having an ifs truck i have a few comments to make here, first of all there are two types of travel.
I call the first bump travel, this is when both the left and right wheel move up or down at the same time.
The second type of travel i call flex travel, this is when one side moves up and the other moves down. both ifs and sfa have both types of travel.
sfa will also inherently have much more articulation travel than it will bump travel. ifs has the same amount of bump and articulation travel. ifs can also have much more bump travel because the center line of the wheels is not constrained by the axle. on an sfa rig the axle has to have clearance to move up, so in smaller rigs the engine size is limited, or up travel is reduced due to lack of clearance.
Another thing I'd like to bring up here is the action of the sway bar, the sway bar resists flex travel. Ifs has a higher resistance to flex travel than sfa does. This is because the sfa can exert leverage over the spring when only one side of the axle is being forced to compress, because the spring is not directly inline with the force being exerted on the tire. All of the force exerted on the tire in an ifs suspension is exerted to the spring with no extra leverage, in fact if the travel of the suspension is not parallel with the force from gravity, there will be even less force exerted on the spring, inhibiting wheel travel. this key difference is what makes sfa articulate much more than ifs. theoretically ifs could have more travel than sfa, if the limiting factor was that the axle was angled 90 from its original position, but at the same time this is a ridiculous scenario
The main reason for moving away from sfa and to ifs, is the oem's were able to make it much easier to make a safe vehicle, its a lot easier to control and tune ifs than sfa, and that means they can do it for cheaper because they spend less time doing research and development. ifs works very well at speed, because the force generated is much higher and allows the suspension to move fully. that being said, at low speed a solid axle will ride more smoothly and not loose traction as easily because the wheels travel up and down and the suspension is not fighting the leverage that ifs has to deal with. the angle of the tire is also not important, unless you aren't airing down, an aired down tire will conform to an off camber surface and also provide travel in itself. another reason to have have big wide tires.
if you are confused, I can post up a beam model and show you why ifs and sfa are different.
I feel like instead of stating facts local guru is trying to make up for his insecurities by bashing everyone that comments on this thread.
also when your tracker ifs flexes better than my meat wagon let me know.
there are no opinions, only the way each one works and which has more wheel travel in each scenario.
having an ifs truck i have a few comments to make here, first of all there are two types of travel.
I call the first bump travel, this is when both the left and right wheel move up or down at the same time.
The second type of travel i call flex travel, this is when one side moves up and the other moves down. both ifs and sfa have both types of travel.
sfa will also inherently have much more articulation travel than it will bump travel. ifs has the same amount of bump and articulation travel. ifs can also have much more bump travel because the center line of the wheels is not constrained by the axle. on an sfa rig the axle has to have clearance to move up, so in smaller rigs the engine size is limited, or up travel is reduced due to lack of clearance.
Another thing I'd like to bring up here is the action of the sway bar, the sway bar resists flex travel. Ifs has a higher resistance to flex travel than sfa does. This is because the sfa can exert leverage over the spring when only one side of the axle is being forced to compress, because the spring is not directly inline with the force being exerted on the tire. All of the force exerted on the tire in an ifs suspension is exerted to the spring with no extra leverage, in fact if the travel of the suspension is not parallel with the force from gravity, there will be even less force exerted on the spring, inhibiting wheel travel. this key difference is what makes sfa articulate much more than ifs. theoretically ifs could have more travel than sfa, if the limiting factor was that the axle was angled 90 from its original position, but at the same time this is a ridiculous scenario
The main reason for moving away from sfa and to ifs, is the oem's were able to make it much easier to make a safe vehicle, its a lot easier to control and tune ifs than sfa, and that means they can do it for cheaper because they spend less time doing research and development. ifs works very well at speed, because the force generated is much higher and allows the suspension to move fully. that being said, at low speed a solid axle will ride more smoothly and not loose traction as easily because the wheels travel up and down and the suspension is not fighting the leverage that ifs has to deal with. the angle of the tire is also not important, unless you aren't airing down, an aired down tire will conform to an off camber surface and also provide travel in itself. another reason to have have big wide tires.
if you are confused, I can post up a beam model and show you why ifs and sfa are different.
I feel like instead of stating facts local guru is trying to make up for his insecurities by bashing everyone that comments on this thread.
also when your tracker ifs flexes better than my meat wagon let me know.
there are no opinions, only the way each one works and which has more wheel travel in each scenario.