fat tires, scrub radius, skinny coilovers?

[fireslave]

ok, so I want wide-*** tires because i want good handling, and im trying to figure out how wide i can go on an s13.

completely ignoring the fenders as an obstacle, and trying to keep scrub radius correct.

stock offset is +45mm

if i wanted to use 9.5 inch wheels instead of 6.5 inch, assuming everything else is the same (diameter & tire bulge - im not drifting here)

an offset of +7mm would keep the inner tire in the exact same position relative to the strut, but the scrub radius would be shifted 1.5 inches outward!

lowering the front end of a 240sx will make the camber become more negative because it has struts, which has the effect of decreasing scrub radius, because it causes the steering axis to point more outward.the question is, by how much? some negative camber is a good thing, but i'd think anything more than 1 or 1.5 degrees would be excessive....without massive negative camber, it wont have a huge effect on scrub radius....

which leaves me thinking about 1 thing - increasing the offset to something closer to stock - say +35mm...

this, however, decreases the clearance from the strut to the tire by 28mm compared to stock (as well as the inner fender, but whatever, can always chop holes in that if we want to.... dont know if we woudl need to).Outer fender clearance would be reduced by 48mm compared to stock, but who the hell cares about that?

this got me thinking - are there companies that make coilovers that are designed to increase the clearance, while still maintaining proper damping characteristics?

anyone have any coil-overs that are extra skinny? anyone know any other tricks for changing your scrub radius?
Modified by fireslave at 9:20 PM 1/8/2009

[fireslave]

or, more simply, does anyone know the effect certain coilover setups have on clearance as opposed to stock?

EDIT:found this...http://www.driftworks.com/reso....html(first picture i could find that showed the clearance)which makes me think that choice of coilovers dont really have much to do with anything.

So i guess im just curious as to what is clearance here. anyone have a setup that just barely clears the struts? then we could easily calculate the offset that would give us the same inner clearance for wheels of different widths

Modified by fireslave at 9:27 PM 1/8/2009
Modified by fireslave at 9:29 PM 1/8/2009

[musashin]

Most coilovers are nearly the same diameter. Usually people don't want super skinny coilovers from a durability standpoint, as they will presumably break more easily. A good general size for maximum inner fitment on s13 front wheels is 17x9 +22. Which would put a 9.5 at about +16mm. Not sure what the exact clearance on rear wheels is, but there is a member here with 10.5 +44 IIRC in the rear of his S13. If that's not exact it's close. The member is Broadfield.

[fireslave]

damn. I was hoping the offset could be a little higher than that.

atleast its a positive scrub radius though. having a slightly poisitive scrub radius is good for steering feel, although I dont know how far positive it should be for a 50% street, 50% race car...

everything i've read just says positive will cause this, negative will cause this, blah blah...

does anyone know the stock scrub radius?

[TerminalVelocity]

wait... I thought on macpherson strut suspensions lowering the car does not alter camber.

From what I've read, offset must be less than 25 to clear a 9 inch rim in the front on an s13.

[musashin]

wait... I thought on macpherson strut suspensions lowering the car does not alter camber.

Heh, you must not have a lowered car then. It definitely does.

[fireslave]

anyone know how big of a tire you can fit on a 17x9 +22 rim?

I know i've seen it done, but a lot of custom 240s have the whole drift tire thing going on...

if i could get a decent size tire on a 17x9, that would be pretty nice...

I guess I'll have to wait to do my measuring until I get a 240... anyone know of any clean s13 coupes for sale in florida?

[musashin]

Well, a 275 isn't too unreasonable, but it does balloon around the wheel edge. I would recommend a 245 or so for still a nice wide tire, but it will be pretty much square on the wheel.

[fireslave]

glad to hear a 245 fits. i've seen that on 17x9s on other cars, and I must say, it looks about ideal.

thanks

[a_ahmed]

I just posted in the other thread how i fitted my 255/40/17. I am not going any bigger for now as im with a KA24DE with boltons for track... otherwise id look into 275/40/17 front 295/40/17 rear if i had an SR with boltons 250whp+ ish...fitting the 275s takes more work though at least on an s13.. on an s14 its a joke.. lucky the s14 guys but we are a bit lighter haha. Fitting 285/30/18 on front of an s14 under stock fenders is doable that says you allz weeee