Traction Bars ...Override/underide
6th Gear Member
Joined: Apr 2007
Posts: 10,468
From: California
RE: Traction Bars ...Override/underide
Dude, I have slapper bars and trust me, when they're set up right, they do work to increase traction, not just prevent wheel hop. They're not the best out there, but they're decent for the money you spend. And CE's traction bars are different than some others, because they contact with the snubber under the spring eye rather than under the leaf like others do. Basically, when you nail it and the tires stick(slapper bars are worthless if you spin) the force causes axle wrap up as the pinion gear tries to climb up the ring gear and takes the axle housing with it. That rotation is transfered to the bars and the front end of the bar with the snubber is forced up under the spring eye(on the CE bars anyway, the spring doesn't flex since you're contacting the mounting location for the spring, which is rigid). That upward force assists with weight transfer, as the torque and forward movement are shifting weight to the rear the bars add to it slightly. Alsothe resistance of the weight of the chassis pushing against the snubber is transfered into the bar, and causes it to work like a lever and push the rear axle downward. Yeah, it's not anything tremendous but it does assist in providing an increase in traction. They're hard to beat for the money you spend, but there are much better systems out there. If you don't believe that slapper bars affect traction, then put a pair on a car, and put a crapload of preload on one side, and set it real loose on the other, when you launch, the car will pull towards the loose side because of the increased traction on the preloaded side
As far as the benefits of the Slide-a-link, YES, they are VERY real. You can adjust the bar to set proper pinion angle and can also set preload when you go to the track to increase traction even more. The Slide-a-link basically tries to achieve the same thing as other traction bars, by utilizing some of the otherwise wasted energy from the torque in the rear axle and housing to assist in weight transfer and downward axle force. The Slide-a-link is basically like a Cal Trac type setup, only with a crapload more adjustability.
As far as slapper bars, to give you an idea....last friday at the track I'd made some rear suspension adjustments, including to the traction bars before I went....the first couple runs a 2,000rpm launch slipping the clutch lightlylit the tires up like mad, and pulled of 2.5ish 60' times. I increased the preload on the traction bars, and launched again, and a 3,500rpm launch with a near dump of the clutch practically stalled the car because the tires stuck like glue. I went from 2.5 60' times with a very light launch and light clutch slipping with a crapload of wheel spin, to 2.2ish 60' times with harder higher rpm launches faster off the clutch and bogged the car both times after I adjusted it because the traction was greatly increased, and I didn't launch with enough power. Slide-a-links work WAY better, and are a LOT easier to adjust. You're not going to beat them for traction without going to a 4-link
As far as the benefits of the Slide-a-link, YES, they are VERY real. You can adjust the bar to set proper pinion angle and can also set preload when you go to the track to increase traction even more. The Slide-a-link basically tries to achieve the same thing as other traction bars, by utilizing some of the otherwise wasted energy from the torque in the rear axle and housing to assist in weight transfer and downward axle force. The Slide-a-link is basically like a Cal Trac type setup, only with a crapload more adjustability.
As far as slapper bars, to give you an idea....last friday at the track I'd made some rear suspension adjustments, including to the traction bars before I went....the first couple runs a 2,000rpm launch slipping the clutch lightlylit the tires up like mad, and pulled of 2.5ish 60' times. I increased the preload on the traction bars, and launched again, and a 3,500rpm launch with a near dump of the clutch practically stalled the car because the tires stuck like glue. I went from 2.5 60' times with a very light launch and light clutch slipping with a crapload of wheel spin, to 2.2ish 60' times with harder higher rpm launches faster off the clutch and bogged the car both times after I adjusted it because the traction was greatly increased, and I didn't launch with enough power. Slide-a-links work WAY better, and are a LOT easier to adjust. You're not going to beat them for traction without going to a 4-link
3rd Gear Member
Joined: Feb 2007
Posts: 551
RE: Traction Bars ...Override/underide
ORIGINAL: 67mustang302
