Tow Base?

[Ben Beacock]

In the design review from last year's competition, they mention a 5" tow base. (5-1/2" for wollongong) I've never come across this. Maybe I haven't got far enough into my Milliken book? http://fsae.com/groupee_common/emoticons/icon_smile.gif

Ben Beacock
Co-Manager
2004 Gryphon Racing - University of Guelph (http://www.soe.uoguelph.ca/uogracing)

[Ben Beacock]

In the design review from last year's competition, they mention a 5" tow base. (5-1/2" for wollongong) I've never come across this. Maybe I haven't got far enough into my Milliken book? http://fsae.com/groupee_common/emoticons/icon_smile.gif

Ben Beacock
Co-Manager
2004 Gryphon Racing - University of Guelph (http://www.soe.uoguelph.ca/uogracing)

[Charlie]

What design review is that?

Toe base is the distance from your tie rod to it's nearest suspension mount horizontally. One way to limit your rear toe deflection, which is difficult or impossible for the driver to compensate for, is to have a wide toe base.

-Charlie Ping

I just need enough to tide me over until I need more.

[Ben Beacock]

It was the review at the end of the last Detroit competition.

I wouldn't have thought that a wide tow base would be something worth mentioning, but I suppose I'll have to make sure its considered in the rear upright design. I guess the trade-off for a wide tow base would be the vertical height the a-arm/tie rod mount can be inside the wheel?

Ben Beacock
Co-Manager
2004 Gryphon Racing - University of Guelph (http://www.soe.uoguelph.ca/uogracing)

[PatClarke]

Fom a judges perspective, usually the toe-base we are talking about is at the rear of the car.
Rear steer compliance is something judges look hard at because it leads to inconsistent on track handling.
PDR

The older I get, the faster I was.

[Frank]

front toe compliance distroys ackerman

[dancin stu]

Neill Anderson, chief judge at 2003 Formula Student, picked up on it in his design review.

if you do not consider it an important factor in design, strap a large bar to your rear wheel and just see how much the wheel moves....... and then consider the cornering forces we are seeing

[Joseph]

What about the scrub radius in the rear. Eliminate scrub radius and reduce the forces on the toe base. Then you can save some of the space in the wheel for greater separation of the upper and lower ball joints. Reducing the camber loss in cornering. So what is the golden ratio between toe base and A-arm separation...... ? what do you think?

Joseph
University of Oklahoma

[Denny Trimble]

That was my theory in '99, and our car had about a 2.5" toe base. Not good! I now believe the resultant force from the tire contact patch moves around enough that you can't select one "intersection point" and assume minimal moments about it.

University of Washington Formula SAE ('98, '99, '03, '04)

[Joseph]

Good point. There are a lot of renegade forces out there. We will be using a 5 in toe base and about 9.5 in between the A-arm pivots coupled with 0 scrub and a torsion and bending stiff upright.

Joseph
University of Oklahoma