how does scrub radius and track width affect handling: any experts??
#21
Registered User
It sounds like you are assuming that the factory setup has a zero scrub radius, this may or may not be true as I have never measured it. I would say that increasing scrub radius a small amount, in the ~1/2" range you're talking about, is not that big of a deal. Remember, more scrub radius can help add steering feel and weight, as well as slightly increase self-centering. Also keep in mind that running those tire widths with those offset will likely require a lot of camber on a lowered car with stock fenders. This extra camber will move the center of the contact patch in a little bit and reduce your "effective" scrub radius.
#22
Registered User
Bringing this one back from the dead because I've been researching track and scrub recently, and frankly, I think the info in this thread is dead wrong and it only takes a few minutes with a dynamics calculator to show why. In all my research across many boards and blogs, I see two kinds of statements: "Well, I think increasing rear track should increase push, cause I just think so" and "I have done the math, and increasing rear track decreases push."
I realize many people actually say "increasing track increases grip on the same axle." That's technically a correct statement but is very misleading. Increasing track on either axle decreases weight transfer on both axles, but primarily does so on the OPPOSITE axle. Increasing rear track width increases overall grip everywhere, but changes the balance towards OVERsteer, not understeer, because the majority of added grip is added to the front, not the rear. Pop some S2000-estimate figures into a dynamics calculator, change the front or rear track and see what happens to weight transfer.
If you want an extreme real-world example, look at the Morgan 3-wheeler. That car has a wide front track, zero rear track, and is the definition of UNDERsteer. It's also why many supercars and race cars run wider front tracks, to help put the power down at the rear on corner exit.
It's even common sense when you stop and just think about it. Widening track causes the outside tire on that end to load up more than the outside at the other end. As we all know from springs and sways, increased loading on one end means grip improves on the opposite end.
I realize many people actually say "increasing track increases grip on the same axle." That's technically a correct statement but is very misleading. Increasing track on either axle decreases weight transfer on both axles, but primarily does so on the OPPOSITE axle. Increasing rear track width increases overall grip everywhere, but changes the balance towards OVERsteer, not understeer, because the majority of added grip is added to the front, not the rear. Pop some S2000-estimate figures into a dynamics calculator, change the front or rear track and see what happens to weight transfer.
If you want an extreme real-world example, look at the Morgan 3-wheeler. That car has a wide front track, zero rear track, and is the definition of UNDERsteer. It's also why many supercars and race cars run wider front tracks, to help put the power down at the rear on corner exit.
It's even common sense when you stop and just think about it. Widening track causes the outside tire on that end to load up more than the outside at the other end. As we all know from springs and sways, increased loading on one end means grip improves on the opposite end.
On a similar note, an increase in scrub radius will also raise the 'noise floor' of the feedback received from the wheel. This may make it a tad more difficult to sense front tire grip based on FFB. The steering wheel feel is perfect for me stock. It's light for parking lot stuff, gets tight as load on the tire increases and then gets light right before peak grip.
#23
Gonna bump this thread cause it seem the most relevant.
Surprised I couldn't find the answer to this: what is the stock scrub radius? There's some talk higher up this thread that it might be close to zero (which I doubt), but did anyone actually measure it?
Surprised I couldn't find the answer to this: what is the stock scrub radius? There's some talk higher up this thread that it might be close to zero (which I doubt), but did anyone actually measure it?
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