Those traction bars aren't really traction bars though. They prevent axle wrap-up, but don't actually transfer any of that torque into the chassis to achieve weight transfer or push the axle down to plant the tires. If you already have no wheel hop, those type of traction bars won't do anything. Slapper bars work much better, they both prevent axle wrap up, and push upwards on the chassis to assist in vehicle weight transfer to the rear while at the same time pushing the rear axle downward and planting the tires. Cal-Tracs and Slide-a-links work even better(though thr Slide-a-links are adjustable and much better than Cal-Tracs) by not only assisting in weight transfer and downward axle movement, but by affecting the way the leaf spring moves and changing the rear axle's instant center(in a limited manner when compared to a 4-link) and moving it close under the vehicles center of gravity to increase the effective weight on the rear wheels. A 4-link suspension is the best by providing a tremendous amount of downward force and having a huge impact on instant center, moving the axle much closer to the center of mass on the car and providing a large amount of traction and weight transfer. For a leaf spring set up your best bet would be Slide-a-link traction bars, Cal-Tracs are 2nd, then slappers coming in 3rd. The under-ride style traction bars use the vehicle's chassis to absorb the energy of axle wrap-up, but doesn't use the energy of the torque to achieve any type of usable weight transfer or downward axle force. If all you want to do is prevent axle wrap-up they're fine, but they won't increase traction, only prevent wheel hop
Those traction bars aren't really traction bars though. They prevent axle wrap-up, but don't actually transfer any of that torque into the chassis to achieve weight transfer or push the axle down to plant the tires. If you already have no wheel hop, those type of traction bars won't do anything. Slapper bars work much better, they both prevent axle wrap up, and push upwards on the chassis to assist in vehicle weight transfer to the rear while at the same time pushing the rear axle downward and planting the tires. Cal-Tracs and Slide-a-links work even better(though thr Slide-a-links are adjustable and much better than Cal-Tracs) by not only assisting in weight transfer and downward axle movement, but by affecting the way the leaf spring moves and changing the rear axle's instant center(in a limited manner when compared to a 4-link) and moving it close under the vehicles center of gravity to increase the effective weight on the rear wheels. A 4-link suspension is the best by providing a tremendous amount of downward force and having a huge impact on instant center, moving the axle much closer to the center of mass on the car and providing a large amount of traction and weight transfer. For a leaf spring set up your best bet would be Slide-a-link traction bars, Cal-Tracs are 2nd, then slappers coming in 3rd. The under-ride style traction bars use the vehicle's chassis to absorb the energy of axle wrap-up, but doesn't use the energy of the torque to achieve any type of usable weight transfer or downward axle force. If all you want to do is prevent axle wrap-up they're fine, but they won't increase traction, only prevent wheel hop
Newtons 3rd law of motion(I think it was the 3rd)...for every action there is an equal and opposit reaction....which means if you bolt a solid bar from the axle to the frame and you then apply lots of torque to the axle the housing will attempt to rotate in the opposte direction with the same amount of torque and this torque WILL be placed aganist the frame at the location away from the axle and push UP thereby loading the axle with addition weight.
Sounds like a traction bar to me.
I'm positive you will tell me that I am incorrect in my statement. I don't care. I'm right and I know it.
2nd Gear Member
Joined: Aug 2007
Posts: 213
From: Unstable
RE: Traction Bars ...Override/underide
ORIGINAL: 67mustang302
Dude, I have slapper bars and trust me, when they're set up right, they do work to increase traction, not just prevent wheel hop. They're not the best out there, but they're decent for the money you spend. And CE's traction bars are different than some others, because they contact with the snubber under the spring eye rather than under the leaf like others do. Basically, when you nail it and the tires stick(slapper bars are worthless if you spin) the force causes axle wrap up as the pinion gear tries to climb up the ring gear and takes the axle housing with it. That rotation is transfered to the bars and the front end of the bar with the snubber is forced up under the spring eye(on the CE bars anyway, the spring doesn't flex since you're contacting the mounting location for the spring, which is rigid). That upward force assists with weight transfer, as the torque and forward movement are shifting weight to the rear the bars add to it slightly. Alsothe resistance of the weight of the chassis pushing against the snubber is transfered into the bar, and causes it to work like a lever and push the rear axle downward. Yeah, it's not anything tremendous but it does assist in providing an increase in traction. They're hard to beat for the money you spend, but there are much better systems out there. If you don't believe that slapper bars affect traction, then put a pair on a car, and put a crapload of preload on one side, and set it real loose on the other, when you launch, the car will pull towards the loose side because of the increased traction on the preloaded side
As far as the benefits of the Slide-a-link, YES, they are VERY real. You can adjust the bar to set proper pinion angle and can also set preload when you go to the track to increase traction even more. The Slide-a-link basically tries to achieve the same thing as other traction bars, by utilizing some of the otherwise wasted energy from the torque in the rear axle and housing to assist in weight transfer and downward axle force. The Slide-a-link is basically like a Cal Trac type setup, only with a crapload more adjustability.
