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Tony-Bones

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Everything posted by Tony-Bones

  1. If you go lower than 35mm you could have issues with the damper strock on bump.
  2. Yes, make sure it's a full geometry including the castor angle, not one of those "toe and go" jobs that only sights one angle of fifteen.
  3. As said i don't want to hijack this thread but i there is some relevance within the reply that contributes to the problem. Castor is a bugger of an angle to explain because it has so many duties and is very dynamic. So if you want to swat up and can't sleep then read this from my site> http://www.wheels-inmotion.co.uk/tech-longcastor.php I understand you training situation, blimey i was there once myself but like you i needed more information so i trained myself and this is going back to before the Internet. One thing i will say is "ALWAYS" do a castor swing even if you know the angle is not adjustable! Knowledge is power so get the full picture rather than a cheap "toe and go". Which is what your manager would like. Back on topic As just said most places won't measure the Lexus castor position because it's not adjustable, problem number one..... Understanding the interaction between the camber/ castor/ Ackermann angle ( TOOT ) = Toe-Out-On-Turns and the lock angle surpasses toe and go so the real problem gets missed, problem number two. As said i found moving the front camber position to -10' will murder the front toe position toward ( positive ) The toe correction is in a safe direction since the steering arms are screwed in the end not out. Ok your going to loose some lock angle so now your 3 point turn will be a 3.5 turn. On the Lexus the toe's pivotal point is aft of the lower ball joint meaning it's correction will pull toward the front control arm and it's this perpendicular correction that indirectly moves the castor positive. Then the interaction between the castor/ camber and Ackermann during yaw has changed. I know this must all read ???? but it's why the Lexus has issues and remember the manufactures OEM settings are nothing more than a "SUGGESTION", they are not the law!
  4. It's kind of rude to interrupt this thread ever more so since i'm mentioned but i feel some clarity would help..... @Funky Monkey, I worked at your parent company Stapelton's tyres for 25yrs at head office Watford and after going my own way i found myself training your instructors and some of my old area managers!! Anyway as you know they bought Kwick-Fit and have adopted the vision "tracking" is a thing of the past hence the Hunter acquisitions..... Well having it and knowing how to drive it are very different things. Now your only as good as your training and you read really keen to do a good job "stick with that attitude" but there's a long way to go and i'm sorry to say in house the team don't have a clue above basic. Quick example because i don't want to highjack the tread..... I was training your instructors but not knowing their level of knowledge i start with a simple question? "Tracking", front wheel alignment, what's it for? Some smug answers come back "to stop the tyres wearing"..... Um no i asked what's it for? Why is FWD cars front toe position different to RWD cars? Why does wheel size matter? Oh at the most simple of angles they are stumped . Back on topic The IS200/ 300/ SC issue is the castor position? In it's natural position it's unremarkable and not directly adjustable but it can be adjusted indirectly..... Here's where it gets a bit dirty? The problem we have is front camber migration. The actual listed camber positions are very low -21' stock, -30 sport so nothing to drastic there but the low castor and camber migration during yaw, or lock shall we say allows the outer wheel to lean to far negative. I wrote a new front camber position that during adjustment violates the toe which in turn when corrected moves the castor...... Point to note is no cars steering pivotal points are at right angles so any adjustment/ correction will be reflected.
  5. Spot on so well done with your research, many get it wrong i'm afraid. Apart from the looks can you feel a benefit from the wider track?
  6. Nice looking car..... Question though are the spacers hub centric and...... Sorry to read negative you've taken 15/ 20mm of thread away from the wheel nuts so how many turns do they have on the studs now?
  7. They also have the fast-road settings i wrote for the MX5 MK1/ 2/ 3..... Tiss a small world :D
  8. Problem will be the settings.... As TomW kindly said the OEM settings don't work for the IS200/ 300/ SC in the UK. I think my revised settings are still here in the knowledge bank if that helps.
  9. A space saver is the way to go..... You cannot use run-flat-tyres unless you downgrade the suspension and/ or technically change the wheels since the RFT has a different bead line compared to a conventional tyre.
  10. As above and no the geometry will remain the same with new bars fitted.
  11. Thought it was that..... That's why it took a few miles before the vibration.
  12. If bent it will need to be replaced and then the geometry set.
  13. PSI works best at 35 f/r not the 33psi listed. Wheel repair around £70 for a diamond cut.
  14. I the vibration there when you first set-off or does it begin a few miles later?
  15. Have a look at the lower-arm before you go buying parts. The arm in question is the bottom one bolted to the hub/ centre of the wheel. Since the camber position is positive the arm should be bowed where it meets the cross-member? In addition look at the pick-up points where the upper wishbone is mounted just in case it's been pulled away. From the picture it looks like the toe ( longitudinal ) position is reasonably ok so the lateral link/s should be fine.
  16. Any plus gas on the adjusters would help.... As for the rear, yes normally this would need correcting. Don't be alarmed though, the reason the rear camber and toe is adjustable is by design Lexus knew the positions would change over time.
  17. If the sale goes though us then i police the settings they will use and open a live link with them during the calibration to resolve any problems. I also require them to give me a copy for the end positions to ensure all is well. Sad thing is when i opened the network only members i trained could do the calibration but fast-fit staff turnaround is so fluid i found untrained people where doing the work and i wasn't informed. It's a hard call my end and hard to police but it's still working just not really viable my end since money is the do all and end all.
  18. Yes.... Human error? The only requirement the machine relies on is the human setting the final steering position. Well my perception of level may differ from yours since the column is angled as is the dash so it's an issue of perception.
