Aftermarket ISF wheel thread
07-26-18, 04:47 PM
#511
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he said 9.5 et 45 in front. Yours is 8.5 et 45. His may fit, I was thinking of rubbing issues on my 350, I forgot the fenders are different. I still think the 9.5 will be close, but it should fit.
07-26-18, 07:36 PM
#513
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msgs350 (07-26-18)
07-26-18, 07:37 PM
#514
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Doubt there will be any issues at all with +45 ET, including screwing up the suspension geometry which is what the low offset wheels do.
07-26-18, 09:11 PM
#515
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I currently run 40 offset, which is an optional wheel from Lexus. Mine are 9 inches wide, although I may upgrade to 9.5.
edit: I mean will lower offsets screw up suspension geometry?
07-26-18, 09:38 PM
#516
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Yes. They change scrub radius, instant center, and a small host of other details the suspension engineer sweated to make the car handle predictably. They might look "better" but they usually make less mechanical grip - and sometimes a whole lot less mechanical grip.
07-27-18, 10:19 AM
#519
^^^^Since the stock wheel is 8½" @ 45 and a 9½" @ 45 puts the center line in exactly the same place, so no messing with geometry. The earlier ISFs had an 8" wheel also @ 45. So there's a bit of wiggle room. I'm running RCF wheels which are 9" @ 50.
Lou
Lou
07-27-18, 12:19 PM
#520
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Lots of compromises, but when you shove the wheel an inch off centerline because it looks better (+45 to +20), you do a lot of damage to this design. It's bad enough with all the squishy rubber bushings.
07-27-18, 12:21 PM
#521
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Not to say there might be some improvement by changing these things or maybe a better compromise for your application, but without knowing what the impacts will be, it's pretty hard to say if it will be better or worse. Changing offsets is almost always worse.
Last edited by lobuxracer; 07-27-18 at 12:24 PM.
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Jwconeil (07-27-18)
07-27-18, 02:12 PM
#522
Moderator
If you keep the OEM offset, you won't hurt anything regardless of how wide the wheel is. It's the location of the center of the contact patch that shows up in all the suspension calculations. That does not change if the offsets remain the same. Arbitrarily changing ride height changes a lot - roll center, roll couple, roll axis, instant center, camber curves. All of these things impact spring and damping rates necessary to control wheel motion. If you add a different offset, then you impact all the ride height things, plus scrub radius.
Not to say there might be some improvement by changing these things or maybe a better compromise for your application, but without knowing what the impacts will be, it's pretty hard to say if it will be better or worse. Changing offsets is almost always worse.
Not to say there might be some improvement by changing these things or maybe a better compromise for your application, but without knowing what the impacts will be, it's pretty hard to say if it will be better or worse. Changing offsets is almost always worse.
my square setup rides way worse though, regardless of which car it is on. That I can’t explain.
07-27-18, 09:53 PM
#523
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Start here. Learn a lot from a guy who truly knows what he is talking about.
I tuned mini-sprint cars years ago and learned a whole lot about suspension. You'd be surprised how knowledgeable dirt track racers are about suspension set up despite the fact they only turn left.
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blackisF08 (07-27-18)
