Antisquat and Instant Center Location

[BillyShope]

As the result of a long thread in another forum, I've added a page (Page 38 ) to my site which demonstrates that the tire patch force vector ALWAYS passes through the instant center. The spreadsheet user is able to adjust link lengths, rear pivot locations, and spread. The effect of spread on link loads is also part of the output.
http://home.earthlink.net/~whshope
over 140,000 page views

[RCJ]

In the example you show what does .175 (slope of ic)represent.Degrees ,inches?I agree that antisquat is the important factor ,but I would like to hear your opinion on how antisquat increase traction.

[BillyShope]

In the example you show what does .175 (slope of ic)represent.Degrees ,inches?I agree that antisquat is the important factor ,but I would like to hear your opinion on how antisquat increase traction.

A carpenter might refer to a roof slope as being 4 inches in a foot. (Not being a carpenter, I don't know if that's reasonable.) Anyway, if you divide 4 by 12, you get a 0.333 slope for the roof. So, the .175 slope would be equivalent to .175 inch per inch, or, for that matter, .175 mile per mile. Specifically, it is the slope of a line through the tire patch and the instant center (IC).

Antisquat does not increase traction. The antisquat value merely tells you if a car is going to squat or rise on launch. Values over 100% will rise ("hit" or "separation"), those below will squat.
http://home.earthlink.net/~whshope
over 140,000 page views

[RCJ]

Maybe I should have said values over 100% how do they increase traction?Here is my take on it.As the car rises the center of gravity rises transfering more wieght.Because of the angle of the bars raising the car most of the wieght is transfered thru the bars to the tires.Wieght transfered thru the bars hits the tires quicker than wieght transfered thru the springs.Different values of antisquat can be used to on each side of the car to load the tires evenly.

[BillyShope]

Maybe I should have said values over 100% how do they increase traction?Here is my take on it.As the car rises the center of gravity rises transfering more wieght.

Back in the fifties, we did all we could to get more weight transfer. Today, due largely to the improvements in tires, the top cars don't worry about getting enough. Their concern is directed more toward keeping the front of the car down.

Because of the angle of the bars raising the car most of the wieght is transfered thru the bars to the tires.

With 100% antisquat, ALL of the weight transfer is through the links.

Wieght transfered thru the bars hits the tires quicker than wieght transfered thru the springs.

As long as you're operating reasonably near 100% antisquat, there is very little concern for the very small amount of time it takes for a very small deflection of the suspension springs.

Different values of antisquat can be used to on each side of the car to load the tires evenly.

Very good! There's a page somewhere on my site with further information and a spreadsheet for this little trick.
http://home.earthlink.net/~whshope
over 140,000 page views

[RCJ]

For the fraction of a second when the car is lifting is there an equal and oposite force pushing down on the tires?

[CSH]

Yes thier definately is...

[BillyShope]

You betcha! That's why the idea of "hit" or "separation" is favored by most racers. But, unfortunately, as the rise comes to a halt, load is REMOVED from the rear tires. So, it's not all to the good.
http://home.earthlink.net/~whshope
over 140,000 page views

[RCJ]

With oval track cars with high antisquart values and all the wieght transfered thru the links isn't all the rear wieght seen as unsprung wieght at the tires?

[BillyShope]

I'm not certain I understand your question, but, if you're concerned that the rear suspension might act as though it was "locked up" while the car is accelerating forward, don't be. Although all of the weight transfer is transmitted through the links (with 100% antisquat), the ability of the suspension to accept other input (bumps in the track surface, cornering loads, etc.) hasn't changed one bit!

Usually, however, oval track setups don't exceed, say, 80% or so because of the tendency for high antisquat to induce wheel hop during braking.
http://home.earthlink.net/~whshope
over 140,000 page views

[velotec]

Billy,

I recomend your Mostly Suspensions pages to many who ask me questions.

You're page is over quota as it often is.

I can make a sub web on my www.racetec.cc site to host your pages if you'd like.

Tim

[BillyShope]

I can make a sub web on my www.racetec.cc site to host your pages if you'd like.

Tim

Tim, it's not copyrighted and the JavaScript is available for viewing. I would think a simple link would be sufficient. I don't know what you mean by a "sub web." Since I'm still adding pages, I wouldn't want to lose my ability to edit.

Thanks.
http://home.earthlink.net/~whshope
over 150,000 page views

[velotec]

Tim, it's not copyrighted and the JavaScript is available for viewing. I would think a simple link would be sufficient. I don't know what you mean by a "sub web." Since I'm still adding pages, I wouldn't want to lose my ability to edit.

A sub web is a web site I set up for you to host your pages. You'd have editing access just like you do now at earthlink. Not exactly sure but the link would be something like www.racetec.cc/wshope. Then you can put an automatic redirect at the eartlink page to point to the new site.

Once I set it up I'd just step away from it.

Mostly Suspensions is absolutely the most accutare source of info for racer's like me. It's a shame that it's over quota a lot of the time. Maybe this would help make it more available.

[BillyShope]

Tim, that would be great! It's exciting to see the interest in my site, with racers dropping in from every continent, but, it's discouraging to see my site unavailable for half the month when the quota is exceeded.

Please phone and we'll discuss the details. (Number is on the first page of my site.)
http://home.earthlink.net/~whshope
over 150,000 page views

[velotec]

Please phone and we'll discuss the details. (Number is on the first page of my site.)
http://home.earthlink.net/~whshope
over 150,000 page views

Of course the site is over quota and I cannot get the number.

Email or PM me. timfuffy-@-racetec.cc (remove the dashes )

Tonight I'll check into the details and make sure I can deliver on my idea.