Why is body roll bad?

[mpg9999]

Why do you want to limit body roll on a car? I'm curious to see how many people actually know this, and how many just think that they do.

RJ is not allowed to answer this, because I know he already knows the correct answer .

[Mike]

edit: i knew, but that ruined the fun so i removed my answer

[ScottyB]

motion sickness? :lol:

i don't know the real answer but i know what effects on the car i can expect and how to use that to manipulate the handling of the car.

my two guesses are (1) geometry related and (2) cg?

[Mike]

1) on the right path
2) no

[HAULN-SS]

Im not much of a road race kinda guy, but I believe it's to keep the tires planted on the track and maintain traction. Body roll around a turn takes weight off the wheels. In Drag racing however, you want a bit of body roll..well, for RWD cars that is, to plant the rear tires and give you a bit of extra traction for better 60' times and whatnot

[BLINGMW]

It isn't bad! Sure, most stock setups often have too much, but there is such thing as not enough

[mpg9999]

Im not much of a road race kinda guy, but I believe it's to keep the tires planted on the track and maintain traction. Body roll around a turn takes weight off the wheels. In Drag racing however, you want a bit of body roll..well, for RWD cars that is, to plant the rear tires and give you a bit of extra traction for better 60' times and whatnot

That is wrong. Don't feel bad though, its probably one of the most common misconceptions out there. Something about weight transfer is the answer I hear most of the time.

Blingmw, sure, there is most definatly a thing as not enough. However if we are talking about for max performance, the amount of body roll you want is very small. You want the smallest amount of body roll possibly while still being able to maintain contact over iregularities on the track surface.

Like Mike said, Scotty is on the right track with the geometry answer.

[Ryan T]

The suspension system geometry of a street car is designed to keep the bottom of the tire parallel with the road for maximum contact patch. At rest, the car's suspension has a particular geometric relationship to the road surface. Body roll changes that relationship, and reduces the suspension's ability to keep the tire parallel to the road.

Body roll effects the camber, and the camber change thus effects the traction of the tires. The more contact patch you have the more traction you have, but when a vehicle begins to lean, it forces the tires to lean onto one side. The outside tires has increased positive camber and the inside tires has increased negative camber. So a tire with a flat contact patch before body roll now has to operate on only a part of the edge of the tire during body roll. This loss of traction lets the tires give way to weight transfer to the outside of the car, which makes the car slide sideways usually.

[Mike]

you totally copied that from somewhere lol...

[Ryan T]

I didn't copy it, I restated what I read about the topic in grm.

[D_Eclipse9916]

Yeha that doesnt sound like he copied it. Thats the problem with a lot of people lowering their cars without thinking. If you have a lowered car it changes your suspension geometry. Sometimes this is taken too far and goes beyond the .rrrr.....trying to think of the technical term....Its one of the axis of suspension, but if it goes beyond that, lowering your center of gravity beyond that point is bad. Goddamnit I wish I could remember it. I remember the diagram, and im not talking about shocks and struts, im talking about the whole car suspension setup. I hope oneo f you know what im talking about. That stupid little diagram.

[mpg9999]

Yeha that doesnt sound like he copied it. Thats the problem with a lot of people lowering their cars without thinking. If you have a lowered car it changes your suspension geometry. Sometimes this is taken too far and goes beyond the .rrrr.....trying to think of the technical term....Its one of the axis of suspension, but if it goes beyond that, lowering your center of gravity beyond that point is bad. Goddamnit I wish I could remember it. I remember the diagram, and im not talking about shocks and struts, im talking about the whole car suspension setup. I hope oneo f you know what im talking about. That stupid little diagram.

Roll center and roll axis is what you're looking for.

[mpg9999]

The suspension system geometry of a street car is designed to keep the bottom of the tire parallel with the road for maximum contact patch. At rest, the car's suspension has a particular geometric relationship to the road surface. Body roll changes that relationship, and reduces the suspension's ability to keep the tire parallel to the road.

Body roll effects the camber, and the camber change thus effects the traction of the tires. The more contact patch you have the more traction you have, but when a vehicle begins to lean, it forces the tires to lean onto one side. The outside tires has increased positive camber and the inside tires has increased negative camber. So a tire with a flat contact patch before body roll now has to operate on only a part of the edge of the tire during body roll. This loss of traction lets the tires give way to weight transfer to the outside of the car, which makes the car slide sideways usually.

Werd.