Quote:
Originally Posted by 10594087
i'll take my friends car as an example, its a nissan skyline r33 gtst road car. He has changed the stock rims to Rays engineering TE37's 18x8 in the front and 18x9 in the rears. Im not sure which information you would require.
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I have done a lot of development work on GTS-t's as I like them for their low initial purchase cost, their tail happy, fun handling, and their much lighter weight than the portly GTR. His problem may well be that in order to accommodate wider rims and tyres within the stock wheel arches he has changed wheel offset a lot. This alters the kinematics of the suspension and can result in tram lining and wooden steering feed back. The stock rubber suspension bushes are now probably too compliant to cope with increased loadings and are failing to constrain the geo under some loads. Quite often people lower road cars with no real understanding of what it will do to bump steer, camber curves and roll centre heights. A lower car is often a slower car. The R33 in particular has terrible rear bump steer changes when lowered much at all, and the front roll centres move to where the car tries to roll more when lowered. Stock or near stock ride height is best, short of buying or fabricating a lot of custom stuff to accommodate lowering whilst maintaining good roll centre control and minimising bump steer. Finally, the budget is often strained with buying nice light rims, and corners are cut on the tyre mounted upon them, which is plain daft. Bear in mind both race and road car designers often start with a wheel and tyre size as their first defined object, and a vast amount of stuff is based on their characteristics, fiddle with them only of you are sure you know what you are doing. I see disastrous wheel and tyre combinations on all manner of road cars as my everyday job, much more rarely do I see well thought out modifications that actually make a car quicker or nicer to drive. Modern cars that run ultra wide and low profile tyres as standard wear have, or should have suitable geo to keep a stiff sidewalled wide tyre flat on the road, add such tyres to a car not designed for them and their discomfort shows in odd tyre wear and none linear handling as the tyre tread partly lifts off the road in cornering or braking due to unsuitable camber control. I am convinced there are many modern cars with ultra low profile rubber that would be far nicer to drive on a taller sidewall, but the buying public mainly associate rubber band tyres on huge diameter rims with having good looks and performance. It's a bit like platform shoes, the media made us all of a certain age believe they were a must have, whilst we broke ankles and stumbled around trying to look "cool"
