted February 24, 2019 The issue is the toe not the camber. Camber wear is violent and confined to about 10% of the tyres width whereas the toe wear is subtle and could involve the total tyre width. When we evolve a handling package normally the rear camber is made more aggressive since this is the point under/ oversteer is controlled and since the rear on most cars is lighter than the front additional camber isn't sacrificial. Rear toe is not so forgiving since the lateral scrub is a constant whereas camber has a curve. All cars have to be booked in. It's only way to control waiting times. Quote Link to comment Share on other sites More sharing options...
boneman Posted February 24, 2019 Author Report Share Posted February 24, 2019 Do you have settings which are more suitable for motorway driving rather than the twisty stuff? Quote Link to comment Share on other sites More sharing options...
Tony Posted February 25, 2019 Report Share Posted February 25, 2019 On motorways the aerodynamics are loaded, so we pull the car down to see how much the toe migrates. All cars are slightly different depending on the suspension. Quote Link to comment Share on other sites More sharing options...
boneman Posted March 6, 2019 Author Report Share Posted March 6, 2019 Hi Tony, My car was in WiM yesterday for setup. rears were toeing out 04' & 07' and front ns 09' out and os 07' in. now rears are toe in 05' & 03' and front 00' & 01' in. Cambers all ok and at lower end of range. Joe advised me this will be better for tyre wear and also economy which I hadn't considered. Car better to drive now, it was ok before but now more precise steering and feel on the road. So thanks to all. Quote Link to comment Share on other sites More sharing options...
Tony Posted March 7, 2019 Report Share Posted March 7, 2019 Your welcome The initial toe out is not a nice drive, whereas toe in makes the steering feel more secure. Quote Link to comment Share on other sites More sharing options...
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