As far as slapper bars, to give you an idea....last friday at the track I'd made some rear suspension adjustments, including to the traction bars before I went....the first couple runs a 2,000rpm launch slipping the clutch lightlylit the tires up like mad, and pulled of 2.5ish 60' times. I increased the preload on the traction bars, and launched again, and a 3,500rpm launch with a near dump of the clutch practically stalled the car because the tires stuck like glue. I went from 2.5 60' times with a very light launch and light clutch slipping with a crapload of wheel spin, to 2.2ish 60' times with harder higher rpm launches faster off the clutch and bogged the car both times after I adjusted it because the traction was greatly increased, and I didn't launch with enough power. Slide-a-links work WAY better, and are a LOT easier to adjust. You're not going to beat them for traction without going to a 4-link
Dude, I have slapper bars and trust me, when they're set up right, they do work to increase traction, not just prevent wheel hop. They're not the best out there, but they're decent for the money you spend. And CE's traction bars are different than some others, because they contact with the snubber under the spring eye rather than under the leaf like others do. Basically, when you nail it and the tires stick(slapper bars are worthless if you spin) the force causes axle wrap up as the pinion gear tries to climb up the ring gear and takes the axle housing with it. That rotation is transfered to the bars and the front end of the bar with the snubber is forced up under the spring eye(on the CE bars anyway, the spring doesn't flex since you're contacting the mounting location for the spring, which is rigid). That upward force assists with weight transfer, as the torque and forward movement are shifting weight to the rear the bars add to it slightly. Alsothe resistance of the weight of the chassis pushing against the snubber is transfered into the bar, and causes it to work like a lever and push the rear axle downward. Yeah, it's not anything tremendous but it does assist in providing an increase in traction. They're hard to beat for the money you spend, but there are much better systems out there. If you don't believe that slapper bars affect traction, then put a pair on a car, and put a crapload of preload on one side, and set it real loose on the other, when you launch, the car will pull towards the loose side because of the increased traction on the preloaded side
As far as the benefits of the Slide-a-link, YES, they are VERY real. You can adjust the bar to set proper pinion angle and can also set preload when you go to the track to increase traction even more. The Slide-a-link basically tries to achieve the same thing as other traction bars, by utilizing some of the otherwise wasted energy from the torque in the rear axle and housing to assist in weight transfer and downward axle force. The Slide-a-link is basically like a Cal Trac type setup, only with a crapload more adjustability.
As far as slapper bars, to give you an idea....last friday at the track I'd made some rear suspension adjustments, including to the traction bars before I went....the first couple runs a 2,000rpm launch slipping the clutch lightlylit the tires up like mad, and pulled of 2.5ish 60' times. I increased the preload on the traction bars, and launched again, and a 3,500rpm launch with a near dump of the clutch practically stalled the car because the tires stuck like glue. I went from 2.5 60' times with a very light launch and light clutch slipping with a crapload of wheel spin, to 2.2ish 60' times with harder higher rpm launches faster off the clutch and bogged the car both times after I adjusted it because the traction was greatly increased, and I didn't launch with enough power. Slide-a-links work WAY better, and are a LOT easier to adjust. You're not going to beat them for traction without going to a 4-link
suggestion that under-ride type bars such as used on the Shelby do not increase traction. Simply by emilinating hop you are increasing traction. That factor
aside, the forces applied to the under-ride bars during acceleration are applied through the bar to the chassis. These forces cause the axle to try to lift the car.
The result is effectively a weight transfer and thus causes better traction. Also as mentioned by mikthebike, under-ride type bars help with holding the axle in position and
also help with braking, so for the street the under-ride bars are in my opinion the best street car traction solution.
Jav
5th Gear Member
Joined: Mar 2007
Posts: 2,623
From:
RE: Traction Bars ...Override/underide
ORIGINAL:
6th Gear Member
Joined: Apr 2007
Posts: 10,468
From: California
RE: Traction Bars ...Override/underide
From what I understand, under rides don't do very much to push upwards on the chassis. The bar pushes forward on the bracket welded to the chassis, and a substantial amount of energy is dissipated into the chassis as the bracket tries to resist flexing forward, rather than being transfered into the chassis in a direct upward motion. This is because the bar is able to rotate on both brackets at each end because it's bushed(unless they make a style where it's solidly attached under the axle, but all the ones I've seen are bushed at both ends)Yeah, they're better than nothing and like Mike said, prevent wrap-up in both directions, which slappers don't. For the same price though, slappers will provide better weight transfer and downward axle force, so they're a better setup for someone who drag races, especially with street tires. With the CE slapper bars I have you can also adjust preload, though they're not nearly as adjustable as the Slide-a-links.
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