Tony

Yes the extra width and the harder sidewall.. The 225 will ride the troughs in the road much more than the 185.... in addition a 45% aspect ratio has a much harder sidewall so it's less resistant to absorbing the trough and tends to steer if the compression is only on one sidewall. On top of all that the continuous centre band is designed to retain directional control so this also steers. As for the nails in the front.... that's just very bad luck... 99% of punctures are at the rear.

Yep Crap Fit decided that the best way to preserve tyre wear would be to put the tread on the 'in side' of the tyre.... i think they have cornered the market since most cars they align experience this phenomenon

Look closely at the tyre were the drive shaft enters the hub..... that narrow band of white near the top is the inner construction of the tyre exposed due to the wear.... only 10mm wide but very deep in comparison to the rest of the tyre......... hence the 'silent killer'......... and horror of the week!

Still everything looks good.... but lazey.. there is a hidden rule for your type of car regarding the castor and kpi... this rule is the 16 degree club? Their needs to be a constructed configuration between the castor/kpi angles generating an overall figure of about 16 degrees for a RWD car of this type, in your situation it's 13 deg kpi + near to 4 deg castor at almost 0 toe. Due to the lack of weight acting on the kpi the inclination is 'declined' hence the 13.38 position. This means any small reaction to the steering would 'incline' the kpi and make the angle active, but this reaction is shallow in the most desperate of cases.... so we are left with castor and toe.... The Mechanical castor trail is very low at 4 degrees with a very 'typical' small turning radius. Adding inertia with a bigger wheel would add a pneumatic trail and centrifugal resistance, but still to low to be of any value. Now we have just toe. At 0.4mm+ partial equals .8'+ total front toe this is to low.... 20' positive total is a conservative position... 40' is even possible without violating the tyres..... So in summery we could have FRONT camber: conical/ compression at 48'- and the reaction would be at about 30' intruding the kpi with equal values of 30'. castor, mechanical at near to 4 degrees, reactive to the rear bump/compression at about 20'.... this is very low due to the suspension modifications..... bump on/off would be low in support. castor, pneumatic and scrub radii -10 to 20 mm taken at the 0 off-set. Front toe seems to be the only evolution here.... 20' positive 'partial' 40' total seems wise to me.

oh dear........... get out of this one Tony?.... The Vicars wife on the symmetrical tyre would not normally need to experience the required demand predicted at the absolute top performance from this configuration................ phew that should do it? In truth the product mirrored your previous fitment.... reality would suggest that Bazzas 888s would have been better.

Continuing to remind you why we are here, this is this weeks example. This example was again from a Lexus IS200 but with a difference. 1: Unusually the wear was on the inside at the rear. 2: If you look close you can see how confined the wear is.... and it was due to the camber position 'the' (silent killer) 3: And this one got me?.... the owner had just replaced the front tyres because of the wear on the inner edges, then decided to come to me and have the geom set... but the shop failed to notice and warn the owner about the condition of the rear tyres, needless to say he was horrified, and the shop lost another sale? Till next week then.... Anyone else got some horror pictures to show in the mean time?

Looks good so far?..... can you display The KPI aka SJI The wheel size and off-set (front) please.