  19. Trust me i'm not trying to educate the world nor am i god when it comes to chassis or suspension calibration plus i have my own operation to run but i am an instructor in my field for the biggest fast-fit empires in the EU and the ignorance scares me! Years ago i acknowledged my best way to help is in places like this and try to offer a smattering of knowledge so you the reader can expect more and know what to expect and why. In this dreadful climate money matters to us all and as we know tyres are not cheap so a p$ss poor geometry will cost you eventually when the front tyres are duffed in 5k. As said the stock IS200/ 300/ SC has chassis issues due to Lexus's belligerent reluctance to offer a solution, in truth they left the solution to late opening the door to liability and litigation that could cost millions.... Well i did offer a proven solution and the datum is available here in the clubs knowledge base. What i find now since the IS is getting mature more owners lean toward modifying the car, albeit lowering of turbo or whatever, this realm is dangerous when it comes to calibrating the chassis in order to compliment the modifications. Sadly few fast-fit outlets will understand your needs and as said de-tune the modifications and set the chassis to stock settings, that is a whole world of hurt.
  20. Maybe this simple paper i wrote might help in what shouldn't be a gray area "geometry"..... What is it? Simply put Geometry is the X,Y,Z axis that forms a dynamic realm expressed by the suspension, steering and the cars parallelograms. Why have it? The actual tyre contact patch is about 1/3 of the total tyre width. During the suspensions transitions there is a need to maintain the position of the contact patch without distortion or saturation but still allow for comfort and indeed tyre preservation. How? Geometry has two areas that concern us after the mechanical engineers offer the final product. Static:- This is the inert position of X,Y,Z measured during a calibration. Dynamic:- This is the "expected" gains of X,Y,Z whilst in motion. The true realm of Geometry is dynamic, a fluid 3D environment applying Geometric forces that are dependable during Yaw, maintaining the contact patch..... The holey grail of chassis calibration is realizing the gains whilst the cars chassis is static... Not an easy task. The angles and forces Of the many angles we will just concentrate on three. Camber:- Is the vertical position of the wheel, it's duty is to position the cars weight to the correct area of the tyre contact patch. If the vertical position is incorrect then the vehicular weight will be disproportionate and accelerate tyre wear. Camber force:- The tilt of the camber deforms the circumference of the tyre sidewall, this forces the tyre into a conical profile that wants to roll into it's conical centre...... So if i were to describe the camber force it would be "compressive". Toe:- Is the longitudinal position of the tyre relative to the direction of travel. In a straight line a need to calculate the type of momentum albeit front-rear or four wheel drive -V- the actual rolling resistance generated between the tyre contact patch and the road makes Toe an infinitesimally difficult position to exact outside of the theoretical.... Nevertheless the ultimate aim for all drives is a dynamic 0 toe. Toe force:- Toe exerts no force unless aggressively displaced, then the car will feel unstable off the bump.... Toe cannot make a car pull. Castor Is an extension of the front wheels steer axis... By design the lower steer axis is off-set to the wheel centre and the upper rotational axis. If an imaginary line was drawn through the pivotal points it would fall in front of the tyre this is called the "trial distance", by design the tyre has no option other then to follow the trail unless interrupted by Yaw. Castor force:- Is compressive adding weight to the steering feel.... My best description is the castors energy is gyroscopic resiting any attempts to deviate from dead ahead. Time to turn Now we have a basic understanding of the angles lets see what happens when you turn....This explanation will not include inertia or transfer properties. Example taken at the front wheels on a 10 degree right lock At 10 degrees the front camber positions will change from / \ to / / the near side castor will reduce and the offside will extend. This action lowers the cars upper parallelogram on the offside corner, diagonally modifying the camber contact patch, the castor trail and the acceptance of toe on the inner wheel. Most believe the recovery of the lock is due to the castor extension or gyroscopic laws, in fact this is not true? During any lock transition the cars upper parallelogram is supported by the lower King-pins (lower swivels) as the inner castor sweeps forward the inclination of the king-pins is off-set so that the inner offside front is more vertical than the relaxed nearside front. Since the position of the king-pin is perpendicular a higher position holds more vehicular weight and since the kingpins are connected via the steering rack a natural equilibrium insists the steering will be returned. Those settings All manufacturers offer a static setting range, this allows for wear since the driven car is subject to road trauma and progressive deterioration of the suspension, so we have a range. On a fully adjustable chassis a range means nothing... Optimum positions can be achieved and you should expect nothing less if you want to experience the true splendor of the chassis. That's it..... I hope my explanation made some sense and offers a little understanding for you and what to expect at the shop from the Geometry calibration. Thank you Tony
  21. I shut down our operation at Atomic sadly....... I re-wrote the geometric settings for the IS200/ 300/ SC some years back after the owners of this forum contacted me regarding the issues members had with front tyre wear, sadly Lexus got it wrong! As for the modified IS or any car in reality that's a completely different story. Calibrating the chassis leans toward tyre saturation limits and this in turn depends on suspension, bushing compliance with a mix of duty, this being the expected role for the car? The hardest thing to calibrate in my opinion is you :o ..... Now the car is low with coilovers fitted and the desire is fast, flat high speed cornering..... Well how fast? How flat? How planted do you want the car, do you want to read/ feel the saturation or snap oversteer? Getting this information is difficult but essential otherwise one owner could say the car is un-drivable and the next driver love it.The reason for this is the human and the car chassis has a frequency, lets say a manufactured easy level that's easy for us mire mortals to drive. Modify the car then everything changes, either the human frequency ( input ) or the cars reaction, both ways there's a telling factor the geometry calibration needs to address if only to dumb the cars frequency down.
  22. Remember the numbers are not the law. Adjustment range will need a balance of figures which is totally dependent on the car. As a base those target figures will allow a fast-road come fun track day package without stuffing the tyres.
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