Their are three main patterns on the market All offer good tails to why you should buy any one of them.... so in true wim fashion here is the real story..... Symmetrical pattern Manerfacturers comments Superb harmony of comfort and stability Smooth drive reduces stress on long journeys Premium wet handling for more safety wim comments By today's standards this pattern is only suitable for the 'town car'.... the Vicars wife type of driving. The pattern is reliant on silica content in the rubber and compression for grip. It has high harmonics and due to the close action of the tread this type of tyre is prone to punctures.... Historically (UK) in the NSR. Asymmetrical pattern Manerfacturers comments A state of the art driving precision from Formula One technology Response and control beyond your dreams Superb wet grip provides ultimate safety wim comments Commonly found on German sports marques and certainly better than the symmetrical pattern but there are some evident flaws with this type of tyre. 1: The majority of the pattern is continuous radial banding, the principle is to allow the tread to steer the car longitudinally thus adding security at speed.... one very evident complaint is that the tyre 'tram-lines' very badly since it does not want to deviate from straight ahead and is conscious of the road condition. 2: The outer band (the widest) offers the highest resistance during 'turn in' so the sipes (cuts in the band) are very shallow, this belays movement in the band for the control.... this is all well and good but the down side is that the 'sipes' DO NOT go down to the legal limit. Consequently when the tyre is 75% worn the outer band would appear bald. 3: The tyre has wide gaps between the tread to capture water, initially this raises the aquaplane speed, evident loss of performance increases as the tyre wears. Unidirectional (US) Directional UK Manerfacturers comments High-level wet braking and cornering, with less risk of aquaplaning Great handling and steering response Aggressive tread pattern, stylish sidewall and with rim-guard redundent protection. wim comments Fundermentally all true. The pattern acts by compression and centrifugal dispersal, so it has a rapid footprint. Not sensitive to tram-lining because the pattern is lateral. and the tread has no 'sipes'. My only real criticism is that the pattern is 'pinch sensitive'. This is a condition that generates a pattern of wear called 'Heel and Toe'... a scallop wave effect mostly apparent on the rear tyres of a front wheel drive car. So what are your thoughts regarding the pattern you drive on...

Oh my word.... sorry about the nails...and the seat!.. does this experience make you happy or angry toward the TC... since it was the lack of it that caught you out?

Good question The positions of the toe initially determines the rate of turnin ver drive type. A 0+0 on a RWD with the other angles set at stock would 360 the car at every opportunity.... the under-over steer would not make the drive pleasant, totally unpredictable. The F 0+0 R1+1 will reduce over-steer by controlling the rear slip angle... basically controlling the 'brake point' Camber is a compressive force, so at the rear this promotes under-steer.... this is wise for the RWD Camber at the front is another story.... off-sets measured from the wheel and King Pin determine the Scrub radius... if the radius is wrong then the forces directed to the tyre would make the car handle very bad indeed. Contrary to what i have read elsewhere the radius is adjustable depending were the camber is adjusted... if the camber is adjusted via the strut or turret then little movement will be seen at the KPI... but if the camber adjustment is made via the lower wishbone then there is an immediate movement toward the KPI then the camber angle.... so in this case you can target the scrub radius. Castor..... we have mechanical/ pneumatic and the steering axis involved here...... in reality the castor is disinterested in the toe position..... the kpi/castor/toot and turning radii have to be a stand alone explanation... i would need to add areas like modifications/wheel size/ down/ breaking forces into the explanation... and this would mask your initial post. Fun stuff this Geometry lark but it can become complicated if to broad.... refined questions open much debate which is healthy for you and the club

The under/over steer phenomenon has been exampled here in wim but there are some direct or indirect consequences for the Modified car you may find interesting either to exploit or belay. Component___________________Reduce Under-steer_____________Reduce Over-steer Weight Distribution....................Centre of gravity toward rear....................Centre of gravity toward front Front coils..................................................Softer................... ................................. Stiffer Rear coils.................................................Stiffer................... ....................................Softer Front sway bar..........................................Softer............................. ..........................Stiffer Rear sway bar...........................................Stiffer........................... ............................Softer Front tyre selection (1)....................Larger contact area (2)..............................Smaller contact area Rear tyre selection.........................Smaller contact area..................................Larger contact area (2) Front wheel rim width/diameter...............Larger (2)...................................................Smaller Rear wheel rim width/diameter................Smaller................................................. ....Larger (2)Front tyre pressure............................................Higher pressure...........................................Lower pressure Rear tyre pressure..............................Lower pressure...........................................Higher pressure Front camber................................Increase negative camber............................Reduce negative camber Rear camber..................................Reduce negative camber............................Increase negative camber Rear spoiler.............................................Smaller..................... ..................................Larger Ride height front.......................................Lower............................... ...........................Raise Ride height rear........................................raise............................... ............................lower Front toe................................................Increase..................... .................................Decrease Rear toe................................................Decrease..................... .................................Increase (1) Tyre contact is increased by using wider tyres, or tyres with less grooves in the tread, but fewer grooves has the opposite effect in wet weather. (2) These improve road holding, under most conditions.

Very nice of you to say so Tony I am truly flattered. When we started it was a case of "The blind leading the blind" now I think it is more "In the valley of the blind the one eyed man is King" indeed... twas a day to remember when the 'Tezza' went arse up looking at each other with our faces set on stun Um.............Yeh, that I feel will be one of the great unsolved mysteries of the 21st Century. As bit of background for others, we jacked the car up, shortened the dampers 30mm, put the wheels back on and the back of the car was 30mm higher than when we started And we laughed and laughed 'not' ........... valuable learning curve in truth... i think the best way to do something right is to understand why it has gone wrong.

Very nice of you to say so Tony I am truly flattered. When we started it was a case of "The blind leading the blind" now I think it is more "In the valley of the blind the one eyed man is King" indeed... twas a day to remember when the 'Tezza' went arse up looking at each other with our faces set on stun

MacRS200 with the knowledge you have regarding coilovers and the set-up you should be called the 'Coil King' .......... when i have my new centre i am looking forward to that 'weeks training'

There is a huge need for tyres on Track/Drift days. Sound second hand expendable rubber for these events would lend support and revenue if taken seriously.... food for thought

Solid idea Dan... would Discounts consider supplying (Disposable) tyres for this purpose?.. understand i am not endorsing second hand tyres, just tyres that would commit to this cause.

Your car will lend valuable information toward others that might follow the same path (when released)...... in view of how things evolved time and time again was you surprised how the coils affected the Geom. Bit of a mission these coilovers arent they! In all honesty I dont even know what preload is, how does it work? BTW, I understand what you mean with letting them settle etc, but I dont fancy going back at cost 10 times. So...I was thinking..get them set up...settle...go back again and thats it? Do I really need to go back so many times? Obviously for perfection yes, but Im not racing driver, go on track like 3 times a year max (or planning to)...would it be worth it? You just need to consider the fact that when the coils a fitted the Geo will be wrong.... after a 1000ish miles the coils would be near to settled, but in between the tyres could wear. At the end of the day it would be worth it!

Best of luck with the move.... 'stress' at the max!.... you realise the SR will need to be re-calculated after the spacers are fitted ....... Mike you are an ideal candidate for the ARIGO Geometry machine... it will save me hours

Dan we have about 5 cars a month complain the car is pulling to one side after new tyres are fitted, and that's just one centre....... even i cannot Police the conduct and attitude of the fitters if they don't want to listen and respect the information. In Research i have contacted other independent tyre companies and non of them knew what the markings meant. So it can be assumed that this problem is country wide........... oh by the way the bigger UK companies would not comment

The handling is excellent! If anything needed to change I would say another 0.3-0.5 degree -ve camber on the rear and perhaps a slightly higher oversteer tendancy. To add oversteer i would need to reduce conical camber or reduce lateral toe from your positions at the rear... or if it were possible on the SW20 i could increase the castor by a degree and provoke diagonal lifting.. as seen in TC on the bends.... i would love to add 30' on your cars castor just to see how much difference you could feel with such a solid modified construction.

Jap Devil maybe you could advise me here.... next week i have two SW20 to set for track days. Neither owners have specific settings but both want the car to feel secure.. from the positions you now have is there any area that makes you or the car feel nervous. Your personal feed back would help me advise them since you drive a modified car and we have your Geo image already.

How are things going with this project?

To Triangulate were the problem is i would need other information from the Geometry report... like KPI or SJI and the Castor positions

Has the car been lowered.......... if yes then the positions are fine since the coil rate would be higher, if not then the camber curve will wear the tyres on the front very fast on the insides. The shop has done a good job making the Geometry symmetrical though!

Your car will lend valuable information toward others that might follow the same path (when released)...... in view of how things evolved time and time again was you surprised how the coils affected the Geom.